No. Not that kinda dope. This is the Rifle Knowledge Bank, not Deals and Steals. :slap:
Anyway, the MN crew is runnin' a line at the SHTF shoot coming up on Sat. The idea is to run 'em up against some targets as one of the competitions, but primarily as promo op - Is their a better way to force them to find thier Max effective range?
The original concept involved having shooters shoot a 25 m CAQT - 20 rounds, 2 minutes - see how they sized up. Being that time and space is limitted, this was chosen to be the most effective means to give folks a quick breifing and run 'em through. Scores being added for the events overall competition grading - or something along those lines.
SPEED BUMP
This last week, we got diverted to a 52 foot range, instead of the original 25 m... Yeah, it blows, I know. IAO and we have a COF and targets for essentially a 50 ft CAQT. While Kosciusko is busy working on logistics. Mr. SI got to thinking...
Will anyone even be on target at 17 yards, if they're zeroed at a more practical range? How would it look if the guys with the smallest targets made them shoot at an unusual distance without sighters and without a notion of what to adjust those sights to?
Does anyone have any experience with this? 1 moa @ 17yds is about 1/6in. Simple enough. What I'm looking for are the approximate come-ups for 17yds, in a two basic forms. High sight over bore rifles(AR's/scope), and low sight over bore rifles(m1/m1a/irons sights). People will be bringing a hodge-podge assortment of equipment for sure, but I think it would be prudent to give them enough of an estimate to get close.
So does anyone have this dope? Confirmed and/or theoretical? I'd be fine if someone could simply tell me where the bullet crosses the POA again. Then one could just say; You have an AR? Set it to your 600 yard zero.
Would .22lr's show a real noticible difference?
Like I said, theoretical works fine for this purpose - That's for you ballisticians out there. But I know there's a few of you who like to tinker at different ranges as well.
Thank you in advance,
Aftermath
P.S. Perhaps, I'm over thinking this and a practical zero will be close enough at 17yds...
Quote from: AFTERMATH on September 20, 2012, 10:47:12 PM
P.S. Perhaps, I'm over thinking this and a practical zero will be close enough at 17yds...
If anything you're going to be low, since the bullet is still rising, but not by very much.
Yes, you will be on the paper if they have a BSZ.
Quote from: Edheler on September 20, 2012, 10:52:11 PM
Quote from: AFTERMATH on September 20, 2012, 10:47:12 PM
P.S. Perhaps, I'm over thinking this and a practical zero will be close enough at 17yds...
If anything you're going to be low, since the bullet is still rising, but not by very much.
Yes, you will be on the paper if they have a BSZ.
Yeah, I know it's gonna be low... At least with anything larger than a BB gun. And yes they'll be on paper... But are we talking on the target, on the 3 ring, or on the 4 ring type low... 'D' targets scaled for this range. Then again, the size of the bullet will be large enough to compensate, perhaps. A .30 cal is going to be about 2 moa in dia. at this distance.
Honestly, I think most probably won't have over a 50 or 100 yard zero - That seems to be where most 'casual' shooters sight in at.
Quote from: Edheler on September 20, 2012, 10:52:11 PM
Quote from: AFTERMATH on September 20, 2012, 10:47:12 PM
P.S. Perhaps, I'm over thinking this and a practical zero will be close enough at 17yds...
If anything you're going to be low, since the bullet is still rising, but not by very much.
Yes, you will be on the paper if they have a BSZ.
Correct. You're going to be low approximately 1/4 the distance between the bore axis and sight axis. For a typical LTR this will be up to about 1/2", call it 3 MOA or less. On paper but not precise enough to make Rifleman.
Quote from: Rocket Man on September 20, 2012, 11:04:38 PM
Correct. You're going to be low approximately 1/4 the distance between the bore axis and sight axis. For a typical LTR this will be about 1/2", call it 3 MOA. On paper but not precise enough to make Rifleman.
We're within arguing distance. I would probably say 2 MOA. I suspect we're thinking about different LTR configurations though.
Quote from: AFTERMATH on September 20, 2012, 11:00:21 PM
Yeah, I know it's gonna be low... At least with anything larger than a BB gun. And yes they'll be on paper... But are we talking on the target, on the 3 ring, or on the 4 ring type low... 'D' targets scaled for this range. Then again, the size of the bullet will be large enough to compensate, perhaps. A .30 cal is going to be about 2 moa in dia. at this distance.
Honestly, I think most probably won't have over a 50 or 100 yard zero - That seems to be where most 'casual' shooters sight in at.
There really are too many variables, but for a centerfire rifle zeroed at 100 yards, I would expect them to be 6-8 MOA low. This is without putting all of the data into a ballistics calculator. (Just math in my head.)
most of the shooters will have AR15s in 5.56 , a minority will carry AK series in 7.62x39
there will be some oddball rifles as well, but I can't worry about that at this time
ARs will most likely be in M-4 config, a combination of fixed and flip-up iron sights, large numbers of ACOG, EOTECH, HOLOSIGHT
I asked the organizers 3X for a 25 meter range and we got what we got
Thanks to all for their help, thanks to AFTERMATH for noticing this. I was too busy running around gathering promo and people.
It should be an interesting day for all concerned.
Kosciusko
I have a really neat ballistic calculator on my Android. It is by STRELOK and is free. I believe that they have them for the IPhone also.
Pick your zero distance, load... and it will calc your come up's errr....come downs?
2CL
except I have a DumFone (TM) that doesn't even sport a camera :-[
This is different, but why don't you use TV Targets? Ten rounds in thirty seconds? It is a hit count target so there is no real scoring involved. They are a fun challenge and the message written on them is what Appleseed is about. At fifty-ish feet they should be big enough to hit, small enough to be a challenge, and I would not really worry too much about the bullet drop at that range. That is just a thought. I know you Minnesota folks really have your stuff together and will handle it all really well.
Alex
Appleseed is one stage in of the Coonan Arms challenge, they wanted points to be totaled towards picking prize winners
I wanted to use greencoats, but the distance is too short, the shooter would get a false sense of their skill level.
The free targets are geared towards 50 feet and easily scoreable, cheap to produce, and use a "D" silhouette.
I wanted things as Apple-seedish as feasible. This way, they get standing, seated/kneeling, prone, plus time constraint of 75 or 90 seconds, haven't decided on a time yet. Probably 90 seconds.
This is the first time out the gate for this sort of thing (for us anyway) , we will revise based on our experiences Saturday after the 300 shooters are done. for full details, search for the thread "zombies and Appleseed"
Next year, we do the dpms outbreak omega gathering, 800 ( eight hundred ) shooters in one day.
k
You will be close to your 500 yard zero with a .223.. Your 25M zero will put you near 1" (6 minutes) low at 17yards. AR15 iron sights are 2.6" over bore.
Quote from: AFTERMATH on September 20, 2012, 10:47:12 PM
P.S. Perhaps, I'm over thinking this and a practical zero will be close enough at 17yds...
With an intermediate zero, the most you should be off is 2" (12 minutes) low which is about what a 100 yard zero would give you. In other words, you will be on paper with a .223 at 17 yards regardless of what your current zero is. You will also be on paper with a .22lr so it will not a big deal to make a zero shift from 25M to 17 yards.
http://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi
Great online ballistic calculator. I just picked a Speer 62gr fmj/bt bullet out of their library. Put in a reasonable muzzle velocity and the right sight height. Then you can get range cards listing where the trajectory will be at 17yd with a 25, 50, or 100yd zero and approximate comeups.
You are 2/3 the distance to your 25m zero, so you will be 1/3 of your sight-to-bore height low.
A scope that is 2" above the bore and zeroed for 25m, will need to have about 2/3 of an inch added to its zero to intersect with the line of sight earlier. 2/3 of an inch at 17meters, where each MOA = 1/6 of an inch comes out to 4MOA increase in elevation.
A low-sighted M1 or M14 or Mini only has about 1 inch between sight plane and bore. You need 1/3 of an inch added to the trajectory at 17 yards, which comes out to 2MOA since each MOA = 1/6 of an inch.
DumFone approved Ballistic Calculator. I know you have internet so :
http://www.shooterscalculator.com/ (http://www.shooterscalculator.com/)
I would run the numbers for you, but alas I do not own a black rifle and don't know silly things as sight height above bore or MV etc.
Call me old fashion but I prefer the 30.06 to the .556 when I have to do the AT&T thing.
The Promo Target 15 yds should serve you well.
http://appleseedinfo.org/smf/index.php?topic=7406.msg69802#msg69802 (http://appleseedinfo.org/smf/index.php?topic=7406.msg69802#msg69802)
2cl
Shoot a squares target, adjust sights, shoot CAQT. For 62 gr. the zero distance would be around 400 yards (as opposed to 275-325 depending on barrel length etc). For an M1 the zero would be around 275 yards.
Here is an online ballistics calculator. My assumptions were (AR. 62 gr, .4 BC, 2700 fps, zero of 400) and M1 (150gr, .4 BC, 2600 fps)
You can reverse engineer using the ranges with the Hornady Ballistics software http://www.hornady.com/ballistics-resource/ballistics-calculator
Your best bet is to shoot a squares and measure the distance and then adjust for clicks. If you knew your zeroes from a bottomed out sight, it would be relatively simple to count up for this.
Good luck.
The calculator shown in a previous post puts you 4.5 MOA low at 17 yards with a 25 yard zero. But I doubt that you will have too many 25m zeros at the zombie shoot.
Quote from: jmdavis on September 21, 2012, 02:12:12 PM
The calculator shown in a previous post puts you 4.5 MOA low at 17 yards with a 25 yard zero. But I doubt that you will have too many 25m zeros at the zombie shoot.
I doubt that as well - There's no real way of telling what kinda sighting they're coming in with so I figured this would be a great way to start. There's no time for sighters or for us to look up balistics tables. But I figured we could get an approx. idea just asking them where they're sighted in at.
So, for instance they show up with an AR/AK sighted in at 100 yards, Add ~5moa to get to 300 yard zero, add an additional 4-6moa for the theoretical 17/400-500. - Or we just tell 'em to set their sights for 400-500...
Low sight radius we could could tell them to set their sights for 275.... - Or ~5 minutes over 100.
If they're sighted in for 50, have them cut their adjustments from 100 in half....
Does this seem about right?
Thanks guys!
Off the top of my head, for any distance up to about 100(perhaps 150) yards, I would think this equation might work as we can neglect gravity a bit, at this point - Let me know if this is right...
[(zero range in yards) / 17] X (sight height over bore) = (correction in inches)
Correction in inches X 6 = correction in minutes
On a side note, I've got an old TI-89 calculator that I believe is still functional - does anyone have a good ballistics program for that?