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Thread: Need to know about an AR-10

  1. #21
    Member Hummer70's Avatar
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    Mar 2016
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    Barrel length can be critical for several reasons.

    1. The shorter your barrel the slower the velocity you get from your ammo. On center fire rifles depending on caliber etc you can lose 50 feet per second for every inch you cut off.

    2. There shorter the barrel the higher the decibel level. Even the 20" barrels AR10s are offensive to shoot next to. I would not go shorter than 20 on any AR and shoot nothing without ear protection. When I shot competition I used foam ear plugs and with muffs over them.

    3. If you are shooting iron sights the short barrels require sights to be closer together and young shooter's eyes can accommodate the close sight spacing but you see very few outstanding shots above age 35 with service rifle sights.

    4. Scopes obviously can help here but finding a scope with internal adjustments that are repeatable is very rare regardless of what you pay for the scope.

    5. You will likely find that factory ammo is IFFY insofar as grouping is concerned as it is loaded for one reason, you buy it.

    6. I don't know any top flight long range shooter that does not load his own.

    7. Commercial cases are also not designed in a way to give long case life. Some commercial big names can only be reloaded twice, others 5-7 times. Military match cases can be reloaded a min of 75 times.

    8. What takes out commercial cases is the case heads are soft and the primer pocket gets bigger quickly. Soon as the primer pocket enlarges you will get gas leaks around the primer and it will start eating away your bolt face.

    This is just a few of the things you need to consider when fielding a rifle you plan to use for years.

    9. If you care for a good rifle you can get 10,000 rounds on a barrel and still be shooting well.

    10. When you shorten a barrel you have to decrease the size of the gas port or you will overdrive your weapon. CIP when the Short ARs came out they forgot to reduce the size of the gas port and the high pressures opened so quickly that the extractors were deforming the case rims to the point the cases could not be reloaded.

    The same problem raised up with Tanker Model Garands. I had one that was overdriving pressure and I had to make a gas plug with a vent hole in it so the op rod would not be wrecked. I made the new gas plug out of stainless steel and kept enlarging the hole until the case ejection was right on the money and cases went between 1:00 and 2:00 regardless of bullet weight.
    Last edited by Hummer70; 01-01-2022 at 03:05 PM.
    NRA Life Member since 1972. Distinguished High Power Rifle, Distinguished Smallbore Prone US Palma Teams & US Dewar Teams,(2) US Palma Trophy Individual Match wins, Centenary Trophy, Certified Small Arms and Ammunition Test Director, Aberdeen Proving Ground, Maryland. Conducted testing for US Army Test and Evaluation Command, Army Material Systems Analysis Activity and US Marine Corps. Army Sniper Rifle consultant. Test& evaluation of Small Arms, at the Federal Law Enforcement Training Center.


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