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4/22/2019 5:32:20 PM
Posted: 11/21/2014 5:06:23 PM EDT
[Last Edit: 11/21/2014 6:40:14 PM EDT by ENG4INE]
I recently registered my Bushmaster XM-15 16'' as an SBR. I received my tax stamp and installed a 10.5'' black hole weaponry 5.56 barrel, spikes tactical T3 buffer and an a AAC comp. I installed the extra heavy buffer because I plan on shooting it with my can sometimes when that tax stamp comes back. Today I took it out for the first time and put about 50 rounds through the rifle. When I went to clean the rifle I found that one of the gas rings had blown and the firing pin retaining pin had bent. (See pictures) Im trying to figure out if I should just buy new gas rings and a retaining pin and go on with it or if something other than previous wear could be the reason for the failure. Ammo used was the 100 round bulk pack Federal 55grain .223 FMJ from walmart. Thanks for any help.

Link Posted: 11/21/2014 5:20:36 PM EDT
The pin doesn't look very bent. I would just replace the rings and keep shooting.
Link Posted: 11/21/2014 7:29:31 PM EDT
[Last Edit: 11/21/2014 7:34:09 PM EDT by Rick_Lind]
I would just clean it up, replace the rings and pin, and keep going. From the looks of the bolt it has been shot a lot and has a lot of carbon build up. Scrape off the carbon from the bolt and carrier and make sure there are no burrs and that it's well lubed next range session.
If it's cycling OK your spring and buffer are probably about right.
You should have a better idea the next time you clean it if you actually have a problem.
Link Posted: 11/21/2014 10:26:58 PM EDT
that pin looks like just about every one I own. You're fine. Agree on the advice to put new rings on it.
Link Posted: 11/21/2014 11:19:05 PM EDT
McFarland Gas ring is your answer.
Link Posted: 11/22/2014 2:08:49 AM EDT
Link Posted: 11/22/2014 1:38:51 PM EDT
The FP retaining pin should never be bent. This usually occurs when a notched hammer is used with an unshielded (old semi-auto type) bolt carrier. In some applications the hammer notch can catch the firing pin and force it up, bending the pin. Bending the pin introduces metal fatigue which may cause it to break and release the firing pin, which in turn releases the bolt cam pin. This will usually have dramatic results if firing continues. Bottom line, a bent pin is a warning. Guns usually tell us things before bad things happen - its wise to listen to them. Figure out what bent the pin and relieve the situation.
Link Posted: 11/22/2014 1:46:29 PM EDT
With how inexpensive things are right now, I would have just kept the old BCG with the old barrel and bought a complete BCG for the new barrel.

Or, at least a new bolt for the new barrel and used the old carrier. (New Barrel, New Bolt)

If you have the money for the tax stamps, you have the money to for a $99 BCG.
Link Posted: 11/23/2014 12:56:15 AM EDT
Link Posted: 11/27/2014 2:13:16 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By SandWMandP15Tee:
McFarland Gas ring is your answer.
View Quote

This is the route i went after destroying the gas rings on my 7.5" upper.
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