Suppose you're designing a rifleman's front sight.
The Rifleman's front sight is ___ MOA wide because ___.
The Rifleman's front sight is ___ MOA tall because ___.
The Rifleman's front sight is shaped like ___ because ___.
I have some ideas of my own, I'll share later.
Any thoughts on these dimensions/forms, why?
Front sight design has evolved over the years. Early examples were mere nubbins out of the end of the barrel to give a simple visual index and served that role as does a shotgun bead. Moving into the modern era, front sights were often half-moon shaped. Indeed, many surviving buffalo guns, Rolling Blocks, Sharps and Ballards, can be seen with replacement front sights fashioned from a section cut from a coin. Here width and obtainability seem to have been the overriding concerns.
In our time, sights have continued to evolve, from an undercut front blade (as seen on the British No4Mk1, US. 1903, et al, to a flat blade, as seen on the M1/M14 series, to the round post found on the M16A1, to the square post found on the current M16 series. Current theory espouses a flat-topped blade or post. In the past, pointed blades, beads or dots were often used.
Visually, the undercut blade provides the sharpest picture, provided that it is sharp and undeformed. The "flat" (the M1 blade is slightly undercut) blade is next, provided that its axis is parallel to the axis of the rifle. The rounded post has been, by and large, discarded, in part because of deflection problems and an indistinct profile in some lighting conditions.
Front sight height is largely determined by rear sight type. Obviously, if the rear sight is semi-fixed (windage only), elevation adjustments must be made at the front end, either with an adjustable front sight (M16) or with available different height front sights (Enfield). Either of these presume a "zero and forget" approach, since no one is going to adjust their front sight when rounds are incoming. All things being equal, the front sight height should place the top of the front sight in the middle of the notch or aperature when a proper cheek weld is taken, and the rear sight is in its "normal" position. That seems obvious, but the number of rifles which are lacking in this regard is legion.
Width is, largely, a matter of personal preference. Good work can be done with a thin blade, provided the operator has the available light and the visual acuity to use it. A thick blade is easier to see in all lighting conditions, but sacrifices some precision. The standard M14 sight is useful for estimating range (see Fred's Guide), but if it's mounted on a SOCOM or Squad Scout variant, the equation changes. Any front sight can be used as an estimator of range, provided the operator knows how much his sight subtends, that is, how many minutes of angle does it cover.
To be continued ?....
Width of the front site should be the width of your target at the specific max range which is still within Battlesight Zero distance.
For most rifles, that translates to 7 MOA as the correct width of the front sight, so that you can use it as a range-finder at unknown distances. Any man-size target as wide or wider than the front blade would be within BSZ distance and no need to fuss with sight elevation changes/holdovers. Simply take the shot. Clean, simple, easy.
If you have a preference for a thinner front sight blade, 4 MOA would work as well. ;D
A Rifleman "wastes not, wants not."
Having an integral range-finder which works right at the moment of acquiring sight pic is a wonderful asset to have.
The sights on a rifle are defined by the job it has to do. Fred defined the sights on an iron sighted military rifle.
The muzzle loading rifles used by the founders of this country had very different sights. The front sight was a thin sliver of gold, silver or sometimes brass. The rear sight was a notch just big enough to accomodate the front sight, really no more than a nick in the sight base. This sight was used when hunting in the deep woods that covered the east. The canopy of trees was so thick that to walk in the forest was to walk in a darkness close to night. The rifleman would take aim by placing the little speck of light, gathered by the bright metal sliver in the notch and placing that on the aiming area. These sights did not work well in bright sun light as they were hard to see and they did not work well if you had to shoot many shots because the heat waves from the barrel obscured the sights sitting low on the barrel.
When the country moved west to the plains the sights changed to accomodate the new job they had to do. The front sight became an iron post when viewed from the back. The rear sight sported a larger notch to align the front post in. The rear sight usually was a buckhorn sight with arms that came up and around over the sight. This provided what today is called a ghost ring for quick shots up close. Longer shots took advantage of the post and notch for precise alignment.
VAshooter
The highest evolution of the front sight, at least in terms of precision, is the front aperture sight. Universally used in the target-shooting world, they are rarely seen outside of that rarified atmosphere. Why? Because they have little application in the field. They are somewhat slower to align, they require near-perfect lighting conditions, they tend to obscure too much of the target area, they tend to be fragile, and they make holdover or holdunder difficult. In addition, targets closer or further than the optimum distance make their use problematic- too close, there is nothing to index on, too far, and the target is difficult to bring into focus. Bear in mind that in the target world, the front aperature is often an adjustable iris used in conjunction with an adjustable-iris equipped rear sight. With such a setup, target focus is not an issue.
The often seen hooded or ringed front sight suffers from some of these same problems when used in conjunction with a rear aperature. When used at speed, the eye attempts to align both front and rear aperatures with perfect optical precision. As a result, "over-fussing" the shot often occurs.
So, the proper attributes of a modern front sight seem to be visual sharpness, useful width, lack of distracting reflections, and ease and rapidity of alignment. In addition, protection of the front sight from physical damage has proven to be necessary. It is disconcerting to shoulder the rifle, only to find that your sight is gone or bent. Thus the development of wings, as seen on almost all modern military rifles. The wings themselves may serve as a rudimentary sighting system, used to bracket the target in very dim lighting conditions, or when time frames are extremely short.
Rugged SKS carbines. How to improve this arm for target shooting? Its design fulfils its mission to function reliably in the hands of a mid twentieth-century soldier. But the modern target, silhouette and pop-up shooter can improve the original sighting system.
This project was borne of observing a couple of new HP shooters who were getting frustrated that they couldn't hit their target reliably from 300 meters, let alone 600 meters. The problem was not their rifles of choice, SKSs. They simply couldn't adjust their sights.
I don't expect the SKS to best an AR or M1A in terms of accuracy, but these SKS shooters should have been able to adjust their sights onto target, and producing 3 to 6 MOA groups: acceptable military accuracy from their carbines.
Unfortunately, the soldier-proof design of the SKS kept the sights locked off target.
I developed a few things to help these guys out, and anybody else for that matter who'd like to add some precision to their standard, 20-inch barrel SKS.
Windage adjustment. Of course drift clamps are available for $5 to $10 from numerous sources. But how much adjustment do you get per revolution? Riflemen must know. If you already have a clamp, you can figure out the lateral adjustment by the pitch of the windage screw.
For US pattern bolt,
MOA per revolution = {[1 / number of threads per inch] / Sight Radius in inches} * [180/3.14159]*60
US Example: I have a US pattern drift bolt, 24 threads per inch.
1/24/18.875*180/3.14159*60 = 7.6 MOA per revolution.
Metric Example: I have a metric M12x 1.5 drift bolt. That's 1.5mm per thread.
Sight radius is 18.875 inches, or 479.4mm.
Use this for metric threads:
MOA per revolution = mm per thread / Sight Radius in mm * 180/3.14159 * 60
1.5/479.4*180/3.14159*60 = 10.8 MOA per revolution.
Now, if you have a C-clamp drift tool, you can calc the MOA per revolution and stamp that on the tool.
The SKS front sight is a metric M6 x 0.75 pattern; that's 0.75mm per thread. That works out to 5.4 MOA vertical adjustment per revolution.
By sight radius, I mean the distance from your front sight to the rear notch; 18 7/8 inches , or 479 mm , on a standard 20" barrel SKS.
I made my own drift clamp, & calculated the MOA per drift screw revolution, and stamped that on the tool. In my case, it's 7.6 MOA per revolution with a 24 thread per inch bolt.
The SKS needs an elevation adjustment tool that stays with the rifle; this can be easily done and adds negligible weight to rifle. I had made my own elevation adjustment tool years ago; it consists of a segment of steel tubing, ¼ inch 5/16 inch diameter, ¾ inch long, which has been squeezed oblong on one end to slip over and snug against, the front sight flats, and has been drilled through the side, on the opposite end, to accept the standard SKS cleaning kit drift punch as a torque handle. The elevation adjustment tool fits inside the buttstock cleaning kit along with everything else.
With these tools, you'll be able to adjust, and know how far those adjustments move you.
Now for the front sight. I never liked the short, fat Chinese original sight on my SKS. Its large size made for a poor sight picture, hindering careful shooting.
Redesigning the SKS front sight, I made a list of what the front sight needed to do:
*Improved size fit with notch rear sight, i.e. narrower and taller than standard front sight.
*Improved silhouette definition of sight: rectangular geometry/flats on post like M16A2 front sight instead of cylindrical post.
*Range finding capability: Along lateral dimension, as well as along the vertical dimension. The front sight should range a target 24 inches wide, 70 inches tall, with the 300 m battlesight zero as a starting point.
The resulting front sight post presents a flat, rectangular profile to the shooter's eye, and is adjustable in 1/4 revolution increments vertically like an M16 A2 front sight.
The width of the sight measures 0.062 inches, because a 24 inch wide target is as wide as the front sight at 300m range. The front sight measures 0.181 inches tall because a target 70 inches tall appears exactly as tall as the front sight at 300 meters.
That works out to a 7 MOA wide, 20.4 MOA tall front sight.
Now here is a rapid, accurate way to calculate range; I'll call it the reciprocal fraction ranging method. Don't head for the hills; it's easier than it sounds. It works like this.
A fraction is one number divided by another number; for example a / b.
The reciprocal is simply swapping the two numbers. Reciprocal of a/b is b/a.
Reciprocal of 2/3 is 3/2. Easy.
How does this range targets?
Sight picture includes the sights and the target, right?
If the target appears exactly as tall, 1/1, as the front sight, then the target is 1/1*300 m away, which is 300 m away. (1/1 is its own reciprocal.)
If the target is 2/3 as tall as the front sight, the target is 3/2 * 300 m away, or 450 meters.
... ¾ as tall as the front sight, the target is 4/3 * 300 m = 400 m away.
4/5 as tall as the front sight, the target is 5/4 * 300 m = 375 m away.
... ¼ as tall as front sight, the target is 4/1 * 300 m = 1200 m away.
Compare the target to the front sight, assign a fraction to the target relative to the front sight, and multiply 300 m by the reciprocal of that fraction.
The exact same relationship exists with the width of the front sight.
If the target is ½ as wide as the front sight, the target is 2/1 * 300 m = 600 m away.
If you can assign the target a simple, fractional size in comparison to the front sight, you can range the target rapidly, accurately. That's why you have a ladder on that SKS- If you can range targets, you can deliver accurate fire, right away, to at least twice the distance of the battlesight zero using a range-finding SKS sight.
Changing the rear sight of the SKS to an arpeture rear sight (on the receiver cover) is another good alteration. Tech Sights makes one, and you can simply take an after-market cover (scope mount type) and weld or otherwise attach a "peep sight" to it.
You will obviously have to recalculate the adjustment cvalues, as the sight radius will change.
[attachment=1]
Quote from: Francis Marion on September 17, 2008, 04:08:28 AM
Rugged SKS carbines. How to improve this arm for target shooting? Its design fulfills its mission to function reliably in the hands of a mid twentieth-century soldier. But the modern target, silhouette and pop-up shooter can improve the original sighting system.
This project was borne of observing a couple of new HP shooters who were getting frustrated that they couldn't hit their target reliably from 300 meters, let alone 600 meters. The problem was not their rifles of choice, SKSs. They simply couldn't adjust their sights.
I don't expect the SKS to best an AR or M1A in terms of accuracy, but these SKS shooters should have been able to adjust their sights onto target, and producing 3 to 6 MOA groups: acceptable military accuracy from their carbines.
Unfortunately, the soldier-proof design of the SKS kept the sights locked off target.
I developed a few things to help these guys out, and anybody else for that matter who'd like to add some precision to their standard, 20-inch barrel SKS.
Windage adjustment. Of course drift clamps are available for $5 to $10 from numerous sources. But how much adjustment do you get per revolution? Riflemen must know. If you already have a clamp, you can figure out the lateral adjustment by the pitch of the windage screw.
For US pattern bolt,
MOA per revolution = {[1 / number of threads per inch] / Sight Radius in inches} * [180/3.14159]*60
US Example: I have a US pattern drift bolt, 24 threads per inch.
1/24/18.875*180/3.14159*60 = 7.6 MOA per revolution.
Metric Example: I have a metric M12x 1.5 drift bolt. That's 1.5mm per thread.
Sight radius is 18.875 inches, or 479.4mm.
Use this for metric threads:
MOA per revolution = mm per thread / Sight Radius in mm * 180/3.14159 * 60
1.5/479.4*180/3.14159*60 = 10.8 MOA per revolution.
Now, if you have a C-clamp drift tool, you can calc the MOA per revolution and stamp that on the tool.
The SKS front sight is a metric M6 x 0.75 pattern; that's 0.75mm per thread. That works out to 5.4 MOA vertical adjustment per revolution.
By sight radius, I mean the distance from your front sight to the rear notch; 18 7/8 inches , or 479 mm , on a standard 20" barrel SKS.
I made my own drift clamp, & calculated the MOA per drift screw revolution, and stamped that on the tool. In my case, it's 7.6 MOA per revolution with a 24 thread per inch bolt.
The SKS needs an elevation adjustment tool that stays with the rifle; this can be easily done and adds negligible weight to rifle. I had made my own elevation adjustment tool years ago; it consists of a segment of steel tubing, ¼ inch diameter, ¾ inch long, which has been squeezed oblong on one end to slip over and snug against, the front sight flats, and has been drilled through the side, on the opposite end, to accept the standard SKS cleaning kit drift punch as a torque handle. The elevation adjustment tool fits inside the buttstock cleaning kit along with everything else.
With these tools, you'll be able to adjust, and know how far those adjustments move you.
Now for the front sight. I never liked the short, fat Chinese original sight on my SKS. Its large size made for a poor sight picture, hindering careful shooting.
Redesigning the SKS front sight, I made a list of what the front sight needed to do:
*Improved size fit with notch rear sight, i.e. narrower and taller than standard front sight.
*Improved silhouette definition of sight: rectangular geometry/flats on post like M16A2 front sight instead of cylindrical post.
*Range finding capability: Along lateral dimension, as well as along the vertical dimension. The front sight should range a target 24 inches wide, 70 inches tall, with the 300 m battlesight zero as a starting point.
The resulting front sight post presents a flat, rectangular profile to the shooter's eye, and is adjustable in 1/4 revolution increments vertically like an M16 A2 front sight.
The width of the sight measures 0.062 inches, because a 24 inch wide target is as wide as the front sight at 300m range. The front sight measures 0.181 inches tall because a target 70 inches tall appears exactly as tall as the front sight at 300 meters.
That works out to a 7 MOA wide, 20.4 MOA tall front sight.
Now here is a rapid, accurate way to calculate range; I'll call it the reciprocal fraction ranging method. Don't head for the hills; it's easier than it sounds. It works like this.
A fraction is one number divided by another number; for example a / b.
The reciprocal is simply swapping the two numbers. Reciprocal of a/b is b/a.
Reciprocal of 2/3 is 3/2. Easy.
How does this range targets?
Sight picture includes the sights and the target, right?
If the target appears exactly as tall, 1/1, as the front sight, then the target is 1/1*300 m away, which is 300 m away. (1/1 is its own reciprocal.)
If the target is 2/3 as tall as the front sight, the target is 3/2 * 300 m away, or 450 meters.
... ¾ as tall as the front sight, the target is 4/3 * 300 m = 400 m away.
4/5 as tall as the front sight, the target is 5/4 * 300 m = 375 m away.
... ¼ as tall as front sight, the target is 4/1 * 300 m = 1200 m away.
Compare the target to the front sight, assign a fraction to the target relative to the front sight, and multiply 300 m by the reciprocal of that fraction.
The exact same relationship exists with the width of the front sight.
If the target is ½ as wide as the front sight, the target is 2/1 * 300 m = 600 m away.
If you can assign the target a simple, fractional size in comparison to the front sight, you can range the target rapidly, accurately. That's why you have a ladder on that SKS- If you can range targets, you can deliver accurate fire, right away, to at least twice the distance of the battlesight zero using a range-finding SKS sight.
Great post, FM. "Homework" that you've done on behalf of every SKS-shooter! (They should thank you, for sure!)
Now, you SKS shooters take the data to the range, and see how close it comes to your rifle's data. I bet it puts you in the ballpark, at least - and likely, is bang on the money.
PS: The "reciprocal fraction ranging method" is great for simplifying the range estimation prob, but needs a more user-friendly name... ;D Only RWVA instructors could get away with using that name - and only, then, if they want everyone to instantly "tune off". >:( ;D ;D ;D
Reciprocal fraction is too cumbersome, call it instead the Inverse Ranging Method.
First, compare the target to the front sight with a simple fraction.
"The target is 2/3 as tall as the front post"
"The inverse of 2/3 is 3/2"
Multiply BSZ range times the inverse.
"300m BSZ range times 3/2 is 450m."
Voila!
FM, you make it sound so simple that
even I should have thought of it.
Keep up the good work!
AK and SKS owners: Are front posts interchangeable with these rifles, or are thread patterns/overall height of post incompatible?
In other words, could you place an SKS post into an AK drum?
how about the front sight of a Fal?
what about it...exactly?
AK and SKS should interchange. Not sure if they're indentical, so MOA and post width may vary.
FAL is a whole different matter. There was numerous variations made, with 3 basic categories, Metric, Inch and Israeli.
You may find all Inch sights interchange, as they were used by Briain, Canada and Australia. Rhodesian will be questionable.
I'd PM GMB74 and funfaler and ask them, they're better FAL men than I am, for sure. I know the L1A1 (inch) and not the metric stuff.
AK and SKS thread patterns are the same. Overall post height, including thread, is different; AK post having longer threaded shaft.
but, an SKS sight will fit into an AK drum, but I suspect an AK sight might bottom out in an SKS drum assembly. Probably, an AK front post has a smaller diameter than an SKS post, since it's closer to the eye.
If you can measure the width of your front sight blade, and its height, to the nearest 0.001 inch, and measure the distance from shooting eye to the front post with a tape measure, you can estimate how many MOA wide and tall the post is.
A rough calc this way-
Front post MOA width is
MOA = (Post width in inches ) * 10800 / (Distance from shooting eye to front post in inches) / 3.14
Front post MOA height is
MOA = (Post height in inches ) * 10800 / (Distance from shooting eye to front post in inches) / 3.14
Thank you for all this info.
As far as the AK/SKS sights go, everything I've read points to the sights being completely interchangeable.
But definately not identicle.
I suspect the drums may be interchangeable, even.(I'll check when I get home.)
My AK has longer thread, but I believe it's just made up for by a shorter post.
So overall travel may be the same. Oddly enough, my Romanian AK has a wider post than my Chinese SKS.
They, just opened up the notch on the rear.
This more than likely varries with manufacturer.
Again thank you.
Very good information,but I'm terrible with math. It makes no sense to me at all. I only know that the new sight post I got from Francis will cover a man silhouette target at 300 meters. :)..I also have no clue on how to use the windage clamp I got from him.. ++)
Well Bill, you get to an AS and you'll learn to see things in terms of minutes of angle... and then all the info stamped on the tool will make sense.
Windage clamp is used for adjusting... windage. It moves point of impact left or right.
Riflemen must know how many MOA they need to shift their sights. The windage drift screw pushes the front sight 7.6 MOA each time you make one complete turn of the screw.
Fortunately, Riflemen don't have to carry around slide rules to figure this out, they instead apply the rule of thumb that, at 100 yds, one MOA is an inch wide.
So if 1 MOA is one inch wide at 100 yds, 7.6 MOA is 7.6 inches wide at 100 yds.
As Barbie once said, "Math is hard!" So, don't think of it in terms of math, think of one MOA as a long, thin triangle. The pointy end starts with you, the two very long legs extend toward the target, and the third leg, on the target paper, is an inch long.
Since this is a one MOA triangle, it doesn't matter how long the triangle is: it can be 1000 yds long, or 25 meters long, it's always a 1 MOA triangle, at any range.
Now let's get you to the shooting range, a nice one with 1000 yard capability.
You set down to engage a 1000 yard target. Somebody has laid down a 1 MOA triangle for you, very helpfully, extending all the way from you to the target. At your feet, you see the sharp end of the triangle. As you look downrange at the target, and decide that since this is such a fine triangle you'll clear and safe the line, and then walk downrange to check out the other end of this 1 MOA triangle. You walk the 1000 yards down to the target, and want to measure how wide across is this magnificent triangle at the target. BUt you forgot your tape measure, and have to walk back to your range box for it. As you walk back again to measure width of the 1 MOA triangle, you stop at the 100 yard berm and just take a quick measurement. The triangle is an inch across at 100 yds. On you way to the 1000 yard berm, you stop at the 200 yard berm and measure the 1 MOA triangle- it's 2 inches across. An amazing coincidence? You recall a Russian proverb, "Once is accident, twice in conspiracy!" as you arrive at the 300 yard berm. You measure the target there, and the 1 MOA triangle is 3 inches across at 300 yds. You're starting to wonder if you really need to go all the way to 1000 yds, because as you measure the 1 MOA triangle at the 500 yard berm, it's 5 inches across. So you come to learn, that the 1000 yard berm will be 10 inches.
You are so convinced of this fact that you decide to memorize a handy rule: 1 MOA is 1 inch at 100 yds. If I double the range, I double the width. If I triple the range, I triple the width.
I will, from this moment onward, call "1 MOA is 1 inch at 100 yards", The Rule.
You stop again at 100 yards to measure the 1 MOA triangle again, and it's still an inch wide. Splendid!
You predict that, when you walk to the 50 yd berm, that the 1 MOA triangle will be 1/2 as wide.
Sure enough, when you measure, this is true: 1/2 inch. Somebody asks how wide it will be at 25 yds. Without thinking, your inner Rifleman utters, "1/4 inch!"
So, if your target is three times as far away as The Rule, your 1 MOA triangle is three times as much as 1 inch. And if your target is 1/4 as far away as The Rule, your 1 MOA triangle is 1/4 of one inch.
Now you're seeing things with Rifleman colored shooting glasses. When asked how tall you are, you reply, 'Well, I'm 70 MOA at 100 yards, I am also 35 MOA at 200 yards. I am only 7 MOA tall at 1000 yards, however.
Intrigued, the questioner asks, What is the Rifleman's standard of accuracy? is it a three inch group? How about a 5 inch group?
You reply, "You haven't told me enough information to answer that question. Riflemen, you see, measure accuracy in terms of minutes of angle, not by inches alone. The proficient Rifleman prints 4 MOA groups or smaller up to 500 yards. That means a four inch group at 100 yards. And a 1 inch group at 25 yards."
And so it goes. You know The Rule, you can figure the angular size, in MOA, of any target or group.
Back to the SKS windage clamp. If you push the front sight drum with the screw, you move it 7.6 MOA every time you turn the screw one time.
And, since this is an adjustment tool, the same information is stamped on the clamp that fits the SKS front sight elevation screw. In that case, every time you move the front sight elevation screw one full turn, you move the point of impact 5.4 MOA.
See, Barbie was wrong.
Minor but important quibble.
"1 MOA is 1 inch at 100 yards" = True
"1 MOA is 1 inch per 100 yards" = Rifleman's definition of MOA
Ditch the first one, memorize and teach the second. It makes it so much easier for Appleseeders who are being exposed for the first time.
SoM
Thanks,Francis. If I read this like a 100 times...I might remember it...1 MOA = 1" per 100 yards.. ++)
Quote from: Fred on September 10, 2008, 11:59:13 AM
Width of the front site should be the width of your target at the specific max range which is still within Battlesight Zero distance.
For most rifles, that translates to 7 MOA as the correct width of the front sight, so that you can use it as a range-finder at unknown distances. Any man-size target as wide or wider than the front blade would be within BSZ distance and no need to fuss with sight elevation changes/holdovers. Simply take the shot. Clean, simple, easy.
If you have a preference for a thinner front sight blade, 4 MOA would work as well. ;D
A Rifleman "wastes not, wants not."
Having an integral range-finder which works right at the moment of acquiring sight pic is a wonderful asset to have.
Fred wouldn't this cover 35 inches at 500 yards which would be 15 inches wider than the average man's torso?
It's the height of the post, in MOA, that ranges targets. Not the elevation to which it happens to be screwed into the front sight assembly on any given rifle. The only purpose of the threads on the post, and the position of the post in the front sight assembly, is to adjust the zero of the rifle. Independently of zeroing, the width and/or height of the square faced post is key to ranging. I don't know if the military uses differently sized posts for rifles and carbines, but once you know the angular size, whether width or height, of your post on your rifle when your eye is in firing position, you have enough information at that point to estimate ranges.
That's not just a front post folks have on their rifles, it's also an angular measuring instrument, capable of measuring along two axes: the horizontal and the vertical.
How do you range targets with the sight? You scan the target zone and say to yourself, "this front sight of mine is 15 MOA wide. That measures 15 inches at 100 yards, 30 at 200, 60 inches at 400 yds... that redcoat yonder is as tall as my front sight is wide. That places him at 400 yards since he's 5' tall and my front post sweeps 5' at 400 yds. Dial elevation to 4.
If you can decide how many inches in dimension something is you want to range, and you know the MOA of your angular measuring instrument (uh, your front sight), you can neatly range the target by working from Inches to Minutes of angle to, on a sighted in rifle, the best place to take the shot on your elevation dial.
1) check, I get 15 MOA, and that's provided your eyeball is 18.75" away from post in firing position.
2) Don't know- I'm inclined toward uniform, dark, flat value across the entire front sight face. That's a versatile setup. You can observe a phenomenon called simultaneous contrast with two adjacent, light/dark valued objects; look at the edge effect between the boundary of overlapping black and white objects. The cost of the experiment is cheap, $5 for a front post.
3)If the 200 (large diameter) aperture is up, and the drum is at 3, the front post of the rifle should be sighted such that you strike your target at 200 yds. And, when you flip the aperture to the small diameter, with the drum still at 3, you are now sighted for 300m. I don't know if the military uses a different elevation drum for those arms with barrel lengths shorter than the standard A2 length. If you have an A2 source elevation drum, though, point of impact may diverge from the drum setting more than you'd like at the farther ranges.
You guys are complicating up what should be simple. Appleseed is about keeping things simple.
"Shoulder width" or 20 inches is the most likely target you'll range on. Hence the width of the front sight is usually more of interest than the height.
Figure the width in MOA and figure at what distance that translates into 20 inches, is simplest. Then when the target is greater than your front sight, it's closer than that distance; if smaller, it's farther.
Quote from: Tom Russell on April 21, 2009, 09:46:14 PM
Quote from: Fred on September 10, 2008, 11:59:13 AM
Width of the front site should be the width of your target at the specific max range which is still within Battlesight Zero distance.
For most rifles, that translates to 7 MOA as the correct width of the front sight, so that you can use it as a range-finder at unknown distances. Any man-size target as wide or wider than the front blade would be within BSZ distance and no need to fuss with sight elevation changes/holdovers. Simply take the shot. Clean, simple, easy.
If you have a preference for a thinner front sight blade, 4 MOA would work as well. ;D
A Rifleman "wastes not, wants not."
Having an integral range-finder which works right at the moment of acquiring sight pic is a wonderful asset to have.
Fred wouldn't this cover 35 inches at 500 yards which would be 15 inches wider than the average man's torso?
Tom, guess a late answer is better than none at all - just saw your post.
Yes, 7 MOA covers 35 inches at 500 yards - but you don't care - as the important thing is that 7 MOA defines the max battlesight zero - the max range you can, with your 275/300 yard zero on, aim dead on and expect to hit the target.
Any target as wide or wider than your front sight, you forget about range, and take the shot. Only if the target is smaller than the width of the front sight blade do you have to range-estimate.
So it really simplifies things...for the rifleman in the field...
That's why the 6'oclock hold comes in handy. ;)
The front sight is 2-3 wider than the woodchuck that I'm trying to center on it @150 yards. Gotta keep that apple on top of the fense post. lol, no really!
The 2.5 power Weaver that was on my 03A4 was the crosshair/post type scope. The milkjugs of water were 1/3 the width of the top of the post.
Just center it and hold, it'll work if you use it right.
This shows pretty much what I have on all my Russian rifles;
(http://www.mojosights.com/images/SightCompWeb.jpg)
Far right is my Mosin, middle is my AK, far left how they started out. I am just in love with these Mojo sights and yes I know my current Mosin is a high light sight but it just works so well.
Funny you posted that.
We had 2 shooters using homemade Mojo sights on their 10/22's this past weekend. Other than the coarse adjustments, they worked well.
Well enough for "dad" to shoot a 220 on Saturday. The event was New Bremen, NY.
Homemade???
How'd they manage that?
I'd like to put better sights on my SKS, but I don't want to put 50 bucks into the mojo's.
Hey Dirty Bill.
Her is teh key to remembering the MOA.
An MOA ian't 1" at 100 yards it is 1.0471996" at 100 yards. After you cuss yourself silly trying to remember that figure, 1" is easy ;)
Sam
*whisper voice on*.....to use the front-sight post as a ranging device requires that sometimes, the muzzle might be pointed at something that mightn't need to be destroyed within the next 3-4 seconds.....so, well....don't let the neighbors see you estimating range that way *whisper voice off*......
actually, the front-sight range estimating can be a useful tool while developing your distance-eye....or further convincing your neighbors that you are, indeed, depending on your zipcode and demographic, either a loon, or a guy who takes his riflery seriously
Quote from: Geddys Uncle on July 03, 2009, 11:30:37 PM
*whisper voice on*.....to use the front-sight post as a ranging device requires that sometimes, the muzzle might be pointed at something that mightn't need to be destroyed within the next 3-4 seconds.....so, well....don't let the neighbors see you estimating range that way *whisper voice off*......
actually, the front-sight range estimating can be a useful tool while developing your distance-eye....or further convincing your neighbors that you are, indeed, depending on your zipcode and demographic, either a loon, or a guy who takes his riflery seriously
If my neighbor across the street knew how many times I've "shot" the license plate on his truck, he would be very unhappy with me :)
Quote from: gjwilliamsjr on July 04, 2009, 12:12:53 AMIf my neighbor across the street knew how many times I've "shot" the license plate on his truck, he would be very unhappy with me :)
:o :o :o ::) no contact, no foul......when the subatomic physics guys complain that the neutrinos are starting to leave holes, your neighbor will have bigger things to worry about. :D
I got the chance to do some real distance shooting over the weekend. I posted two 20" silhouettes out on two different hills, one further than the other.
When I got back to my firing point, I tried a range estimation.
The first silhouette was just under my front sight width. I had done some math the night before, and according to my sight radius and sight width (.072") I have an 8moa front sight. This makes sense. A 20" target at 250 meters will be 8 MOA wide. However, the closer target was between 1/2 and 3/4 the size of my front sight. I clicked up 2 clicks past my 200 yard setting and let fly. (Now I realize the mistake and should have clicked up more)..
I then shifted NPOA to my further target. It took up about 1/3 of my front sight. I clicked up to my 600 yd zero and fired a five round group. I called all the shots good. No dirt splashes.
Unfortunately, upon checking the targets, the further silhouette had no holes. Not even in the surrounding cardboard. I could find no scrapes in the dirt as it is thick prairie grass. Hmm..
The closer silhouette also had no holes.. In the dirt in front of the target were my bullet scrapes, aprox 40 inches below impact zone. So, I had underestimate my range... It was strange because I felt like this target was only 250 meters or so away, and I thought clicking to 300m would be overkill. I also thought the further away silhouette was only 500m away. Of course, this could not be the case if it took up 1/3 of my front sight, (2and2/3 moa)
Feeling somewhat discouraged (and out of time) I packed up and considered buying a range finder.
Maybe the landscape threw me off. It was a series of rolling hills (Iowa)... Maybe I wanted to believe that 500m was really really far off, when it didn't seem so. Maybe my calculations are wrong.
I like the idea of having the skill to do the job without fancy equipment. Of only needing to have my rifle to make shots. . . But at this point, it seems too chancy.
It seems that making estimations like "my target is 1/3 of my front sight" is very prone to mistakes. Perhaps this can be corrected by doing more unknown distance shooting.
Thoughts?
3/4 (6 moa) of your front sight is 330 meters distant. (20" / 6moa = 3.3 x 100)
1/2 (4 moa) of your front sight is 500 meters distant. (20" / 4moa = 5 x 100) If 20" is full width at 250(BSZ), half the sight is 2x the range or 500.
1/3 (2.67 moa) is 750 meters. (20" / 2.67moa = 7.5 x 100)
My scope has a built in moa range finder. It works amlost identical to your front sight. Be patient and practice as you almost have it. I take my laser range finder with on exercises to double check my work.
I've taken my rifles out to the 25m range in the pasture & looked at a QDAQT. Using the different size targets tells me at what range the front sight with equals 20 inches/4 MOA.
Guy
QuoteI got the chance to do some real distance shooting over the weekend. I posted two 20" silhouettes out on two different hills, one further than the other.
When I got back to my firing point, I tried a range estimation.
The first silhouette was just under my front sight width. I had done some math the night before, and according to my sight radius and sight width (.072") I have an 8moa front sight. This makes sense. A 20" target at 250 meters will be 8 MOA wide. However, the closer target was between 1/2 and 3/4 the size of my front sight. I clicked up 2 clicks past my 200 yard setting and let fly. (Now I realize the mistake and should have clicked up more)..
For quick mental math purposes, let's equate yards with meters. Your 8 MOA front sight should match the 20" target width at 250m... 8 MOA times 2.5 "/MOA is 20 inches.
Working from the known to the unknown, we know now that the 8 MOA front sight, the 20" target, and 250 meters are a matching set of information, a "battle sight zero" if you will.
The near target was between ½ and ¾ the width of the front sight. So, the target range is estimated as
(the reciprocal of 1/2) times 250 meters, which is 2 * 250 meters, for a range estimate of 500 meters. Not going to hit that with a 200 m elevation plus two clicks. The come-ups for a 30 cal from 250m to 500m would be roughly 1 ½+ 4+4 for a total of 9 ½ clicks above the 250m setting. So 200m elevation plus two clicks wasn't enough.
And if that near target was ¾ the width of the front post, the range is estimated as (reciprocal of ¾) times 250 meters, or 4/3 times 250 meters or 333meters. The come ups from 200m to 333 for a 30 cal rifle would be I'd estimate 3 +2 for a total of 5 clicks.
So still a little low. The range estimation is only as good as your set of assumptions (front sight width, target size) and the shooter's judgement (ratio of target to front sight width). This is a give and take exercise, at the expense of high precision, the simple fractions give you a chance to estimate range quickly by mental calculation. If you have the luxury of time, and a pocket calculator, you can assign the target a more precise ratio to the front sight post. But the idea here is not to establish range with the precision of a laser, but to estimate range with an educated guess with such tools (front sight and brain) as are available to any person who shoots a rifle.
QuoteI then shifted NPOA to my further target. It took up about 1/3 of my front sight. I clicked up to my 600 yd zero and fired a five round group. I called all the shots good. No dirt splashes.
That was a rather far target. How far: The target was 1/3 the width of the front post, so its range is (reciprocal of 1/3) times 250meters which is 3 times 250 meters, which is 750 meters away. With a 600 yd zero, (let's lump yards and meters into the same bag for quick mental math purposes) the come-ups to get from 600 yds to 750m would be 6 + 4 for a total of 10 clicks. So 600 meters/yds needed 10 more clicks to get to 750. If you were hitting 10 clicks low at 750m that's 75 inches low.
QuoteUnfortunately, upon checking the targets, the further silhouette had no holes. Not even in the surrounding cardboard. I could find no scrapes in the dirt as it is thick prairie grass. Hmm..
The closer silhouette also had no holes.. In the dirt in front of the target were my bullet scrapes, aprox 40 inches below impact zone. So, I had underestimate my range... It was strange because I felt like this target was only 250 meters or so away, and I thought clicking to 300m would be overkill. I also thought the further away silhouette was only 500m away. Of course, this could not be the case if it took up 1/3 of my front sight, (2and2/3 moa)
Feeling somewhat discouraged (and out of time) I packed up and considered buying a range finder.
Maybe the landscape threw me off. It was a series of rolling hills (Iowa)... Maybe I wanted to believe that 500m was really really far off, when it didn't seem so. Maybe my calculations are wrong.
Your feeling overruled your math. You're learning valuable facts about your perception, your rifle and bullet trajectories at full distance.
If you worked it from the "battlesight zero", or known set of information for your rifle sight, your particular target, and that target's size relative to your sight post, you would have been a lot closer. Try it again with a pencil and paper, out on the range with these same targets. Take a sight picture, establish the target to sight ratio, estimate the range, and dial it in. You're not generating magic numbers, just the best places to start. Keep at it.
QuoteI like the idea of having the skill to do the job without fancy equipment. Of only needing to have my rifle to make shots. . . But at this point, it seems too chancy.
The estimate is only as good as your set of assumptions (sight width, target width) and judgement (target to sight ratio). Persist. You underestimated the ranges, maybe even overrode what the math and the sight picture were telling you. Trust the sight picture and math, they will diligently report the facts, and then the mind can get in line.
QuoteIt seems that making estimations like "my target is 1/3 of my front sight" is very prone to mistakes. Perhaps this can be corrected by doing more unknown distance shooting.
Most definitely, do more distance shooting, learn or test something each time. This is the best fun.
QuoteThoughts?
I think you should do some more of this.