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Posted: 5/13/2011 9:00:37 PM EDT
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I have a S&W M&P AR15x 5.56 NATO....
When I run any 5.56 rounds it cycles fine...but when I run steel cased .223 pmc uncoated, not everytime, but too many times the case jams and don't eject. Then I'm forced to use a range rod to drive it out, by looks of casing it's fire forming as it's ejecting and stopping in chamber. I do know .223 is a tad bit smaller and a less charged round.... ??????? IDEAS ??????? 
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Quoted:
First of all.. is your AR lubed up well? Also, do not run brass then switch to steel case and back to brass and steel case. It can cause stuck cases due to the carbon blow back. Your rifle may just not like that particular ammo. Yes clean between mags and wipe down and oil all internal parts. Fired coated steel this am and no problems at all! But think I'm gonna stick with all brass to work up my own loads! Thank you sir! |
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You answered your own question with your last statement, IMHO.
NATO (5.56) loads run at least 3100 to 3200 fps out of a 20" muzzle. I've seen Russian ammo reported as low as 2700 fps by some members. Sometimes if your gun is new, dry, or has a plated bolt carrier, it's too tight and it will need all the juice it can get from the round to cycle. My DPMS Classic 20 had short cycling problems, even after I sent it back to DPMS. I substituted the come-with plated bolt carrier with a stock unit from Delton, lubed it up, and short cycling problems stopped. |
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