Posted: 7/9/2012 1:16:02 PM EDT
| A couple of weeks ago I had the opportunity to take a Competition Carbine class taught by Trip McIngvale. First let me say it was a great class. Lots of good information and lots of rounds down range. I brought my16" OBR Light and a DPMS I had tricked out. The first couple of engagements my OBR had jamming issues. I had plenty lubrication on the OBR and was using Magpul PMAGs. I tried different magazines and the OBR would try to run. I notice the PST was not fully in the unsuppressed position so I corrected that operator error. Still the OBR would not run. Trip loaned me one of his magazines loaded with Hornady 75 grain steel cased bullets. The OBR ran flawlessly. I went back to my mags and ammunition and the jamming issues returned. Reluctantly I returned my OBR to the rifle case and completed the class with my DPMS. Late in the afternoon one of the other students ran out of ammo before the end of the engagement, so I pitched him a loaded mag so he could finish. He was shooting a 16" OBR Light (like mine). Amazingly he began having jamming problems. So now we all knew this was definitely ammo related. I had brought only one type of ammo, Sieller and Bellott 55 grain. I have used Seiller and Bellott ammunition in my handguns for years and never had any issues that could be directly linked to the ammunition. My question is what is the bullet weight that make OBRs run best? |
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I was under the impression that bullet weight only mattered as far as rifle twist was concerned, while in the barrel. After exiting things like effective distance etc come into play.
You should chrono the S&B and see what velocity you are getting out of it? Could be a bad batch that is underpowered and not cycling the bolt as it should... I mostly only shoot various 55gr ammo with no prob, switching to 77gr when going for long range accuracy. |
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Bullet weight has absolutely no bearing on feeding issues
Obviously, it was your ammo What ammo were you shooting? Hand loads are iffy unless you are a very experienced reloader in a semi auto black rifle Russian and Easter Urooen ammo is purely cra and most have corrosive primers. Nd varnished stel cases..the varnish or lacquer Will wind p in our chamber and restrict the forcing cone eventually It never pays to use cheap ammo in any gun,particularly an AR Use the best ammo I can afford,but stay away from Ussian 'Bear' ammo of any kin Shoot ammo with only brass cases in an AR and non corrosive primers Best reliable affordable .223 in my opinion is Federal American Eagle 55 gr...totally reliable nd affordable The best in my opinion is Federal Lake City 55 gr and comes on stripper clips..use a Lula strip loader loading your mags is effortless from strippers. Yep, it was your cartridges for sure I prefer metal mags over P Mags,but that's just me I mostly use Colt branded mags even though Colt contracts out for them...older Colt mags with black followers are in my opinion the best |
| The ammo was factory Sieller and Bellott, brass cased, non-corrosive, boxer primed. The issue was cycling, it appeared to be short stroking. The bolt carrier not coming back far enough to eject the spent cartridge. I have the original factory spring and buffer in the OBR. I thought the bullet weight would have a direct relation to the recoil and the reloading cycle. Could it be the ammo has too light of a powder charge (not a hot enough round)? I have some Hornady 55 grain steel match ordered and also some 75 grain Hornady. |
| As they said above it has nothing to do with the bullet weight, My guess would be that either the cases themselves or the OAL (over all length) of the round is too long causeing your cycling/jamming issues. I doubt its undercharged but thats also a possibility, like they said if you want to sick with that ammo see how fast its flying via chrono, or shoot it back to back with an american eagle .223 and see how much of a pressure differrnce there is at the chamber. Either way do yourself a favor and dont run any cheaper ammo than american eagle/M855 & learn to reload in the meantime. |
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You are absolutely right, it is underpowered. You're shooting junk ammo, and they cut corners anywhere they can, including powder load. Go buy some decent ammo (M855 equivalent, for example), and I'm betting your problems go away. Not having problems with their pistol ammo in one or few guns is not a good indicator of the performance in a rifle.
Usually, the higher bullet weights will be loaded "hotter" to accomodate the physics of a heavier bullet, but your problems don't stem from the actual bullet weight. |