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Sight Radius Info Needed

Started by ashrn03, January 02, 2009, 12:22:54 AM

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ashrn03

I'm preparing a listing of sight adjustment data for rifles which might be used at Appleseeds.  (I'm doing this because I made the mistake of mentioning I had data for some rifles that weren't on the list handed out at a recent IBC and was promptly tasked with updating that list  &)) Anyway, I'm looking for the sight radius for the following rifles which for which I don't have info:

AR-15 20" barrel (Standard M16A1 or A2 configuration)
Enfield Mk III No. 1
Enfield No. 4 Mk 1 or 2
Enfield No. 5 Mk 1

I measure from the rear of the front sight blade to the rear of the peep/notch.  Thanks for your help.   
The way to herd cats is to offer treats

wcmartin1

Quote from: ashrn03 on January 02, 2009, 12:22:54 AM
AR-15 20" barrel (Standard M16A1 or A2 configuration)

My A2 with a 20" barrel, believe it or not, has a 20" sight radius.  :o
"Unhappy it is, though, to reflect that a brother's sword has been sheathed in a brother's breast and that the once-happy and peaceful plains of America are either to be drenched with blood or inhabited by a race of slaves.  Sad alternative!  But can a virtuous man hesitate in his choice?" - George Washington - from a letter to a close friend after the events of April 19, 1775

"There is no nation on earth powerful enough to accomplish our (the United States) overthrow.  Our destruction, should it come at all, will be from another quarter.  From the inattention of the people to the concerns of their government, from their carelessness and negligence, I must confess that I do apprehend some danger.  I fear that they may place too implicit a confidence in their public servants, and fail properly to scrutinize their conduct; that in this way they may be made the dupes of designing men, and become the instruments of their own undoing." - Daniel Webster, June 1, 1837

Francis Marion


Old Dog

Here we go again.  I've tried posting this twice and it either doesn't go through or I get a message saying I've already posted it.

ashrn03, its some of what you asked for and more than what you asked for.  Hope you can use the info or the ideas.

edited - didn't go through again, hope it "sticks" with this edit
"The rifle itself has no moral stature, since it has no will of its own. Naturally, it may be used by evil men for evil purposes, but there are more good men than evil, and while the latter cannot be persuaded to the path of righteousness by propaganda, they can certainly be corrected by good men with rifles."

—Jeff Cooper, The Art of the Rifle

ashrn03

Quote from: Old Dog on January 02, 2009, 01:49:27 AM
Here we go again.  I've tried posting this twice and it either doesn't go through or I get a message saying I've already posted it.

ashrn03, its some of what you asked for and more than what you asked for.  Hope you can use the info or the ideas.

edited - didn't go through again, hope it "sticks" with this edit


Thanks for the file.  I've had the same problem trying to load .jpg photographs.  Finally gave up; TaosGlock posted them for me using software I don't have. 
The way to herd cats is to offer treats

ashrn03

Bump.

Still looking for sight radius info for Enfield Mk III No. 1.  Anybody got one?
The way to herd cats is to offer treats

yellowhousejake

My 1914 No1 MK III measures 19 7/16"  I can give you elevation measurements after this weekend as I am working up my SMLE for RBC in October.

DAve
I have removed my email from my profile to stop the mod reports. If you need a Libertyseed scheduled you will now have to contact me on the Libertyseed forum.

YHJ

ashrn03

#7
The No. 1 Mk III has a yardage tangent rear sight with the increments marked in yards.  While I have no specific 'come-up' info (in MOA) for your rifle, they should be in the ballpark for the 308 Win within the ranges you'll be using the 303.  Standard come-ups for 308 are (from 100 yards) 3, 3, 4, 4, 5.  In other words, moving your rear sight from 100 to 200 should raise the impact around 3 MOA; from 200 to 300 another 3 MOA; from 300 to 400 another 4 MOA, and so on.       
The way to herd cats is to offer treats

yellowhousejake

I have never fired beyond 200 yards with any SMLE. I Plan to actually work out the measured height of sight adjustment and the resulting MOA. I suspect it will be "close enough" for Appleseed to the 308.

The official British sighting target provides the following when checked at 25 yards with Mk VII ammo, 174gr bullet at 2440 FPS.

200 yard = 3/4" above POA
300 yard = 1 3/4" above POA
400 yard = 2 1/2" above POA
500 yard = 3 3/4" above POA
600 yard = 5 1/4" above POA

A proper trajectory chart should fill in the gaps.

DAve
I have removed my email from my profile to stop the mod reports. If you need a Libertyseed scheduled you will now have to contact me on the Libertyseed forum.

YHJ

ashrn03

yellowhousejake: 

It looks like you can use your inches-minutes-clicks knowledge to obtain your come-ups from your sighting target data.  I suspect there's a few rounding errors since the increments aren't sequential.  (Have you been to an Appleseed yet?) 
The way to herd cats is to offer treats

yellowhousejake

Quote from: ashrn03 on June 13, 2009, 12:38:01 AM
yellowhousejake: 

It looks like you can use your inches-minutes-clicks knowledge to obtain your come-ups from your sighting target data.  I suspect there's a few rounding errors since the increments aren't sequential.  (Have you been to an Appleseed yet?) 

Should be able to, a quick measurement last night showed each division (25 yards) on the SMLE would give 1.45 MOA adjustment. On the fine adjust thumbwheel, .029 MOA. Only shooting will confirm for certain. I watched an Appleseed on Patriots day but I could not attend all day each day and shoot. My youngest son and I are confirmed for the June shoot at Cloverdale Indiana, and I have vacation scheduled for the October RBC in Missouri.

I dry fire at least three times a week and have since March, my son and I have also live fired a few times since he got his LTR ready. When I confirm the MOA settings for the SMLE I will let you know. I suspect my calculations are correct, certainly enough for a shooter to "get in the ballpark".

DAve
I have removed my email from my profile to stop the mod reports. If you need a Libertyseed scheduled you will now have to contact me on the Libertyseed forum.

YHJ

yellowhousejake

If my math is correct, this is what I have for an SMLE.

19.437 sight radius
lowest sight setting = 26/64
1000 yd sight setting = 46/64
sight movement = 20/64 or .03125
25 yd sight encrements is 40 steps to 1000 yds
.03125 movement by 40 steps = .0078 movement per step
3438 / 19.437 = 176.87 total MOA movement
176.87 * .0078 = 1.379 MOA per step


303 British 174gr/2240fps with 200 yard zero (from shooting times)
Range   100        200       300     400    500
--------------------------------------------
Inches   +2.8     0       -11.2  -32.2  -64.9
MOA          -3        0        4       8        13
Comeups    ?          0        4       4        5

Looks pretty close, so all I need to do recalc for a 100 yard zero and then figure my comeups. I should be able to also get my BSZ as well.

Does this look correct?

DAve
I have removed my email from my profile to stop the mod reports. If you need a Libertyseed scheduled you will now have to contact me on the Libertyseed forum.

YHJ

ashrn03

I'm once again updating a sight adjustment table for rifles you may see at Appleseeds and need the sight radius info for the following rifles.

H&K 93
Mosin-Nagant 91/30, M38 (a carbine, no bayonet lug), M44 (a carbine w/side folding bayonet)
Ruger Mini-14

I measure from the rear of the front sight blade (or front sight post) to the rear of the peep/notch.  Thanks for your help. 
The way to herd cats is to offer treats

slim

Begging your pardon, but why would a Rifleman need to know the sight radius of any given rifle?

CharlieHotel

The A2 sights were designed for a rifle length gas system. As you change the sight radius, the amout of MOA per click changes. Decreasing sight radius increases the change a single click will make. If you don't know how many MOA per click, how do you make accurate sight adjustments?


CH
"A good plan executed perfectly is better than a perfect plan executed poorly"

"As steel sharpens steel, so one man sharpens another"

"It's not the dope 'ON' the rifle, but the one behind it!" - Unknown PMI, Parris Island, SC 1984

So speak and so act as those who will be judged by the law of Liberty.
For Judgement comes without mercy for those who have shown no mercy, Mercy shall triumph over judgement.
James 2:12-13

ashrn03

Quote from: slim on December 21, 2011, 05:04:30 PM
Begging your pardon, but why would a Rifleman need to know the sight radius of any given rifle?

In my table I use the sight radius to calculate the distance the sights have to be moved per MOA of bullet movement on the target.  It's directly useful if you have to drift a front or rear sight and it's the basis for making calculations involving screw pitch adjustments.   
The way to herd cats is to offer treats

slim

Quote from: ashrn03 on December 21, 2011, 05:52:58 PM
Quote from: slim on December 21, 2011, 05:04:30 PM
Begging your pardon, but why would a Rifleman need to know the sight radius of any given rifle?

In my table I use the sight radius to calculate the distance the sights have to be moved per MOA of bullet movement on the target.  It's directly useful if you have to drift a front or rear sight and it's the basis for making calculations involving screw pitch adjustments.   
And that's something you're instructing at Appleseeds?

ashrn03

Quote from: slim on December 22, 2011, 08:26:22 AM

And that's something you're instructing at Appleseeds?

No, the table (spreadsheet) of sight adjustments is intended as a reference document for Instructors.  So far it has info for over 30 firearms or model variations, including 4 barrel lengths of 10/22's for both factory sights and Tech Sights.  It's also a work in progress and hasn't been reviewed by higher ups.  I originaly put the table together for my own use and while it's complete there may be too much information for casual users.  The plan is eventually post at least some form of the info on the TIPS page. 



 
The way to herd cats is to offer treats

Reddot

Merry Christmas Paul,
I have an M1938 Moisin and an original Model 1891; I'll measure them this weekend and send you the data.
Chuck

slim

Quote from: ashrn03 on December 22, 2011, 02:21:33 PMNo, the table (spreadsheet) of sight adjustments is intended as a reference document for Instructors.  So far it has info for over 30 firearms or model variations, including 4 barrel lengths of 10/22's for both factory sights and Tech Sights.  It's also a work in progress and hasn't been reviewed by higher ups.  I originaly put the table together for my own use and while it's complete there may be too much information for casual users.  The plan is eventually post at least some form of the info on the TIPS page.
Is there some formula you're using to figure the MOA/click using the sight radius?

Roland

I would be interested in knowing what the exact MOA on a 16'' midlength AR is. It seems to somewhere around 1/2 per click,, but knowing the exact clicks would make me feel better!

Roland
The doorway to freedom is framed by the muskets that stood between a vision of of liberty and absolute anarchy at a place called Concord Bridge--Charlton Heston, 1997

"Be a man of principle. Fight for what you believe in. Keep your word. Live with integrity. Be brave. Believe in something bigger than yourself. Serve your country. Teach. Mentor. Give something back to society. Lead from the front. Conquer your fears. Be a good friend. Be humble and be self-confident. Appreciate your friends and family. Be a leader and not a follower. Be valorous on the field of battle. And take responsibility for your actions. Never forget those that were killed. And never let rest those that killed them." -- Major Douglas Zembiec

ashrn03

#21
Quote from: slim on December 22, 2011, 11:48:06 PM
Quote from: ashrn03 on December 22, 2011, 02:21:33 PMNo, the table (spreadsheet) of sight adjustments is intended as a reference document for Instructors.  So far it has info for over 30 firearms or model variations, including 4 barrel lengths of 10/22's for both factory sights and Tech Sights.  It's also a work in progress and hasn't been reviewed by higher ups.  I originaly put the table together for my own use and while it's complete there may be too much information for casual users.  The plan is eventually post at least some form of the info on the TIPS page.
Is there some formula you're using to figure the MOA/click using the sight radius?

Uh-oh.  That's a very reasonable question (the short answer, by the way, is "Yes") but if I answer it in this thread we're going to drift off topic and the answer will be lost for the ages.

A little background here.  If you read the first post on this topic it noted that I openned my mouth at the wrong time at an IBC and, in true RWVA/Appleseed fashion, was promptly handed a task to complete.  While compiling the data I made many 'exciting' discoveries, not all of which agreed with information previously published on the forum or in manuals.  This meant there was either a flaw in my algorithms, that the published data was based on different information than I was using, or that I had simply screwed up somewhere.  This is why technical articles need 'peer review' before publishing.  About this time I also mentioned what I was doing to Fred, who turned out to be less than enthusiastic about the project.  His objection was that the table would be providing Instructors with "fish" instead of "teaching them to fish".  He wasn't just picking on me, he's made this same observation in other posts.  This actually fits in with my discoveries on conflicting data: I could post what I had in a table, but what about new models or variations?  So the answer to your question is actually a "teaching them to fish" topic.  Not wishing to reinvent the wheel, I did a quick search of previous topics in this forum and in the "Skill Sets of Shooting" to see if had been covered before.  The plan was to provide a link to something already posted.  I didn't find anything.  Rats.  So here's the plan: I'll write up a new topic answering your question and add the link to this reply.  Stay tuned.

12/26/11 Update

The new topic "Sight radius, MOA, and clicks" is now posted on the Rifleman Knowledge Board Trial Board  http://appleseedinfo.org/smf/index.php?topic=26930.0
The way to herd cats is to offer treats

ashrn03

Quote from: Roland on December 23, 2011, 02:21:28 PM
I would be interested in knowing what the exact MOA on a 16'' midlength AR is. It seems to somewhere around 1/2 per click,, but knowing the exact clicks would make me feel better!

Roland

OK.  We need a little more information about the rifle in question; I'm not sure what a 'midlength AR" is.  What is the sight radius? (as described in my 12/20/11 post above).
The way to herd cats is to offer treats

slim

Quote from: ashrn03 on December 24, 2011, 04:10:25 PM"teaching them to fish" topic.  Not wishing to reinvent the wheel, I did a quick search of previous topics in this forum and in the "Skill Sets of Shooting" to see if had been covered before.  The plan was to provide a link to something already posted.  I didn't find anything.  Rats.  So here's the plan: I'll write up a new topic answering your question and add the link to this reply.  Stay tuned.
Will do.

Do you guys tell people to zero then do 10 clicks, shoot a group, measure, do the math backwards and write it down? Around here, that seems to be the standard method of "teaching them to fish" and it works pretty well. Plus, it gives folks more of a chance to do IMC and also allows them to see the difference between different ammo in different rifles, conditions, etc. It's a very simple way for them to figure it out on their own. Simple enough to instruct as well.

Old Dog

All the numbers/tables, etc. are nice to have for reference but sometimes things don't "add up".

Going back to my M14 days in the late 1970's (yeah, I was a lucky guy, TRW 1490317 for almost four years was with me daily Monday through Friday) I had one freaky "does not compute" incident.  We sighted in at 25 meters (as usual).  When we went to the train fire range and the qualification range I didn't aim at the head at 300 meters to knock the pop ups down, I had to aim at the dirt just below the pop up.  It wasn't as bad up close but I still had to aim lower than normal.  Once in three years the ammo we had did not have the same trajectory it did the other years.  At that time/age it just seemed to me like the bullets came out of the barrel and climbed and climbed and climbed.  The next year things were back to normal.

Anyway, the moral of the story - take it to the range with your ammo and find out how many clicks you need.  Then, if you change ammo, do it again to be sure.

Making a table for reference and sharing it with the folks on the forum is a nice thing to do.  Thanks.
"The rifle itself has no moral stature, since it has no will of its own. Naturally, it may be used by evil men for evil purposes, but there are more good men than evil, and while the latter cannot be persuaded to the path of righteousness by propaganda, they can certainly be corrected by good men with rifles."

—Jeff Cooper, The Art of the Rifle

Wade

For what ever its worth
If memory serves me correctly every .008 change of the front sight on the m-1 garand is 1 moa change on the target,,,please correct me if I am wrong,I want to use this info to correct my rear sight as it is not centered and is off to one side .

Wade
Got Tired of looking for a Rifle Range So we Dug one up!
WOOF!
4 box's #1 the soap box#2 the letter box #3 the ballot box #4 the cartridge box, The founding fathers picked up the Cartridge box so that WE could use the first 3,,IMO If you don't use those 3 then you dishonour the founding Fathers !

JustJeff

I didn't see a reply posted for the Mini-14.  The radius on mine is 21 3/4"
Your version of "ineffective" does not necessarily reflect the truth....
Having been "ineffectively" taught to the Rifleman Standard and having been "ineffectively" taught to teach others to the Rifleman Standard, I believe I prefer the "ineffective" over the other choice.

ashrn03

Quote from: JustJeff on December 24, 2011, 11:31:05 PM
I didn't see a reply posted for the Mini-14.  The radius on mine is 21 3/4"

Bless you.  And have a Merry Christmas.

P.
The way to herd cats is to offer treats

boltgun71

Quote from: Roland on December 23, 2011, 02:21:28 PM
I would be interested in knowing what the exact MOA on a 16'' midlength AR is. It seems to somewhere around 1/2 per click,, but knowing the exact clicks would make me feel better!

Roland

The sight radius on my mid-length in 16 3/4" if you want to figure out the MOA.