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Thread: Better than Mil-Spec?

  1. #71
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    Actually, I mis-spoke.

    The acceptance criteria for an M4A1 is a ten shot group with an extreme spread of 5.6 MOA. The misalignment of the sights from mechanical zero to intended POA is 5.2 MOA. The test ammunition must have a SD of between 3.4 and 4 inched at 600 yards.

    The acceptance criteria for an M1 Garand was five shots within or cut a 5 inch circle at 100 yards, making the limit an extreme spread of about 5.3 MOA, with "ammunition of known good quality".

    The poor initial accuracy of production M14s was the subject of much writing in the early 1960s. This resulted in a rather complicated accuracy acceptance procedure that took into account the average displayed accuracy of the test ammunition. But, this all was added to the specifications around 1965, after production ended.
    Last edited by lysander; 02-24-20 at 22:27.

  2. #72
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    Quote Originally Posted by lysander View Post
    The acceptance criteria for an M4A1 is a ten shot group with an extreme spread of 5.6 MOA.
    ^ Is this with the hot or cold barrel? What kind of ammo? Mechanical rest or not?

    Quote Originally Posted by lysander View Post
    The misalignment of the sights from mechanical zero to intended POA is 5.2 MOA.
    ^ What does it mean? How is it calculated? Is this under certain conditions?


    Quote Originally Posted by lysander View Post
    The test ammunition must have a SD of between 3.4 and 4 inched at 600 yards.
    ^ What does that mean? How is this calculated (certain string of fire)? What ammo? Mechanical rest or not? Hot/cold barrel?


    Final question - are those numbers and tests only meaningful during the initial trials/acceptance testing or the actual production rifles/batches go through the similar tests to confirm that they meet the specs?


    Thanks for the interesting info.

  3. #73
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    Quote Originally Posted by Humpy70 View Post
    There was a study conducted at the Army Marksmanship Unit in the 60s to evaluate the AK-47 and it was found that the best shots in the Army could just hit a E silhouette at 300 Meters.

    A guy I worked with who was at Rock Island before Rodman Lab was moved to Picatinny where I got to be good friends with him. He passed last year. At any rate he told me he was on a acceptance evaluation and the M14s were given a waiver and were shooting like 6.5". Acceptance was 5.5".

    As a rack grade rifle it was not that good but in a accurized configuration it became outstanding and could be made to shoot under a inch at 100 when bedded correctly and rebarreled with a non chrome lined barrel.

    The best thing about them was tagging the opposition with a solid shot in thoracic cavity from close to long range did the job with one round which is the same conclusion the Army Wound Ballistic's Lab came to.
    Maybe the rifles they used were darn near shot out? Both of my AK's are pretty exceptional. The East German is 2 to 3 moa and the Vepr is better than 2. With a scope and RS regulate mount I've seen open hand sized groups from it at 400 meters using lacquered steel cased mil spec stuff.

    Sent from my SM-G970U using Tapatalk
    Last edited by MikhailBarracuda91; 02-25-20 at 00:38.

  4. #74
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    Wow somebody screwed up big time to make 7.62X39 that shoots that well. I had a buddy with one and he brought it down and best we could do was about 9" at 100 yards from the bench. I was able to get it about 7" best I can remember.

    I also remember being told one of the famous Russian women snipers visited Benning and they let her shoot a match rifle and surprisingly she was not that good of a shot. I forget her name but I remember I had heard it before years ago.

    Lysander, see if you can find early acceptance specs for the short barrel rifles. I remember asking figuring they were going to be relaxed and was told it was still 4.5" and then about I think it was 90s they had relaxed the dispersion requirements for the M855Ammo so they could get more accepted since we were on 386 status.

  5. #75
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    Quote Originally Posted by Humpy70 View Post
    Wow somebody screwed up big time to make 7.62X39 that shoots that well. I had a buddy with one and he brought it down and best we could do was about 9" at 100 yards from the bench. I was able to get it about 7" best I can remember.

    I also remember being told one of the famous Russian women snipers visited Benning and they let her shoot a match rifle and surprisingly she was not that good of a shot. I forget her name but I remember I had heard it before years ago.

    Lysander, see if you can find early acceptance specs for the short barrel rifles. I remember asking figuring they were going to be relaxed and was told it was still 4.5" and then about I think it was 90s they had relaxed the dispersion requirements for the M855Ammo so they could get more accepted since we were on 386 status.
    I do a good bit of AK bashing here, but if I drop the hyperbole that I use to paint the M4 as a vastly superior weapon, I must admit that the AK, even in 7.62x39 is a perfectly serviceable weapon. There’s a saying: the M4 is more reliable than you might think, and the AK is more accurate than you might think. Most are capable of accuracy that an army would find acceptable.
    RLTW

    Former Action Guy
    Disclosure: I am affiliated PRN with a tactical training center, but I speak only for myself. I have no idea what we sell, other than CLP and training. I receive no income from sale of hard goods.

  6. #76
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    It's pretty much a matter of fact that the ak and ar systems are the most efficient and proven frontline military rifles today. Just like the M4/M16 Russia definitely knows how to make a quality AK.

    I have both, and I'm not sure which I prefer TBH. The manual of arms is totally different, but man is it great to not have blinders on and think the AK is commie trash. That is pure idiocy.

    The AK is designed for steel cases ammo, and I've shot thousands of rounds with the same reliability as my AR's. The big difference is the price in ammunition, the accuracy is not a big difference if you buy a real deal AK.

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  7. #77
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    Quote Originally Posted by alx01 View Post
    ^ Is this with the hot or cold barrel? What kind of ammo? Mechanical rest or not?
    In accordance with MIL-DTL-71186, Detail Specification - Carbine, 5.56 millimeter - M4A1, paragraph 4.5.4. It's a long paragraph, so I'll let you read it, but basically:
    - fifteen rounds are shot for semi-auto functional testing, the middle ten of these are shot for accuracy

    - Cartridge, 5.56mm, M855, made in accordance with Drawing 9342868 (although now I suspect it would be M855A1 IAW DWG 13020533)

    - ". . . shall be held in a firing stand simulating shoulder firing per [DWG] 11837946 (semi-automatic/targeting and accuracy firing) . . ."

    Quote Originally Posted by alx01 View Post
    ^ What does it mean? How is it calculated? Is this under certain conditions?
    It means exactly what it sounds like it means. You mechanically zero the rifle per TM 9-1005-319-10 and FM 3-22.9, aim at the aim point of the target and shoot. The center of the group needs to be within 5.2 inches of the aim point.

    Quote Originally Posted by alx01 View Post
    ^ What does that mean? How is this calculated (certain string of fire)? What ammo? Mechanical rest or not? Hot/cold barrel?
    Ammunition comes from the factory with a big list of qualities that were tested and recorded for that lot, the Standard Deviation is one of those listed particulars. What information is requires and how they arrive at it is all covered in DTL-13038145, M-SCATP. We've covered what ammo and the rest....

    If you are asking what is a standard deviation is, study up on statistics.

    Quote Originally Posted by alx01 View Post
    Final question - are those numbers and tests only meaningful during the initial trials/acceptance testing or the actual production rifles/batches go through the similar tests to confirm that they meet the specs?


    Thanks for the interesting info.
    There are two classifications of tests, First Article and Conformance.

    First Article Tests are exactly what it sounds like. When a new supplier, or a supplier with a break of a certain length of time between deliveries, delivers the first production lot, a certain number of samples must be subjected to a First Article Test. First Article Tests can also be written into the contract to occur at set intervals, either calendar, or production, or both.

    Conformance Inspection, is required on all weapons, among the long list of Conformance Inspections, function firing, targeting and accuracy are included, so every single M4A1 delivered to the US Government under military contract, has had at least 45 rounds through it (15 for the semi-auto functioning and 30 for the full-auto/burst functioning tests).

    If you are interested in stuff like lots size, sample size, what happens with rejections, etc, hunt down a copy of MIL-DTL-71186, MIL-DTL-70599, MIL-DTL-63997 or MIL-R-63997, the requirements are pretty much the same.
    Last edited by lysander; 02-25-20 at 17:32.

  8. #78
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    Does anyone know what happens to the rifles that don't hit within 5.2 inches of the aiming point with the sights set to mechanical zero?

  9. #79
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    Quote Originally Posted by Humpy70 View Post
    Wow somebody screwed up big time to make 7.62X39 that shoots that well. I had a buddy with one and he brought it down and best we could do was about 9" at 100 yards from the bench. I was able to get it about 7" best I can remember.

    I also remember being told one of the famous Russian women snipers visited Benning and they let her shoot a match rifle and surprisingly she was not that good of a shot. I forget her name but I remember I had heard it before years ago.

    Lysander, see if you can find early acceptance specs for the short barrel rifles. I remember asking figuring they were going to be relaxed and was told it was still 4.5" and then about I think it was 90s they had relaxed the dispersion requirements for the M855Ammo so they could get more accepted since we were on 386 status.
    You are correct. The initial specification (1987) for the XM4 was 4.5 inches, extreme spread at 100 yards. By 1994, the requirement was relaxed to 5.0 inches, and by 2009 it was further relaxed to the current 5.6 inches.

    However, there were other changes made. Initially the semi-auto function test and the accuracy tests were separate, so up to three warming rounds were allowed to condition the barrel. Someone obviously calculated the $$ saving of running the function test and accuracy test concurrently and thus saving 13 rounds for each carbine tested.

    The minimum accuracy requirement of the test M855 ammunition has been an SD of 3.4 to 4.0 at 600 yards since day one.

    Interestingly enough, the XM4 seems to have been required to be more accurate than the M16A2. In 1986, the requirement for the M16A2 was 4.8 inches extreme spread at 100 yards. But then an 'apples-to-apples' comparison is difficult as the ammunition requirements was different. The ammunition was required to have a mean radius of 1.2 to 1.4 inches at 200 yards, how that relates to a SD of 3.4 to 4.0 at 600 yards is for a statistician to figure out.

  10. #80
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    Quote Originally Posted by Humpy70 View Post
    Does anyone know what happens to the rifles that don't hit within 5.2 inches of the aiming point with the sights set to mechanical zero?
    The manufacture gets to mess with them until they do. (EDIT: but they cannot alter the parts away from drawing tolerances.)

    However, if they have too many of them that have to fixed, for any failing, they get a bad report card for the lot, and it goes in their permanent record and used against them during contract time.
    Last edited by lysander; 02-25-20 at 17:37.

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