Jump to content
Rimfire World Community
Visit Brownells Visit AR15 Builder Visit Visit Site Visit Ballistic Advantage Visit Aero Precision Visit Cabelas

my M4 has gone belly up


rodent.22

Recommended Posts

My C/U M4 has developed a non-ejecting malfunction. The ejector looks perfect, rifle is clean. I seem to have a doorstop on my hands. Any suggestions fellas? It might fire 10 rounds, then a failure to eject. Maybe 1 round. No rhyme or reason. I've tried several brands of ammo- no change. I've tried several magazines also.

Link to comment
Share on other sites

Im not familiar with the rifle but whenever I have had a .22 semi auto that did this it meant there was buildup preventing the extractor from grabbing the case. On one rifle the carbon looked like it belonged. Wasnt till I poked it with a dental tool that I saw it wasnt right.

Link to comment
Share on other sites

TM I just busted it down and the buffer is broken and the buffer pin is bent. The bolt is clean, the extractor and spring are totally clean and free. The extractor is sharp and the bolt face indentations are clean. The chamber is not dinged, the cases just fall out of the chamber. Maybe high velocity ammo is damaging this thing.....

Link to comment
Share on other sites

Thanks. We had one other colt owner with a broken bumper.... If I remember correctly, (don't bet on it), he was using HV ammo with his recoil spring adjusted for std velocity ammo, so the spring wasn't soaking up all of the recoil, and the slide(bolt) would hit the bumper every shot. When these Colts first came out, there were several different methods out there for setting the recoil spring. I saw a utube video that specified 9 turns in, and set mine that way. Ended up ruining the spring. In an email from customer service they said flush for std, in 4 turns for HV. But, in your case, at least the inexpensive part broke.

Link to comment
Share on other sites

dammit, the bolt and ejector is SPOTLESS, the ejector is sharp, and it's ejecting nothing. Every fired shell is either not pulled out, or it's pulled out into the top of the magazine, being crushed by the bolt coming back forward. The ejector spring feels good, the ejector snaps back every time.

Link to comment
Share on other sites

dammit, the bolt and ejector is SPOTLESS, the ejector is sharp, and it's ejecting nothing. Every fired shell is either not pulled out, or it's pulled out into the top of the magazine, being crushed by the bolt coming back forward. The ejector spring feels good, the ejector snaps back every time.

Please excuse me if this sounds noobish because I'm not very familiar with the Colt/Umarex. But I had the same type of issue with my M&P15-22. You said the ejector is sharp. Did you mean the extractor is sharp? The reason I ask is because I had my extractor come out on my 15-22 so when cycling it would sometimes not extract the casing from the chamber then try and jam another round when the bolt came forward. When the casing did come out of the chamber it would just turn sideways in the ejection port then get crushed by the bolt. I didn't notice the extractor was even missing until I took it back to the range the next time and tried firing a few rounds and was doing the same thing so I took it home and disassembled for a good cleaning and noticed the extractor gone (which S&W replaced promptly).

As I said, I'm not at all familiar with the Colt but if it is at all similar to the design of the S&W, perhaps there is some buildup between the bolt and the extractor preventing the extractor from pivoting inward toward the center of the bolt face, which would prevent the extractor from grabbing the rim of the casing.

  OK I googled an exploded view of the M4 and see that it is remotely similar to the 15-22. I would definitely look carefully at the channel that holds the extractor. The extractor looks to be held in by a roll pin which should be easy enough to remove, just be careful of the spring and spring insert not flying out.

Anyway I hope this helps and I havn't just stated the obvious and/or redundant.

Good luck.

Link to comment
Share on other sites

dammit, the bolt and ejector is SPOTLESS, the ejector is sharp, and it's ejecting nothing. Every fired shell is either not pulled out, or it's pulled out into the top of the magazine, being crushed by the bolt coming back forward. The ejector spring feels good, the ejector snaps back every time.

Weird problem, I will try to get a close-up pic of mine & post, maybe you can spot a difference between yours & mine. BulletCushion posted some good info too, check that extractor groove!

Link to comment
Share on other sites

Hey Rodent,  took mine all apart, here is a picture of the bolt, or slide. Make sure your extractor is in the correct position, it should easily move outward in order to pass over the cartridge rim, and the hook should be sharp. If the hook is not sharp it will not pull the brass out of the chamber. It is spring loaded, so make sure your spring is functional and intact. The ejector is one non-moving part, sits on the two pins, insure it is not bent. Other than that, hard to say with out some pics. I have disassembled my bolt or slide several times, and it was full of sludgy gunk that given time will fossilize into a granite-like material....

Good Luck!

TM

post-10-144124389815_thumb.jpg

Link to comment
Share on other sites

I can't say I fully understand all aspects of the "blowback" system of the semi-auto rimfire, but this is my understanding (correct me if I'm wrong): 1. the EXTRACTOR'S main function is to pull out a round or shell manually, AND to hold the shell in place so the EJECTOR can kick it out. 2. the EJECTOR is a stationary part that is struck by the base of shell as the bolt is "blown back", and is what flips the shell outward. I really don't think the extractor has that much to do with the "ejection" process when firing. The blowback effect should un-chamber the shell either way. Right? Can you insert a round into the "recess" on the face of the the bolt, and the extractor will latch on to it? Can you MANUALLY extract/eject a round? If a round can be manually ejected, I would seriously look at the EJECTOR. It must be held firmly in place, and can't be boogered-up on the end, and definitely not BENT.

Link to comment
Share on other sites

One other thing, is it possible after replacing the buffer and pin, that you may have adjusted the bolt-spring tension inward TOO FAR? I found this out when I started shooting a lot of sub-sonic ammo, and forgot to adjust the spring all the way back. The shells would "stovepipe" every time! Just enough "recoil" to get the shell out of the chamber, but not enough for the bolt to go back far enough, or fast enough for the ejector to send it out the door. You might want to remove the adjusting screw and spring all together, and be sure the bolt moves all the way back (and forth) freely, and there's nothing hung-up in there binding it up (like the ejector). Also, check to make sure the PIN holding the top and bottom halves of the bolt together hasn't backed-out and is contacting the receiver housing. Mine did that once too.

Link to comment
Share on other sites

  • 4 weeks later...
  • 1 month later...

sorry guys, I've dropped off the face of the earth. We've sold our home of 20 years and bought a retirement home out in western Virginia. We've been packing and moving till we're about to drop. Anyway TM, I PM'd you before about losing the ejector. This was in a large den with brand-new carpet. I went over it 5 times with a fine toothed comb. I ran the Oreck over it at least 10 times since I realized it was missing, listening for a clink every time. Nothing. Well, what the hell- it must have flew out when I was shooting and I didn't realize it. Well I was emptying the den Thursday and there was the damned thing laying in the middle of the den carpet, pretty as you please..... It's a bitch getting old. Maybe just maybe I'll get it together in a couple of weeks and see if the damned gun will still shoot. Thanks for the good advice from you all....Gary

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...