reddot Posted January 8, 2003 Share Posted January 8, 2003 I have an older AR-15 purchased in late 80's. I used it for NRA hi-power several seasons and then pretty much parked it untill the 3 gun bug hits me about a year ago. I started practicing a bit more and I put maybe 1k-2k rounds through it and suddenly it starts failing to feed rounds. It has been thoroughly cleaned and I can't see anything blocking the gas tube or anything. At first I just figured it was an ammo problem, but I tried about 20 different loads in 6 mags including some of my old hi-power stuff that always runs, I can't get anything to run reliably, sometimes it doesn't eject the spent case but usually it just doesn't pick up a new round. The extractor does seem to be grabbing the brass, it just doesn't get all the way out. Is there something I don't know about that wears out on these or what? Anybody have this experience? I am currently shooting a variety of Hornady and Sierra bullets on top of VV N-135, N-140 and AA XMR-2015. Any input appreciated, I am stumped! Link to comment Share on other sites More sharing options...
Patrick Sweeney Posted January 8, 2003 Share Posted January 8, 2003 Questions; Original Colt, or built from parts? If Colt, move on. If built, check the headspace. If the headspace is correct (if built for High Power it might be too tight) then your extractor spring may have died. Replace it, and the little synthetic stud inside it. You might also add a D-Fender to give it more boost. While you're at it, take the buffer and spring out and scrub the tube clean. Debris can get in and slow things up. Not usually a problem by itself, but in conjunction with other marginal items can be enough to tip it into unreliable behaviour. Link to comment Share on other sites More sharing options...
TBF Posted January 8, 2003 Share Posted January 8, 2003 You might also check the condition of your gas rings, if you hold bolt carrier upside down with bolt key etc. removed, bolt should not fall out by itself (do this without lube).If ok. Clean buffer tube,lube , reassemble , go to range.Fire a few rounds to blow lube out of rings, Load one round in mag, Fire and see if bolt locks back, if it does not you may have carbon buildup in gas tube or front sight assy.Also check carrier key (the thing on top of bolt the gas tube goes in) for tightness. Travis F. Link to comment Share on other sites More sharing options...
DogmaDog Posted January 8, 2003 Share Posted January 8, 2003 I've seen failures to feed happen in M-16s because the bullets weren't pushed all the way back in the magazine. Before tearing apart your gun, try just whacking the back of the mag against your palm to knock the rounds all the way back. Good luck, DD Link to comment Share on other sites More sharing options...
kurtm Posted January 8, 2003 Share Posted January 8, 2003 Reddot: There is some good advice here. I would just scrap the gas rings and go from there. I have seen rings that were worn and cracked pass the bolt upside down test! Just replace them! they are cheap. Next, the end of the gas tube may be worn out, they are supposed to have sort of a little ball on the end that goes into the carrier. Next, check and make sure nothing has gotten into the carrier key, that little periscope looking thing ontop of the carrier. Check by running a pipe cleaner through it untill you see it protrude into the inside of the carrier. Clean the chamber really well. If it worked befor I wouldn't think it was the chamber dimentions them self but if it keeps doing it after all the gas system is gone through have it checked. KURT Link to comment Share on other sites More sharing options...
TBF Posted January 8, 2003 Share Posted January 8, 2003 Forgot to mention gas tube, look at the top for wear, you dont have to tear apart your whole gun. Break one of your wifes/girlfriends compact mirrors and use a small piece to look as best you can. TBF Link to comment Share on other sites More sharing options...
Mickster Posted January 8, 2003 Share Posted January 8, 2003 I second the motion to replace the gas tube. While you're at it, replace the key with a new one also. My AR was making me crazy with sporadic failures to feed until I replaced the above mentioned parts. Runs like new now. Link to comment Share on other sites More sharing options...
TBF Posted January 8, 2003 Share Posted January 8, 2003 I would look at gas tube before replacing, if its rear (bolt) end isnt damaged, and spray solvent ( gun scrubber, brake parts cleaner, etc. ) sprays through it alright with the little red extention tube that comes with the can,(compressed air is handy for this too) then it is not likely clogged. not that its really that hard to replace, but if it is OK why mess with it? (this is called "condition based maintainence " in corporate speak. But seriously, if you do not have a friction problem ( crap buildup in buffer tube or upper ), fire it and look for soot marks at carrier key(where it mounts to bolt carrier), front sight gas leakage (small amount usually not a problem). And , after firing a few (20+) rounds to blow lube out of gas rings, see if it locks back the slide after loading a single round at a time in mag, if it does not, you have short recoil. and a gas problem (if its not leaking then gas tube is likely fouled ). Be sure to replace gas rings if bad/questionable, or just replace anyway. Travis F. Link to comment Share on other sites More sharing options...
reddot Posted January 9, 2003 Author Share Posted January 9, 2003 Thanks to all for the suggestions, it is an original, box stock Colt. I have blown air through the gas tube and and I can feel some air coming through. I also cleaned and lubed the buffer and tube thoroughly.I will get some new rings and a tube ordered . Is the carrier key really that prone to failure? I will get one of those also. Is Quality Parts and Brownell's still the best place for parts ? DD, I do always whack the back of the mags, thanks though! Link to comment Share on other sites More sharing options...
Les Snyder Posted January 9, 2003 Share Posted January 9, 2003 Reddot... if you haven't ordered the gas ring yet, would suggest one of the continuous one piece rings like the McFarland ring. My Colt rings were worn almost in two at about 5000 rounds. regards... Link to comment Share on other sites More sharing options...
SGDM Posted January 10, 2003 Share Posted January 10, 2003 Reccommend a Mcfarland gas ring and make sure the key is tight. Check the OAL of your bullets too. If you shoot the heavy ones, sometimes the nose will hang in the Mag. Most of the malfs contributed to the AR are mags. Make sure your mags have good springs/followers. A good place for parts is Georgia Precision. Good Luck Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now