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Posted: 9/3/2005 12:35:49 PM EDT
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I just bought the following Bushmaster M-4 http://www.bushmaster.com/shopping/weapons/bcwa3f16m4.asp 16" barrel, etc. I completely broke down the gun, cleaned and lubed it, before going to the range. It consistently fails to eject when shooting 55 grain 5.56 ammo, after the first round is shot. I have tried Blackhills ammo and another brand, and it makes no difference. Tried two different magazines, again, no difference. It did this five times in a row. It reliably fires .223 ammo, 62 grain. I tried two different brands (Remington was one). It emptied two magazines with zero problems. Has anyone else experienced this problem? What could be the problem? Thanks... |
Hey jkstexas...I and a few others have had the very same FTEX malfunctions with the 55gr Blackhills and Bushmaster M4 Types...namely 16" Patrolmans Carbines...but you say that the 62grs run fine?....cool...as that kinda confirms some of my suspicions...now...chexk it out...do me a favor and remove your BCG (Bolt Carrier Group)....then (by hand) move your bolt for and aft slowly several times...does it feel kinda "Sticky & Skittery"???....like the internals of your bolt carrier aren't smooth?...creating a considerable amout of lock/unlock resistance?...cause that's what mine used to do until I polished it out a bit and now it's far smoother but I haven't gotten around to test firing it and I suspect the reason you had favorable results with the 62gr'ers was due to the increased chamber pressure of the 62's being able to overcome the stickyness of the rough BCG...where the 55gr Blackhills is just too soft of a load to get the sticky, rough bc internals to funtion/break-in properly. Please let me know what you find and T.I.A. Bill.  PS...here's some pics of what I experienced... Here's some metallic burrs that popped out of my BC after running a .45cal bronze brush through it....  After a few more brush strokes I then broke out my polishing equipment..  and blinged out the internals of my bolt carrier...  The bolt slides for and aft much smoother now and the blow test on the gas seals even made what used to be just a slight leak completely go away...can't wait to test it...and I'll be taking some other ammo with me as well...but once broke-in and running it should operate just fine with the BH 55gr regardless of the soft load....as tere was no call for the BC internals to be that rough and sticky.  L8R, Bill.
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| You need a #60 O-ring. I just find it a little weird that a lot of people are having these issues with patrolmans. Mine runs flawlessly with XM193, BH 55gr, WWB, Rem UMC, GA. Hell everything I've put through it. Probably about 2000rds. My buddy that had issues was running an 11.5". |
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When I had that problem with my new Bushy, I was my putting too much oil on the bolt-face and little brass shavings in the extractor pin channel. I had to disassemble the bolt clean out the shavings, learn how to oil the rifle properly, and run enough rounds through to break it in. Steve ETA :spelling |
Thanks for the advice. |
I will check it out shortly. |
Thank you so much fror checking and posting sir...can't tell ya how much I appreciate it and I'm now officailly calling...."BINGO!!!"  I say it's the resultant combination of three things... 1. The inherent yet slight tuning sensitivity of the carbine short gas system coupled with... 2. The "softer loadings/lower chamber pressures" of 55gr. Blackhills Blue Box ammo and ultimately?...and the straw that broke the bushmasters back?... 3. Rough BC internals imparting increased amounts of "Statis Hystersis" (read: frictional resistance) in the BCG. stir gently and viola...FTEX...and/or...Weak Ejection...gas pulse got ate up trying to unlock the sticky, resistant BCG. and this is not to say that one might not be better served with a stronger XP extractor spring or by adding an O-ring or shooting higher chamber pressured 62gr ammo as....you would...but it is nothing more than an "affective band-aid" and not the resolving or addressing the primary root cause...which is now officially in my humble and most modest opinion highly attributable to.... "Rough/Sticky Internals Inside The BCG." Can I get an amen? LOL!!! Thanks again jkstexas and...L8R, Bill.
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And Stickman is correct..."I DO NOT OIL MY BOLT FACE".....unless of course Mrs. FUZ1ON is feeling a little extra wild & frisky that evening...and even that hasn't happened in years!!! LOL!!! L8R, Bill.
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| So, is it worth it to send it back, or stick with the more expensive 62 grain 223 ammo? The 55 grain Black Hills and 55 grain Federal both fail to eject. Will an o-ring make it able to fire 55 grain ammo reliably in your opinion? I don't have the polishing tools that you have to do a polish job. |
jkstexas...I don't think BM would fess up to rough internals and more than likely they'll claim it a product of the break-in period where they expect that within 200rds run-in the components will "Wear Into Each Other" as you go through break-in...but I wouldn;'t send my carbine back over that...I'd just head to the range with a bottle of clp and 200rds of High Pressure 62gr and have at it...and I'd bet a 6pack that after the final cleaning...after 200rds of 62gr...your Carbine will be broke-in with your BCG smoothed out and ready to gobble up 55grs all day long...and yeah...justa rid yerself of the FTEX pita a #60 O-ring wouldn't be a bad investment...24 cents at home depot...might even get away with blazing the 55gr with that....but I wouldn't be in any rush to RMA it back to BM as...if you don't have "LEO Priority" it could be weeks before ya get it back...which kinda sux...especially these days. I'm no BM armorer but I am a 20+ year Tool& Die Machinist and..since you helped me out here?...if ya wanna send me your BCG and enough cash to ship it back to ya I'd be happy to polish yours out for free...up to you and no offense either way...but I'd be happy to help ya out if your so inclined. Thanks again and L8R, Bill.
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I have to ask.... I've never seen the inside of an AR... Is this O-ring something that isn't on the gun from the factory? Do the O-rings wear out quickly? I'm interested since I just ordered a Bushy M4 and I'm sitting on a 1000 rds of Wolf ammo (500 rds of 55gr and 500 rds of 62gr) |
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