I have a new fixed mag AR built by a local guy. I only shot it once before (only 10 rounds) and it seemed okay except the bolt didn't lock back on the last round. I figured it was simply break in period. I'm new to ARs, and it's my first rifle.

I was able to get some Wolf steel case 223 from Target Sports and took it out tonight. It would not fire more than one round without a malfunction. In one instance I found that must have been my fault, there was a round in the chamber when I tried to feed another. I fixed my error and I'm wondering if that round was a dud.

I'm starting to question myself on exactly what was happening. I would chamber a round, shoot and then the bolt would be forward but the next round wouldn't fire. I tried to chamber another and it didn't feed, bolt getting caught on it (see the pic below). In some instances this happened when I shot, and others when I racked it myself. This was every time and I never fired more than 1 round without having to deal with the issue. If I got a round in the chamber by releasing the bolt, it would fire. But never seemed to chamber a round when I fired.

Any suggestions? I'm hoping it's the not the ammo as I spent a lot on it. Perhaps it's the fixed mag that's the issue. Open to suggestions.

Oddly my best friend had something similar happen while I was visiting him last month at his house in OK. His AR47 did the same thing, although he doesn't have a fixed mag.

The only thing we could figure out was the AR just did not like the steel cased ammo. After trying multiple brands of steel cased and getting all kinds of FTF and FTE we tried brass ammo and it didn't have any hiccups at all.

I would say try some brass ammo and see if that helps. If it is the ammo I would imagine you could sell the steel cased stuff on Armslist pretty easily.

From what I'm reading it looks like the rifle is short stroking. When I picked up the gun the guy who built it was tightening the castle nut, and said, "almost ready just torquing the buffer tube" or something like that. So I'm wondering if he put this too tight, as that can be a cause of both the failure to feed and not locking back on last round.
Is there a torque spec? I'll order a castle nut wrench now, there's a link in the lounge currently.

My opinion it is the buffer. Buffers are available in different weights. Perhaps the buffer is to light allowing the action to progress to rapidly. You may want to first take it back to the builder and if he/she wont fix it then order a different buffer. You can even buy them that has a system where you can add weight a little at a time. Good luck.

quote:

Originally posted by frayedends:
From what I'm reading it looks like the rifle is short stroking. When I picked up the gun the guy who built it was tightening the castle nut, and said, "almost ready just torquing the buffer tube" or something like that. So I'm wondering if he put this too tight, as that can be a cause of both the failure to feed and not locking back on last round.
Is there a torque spec? I'll order a castle nut wrench now, there's a link in the lounge currently.

Unlikely that’s the problem. Torquing the castle nut just keeps it from loosening and the buffer tube starting to unscrew. Unless you somehow crush the buffer tube enough that the buffer won’t slide in it, it’s not going to cause a problem. I’ve never seen that.

What’s the barrel length and buffer weight? Have you tried different ammo?

But if you’re running into this problem even when manually cycling the action, then maybe it’s something else. What do you see looking through the ejection port when manually cycling the action? Does the bolt go back far enough to clear the rear of the round? Does the mag follower push the round up high enough for the bolt to catch the rear for feeding? It could be a feeding problem with the mag.

I have an AR that has never had a single malfunction with any brass-cased .223 or 5.56 ammo I have ever shot through it (thousands of rounds).

It won't shoot three rounds in a row of steel-cased Wolf without short stroking and jamming exactly like in your picture (sometimes with failure to eject). Won't lock back on an empty mag, either.

I suspect Wolf is really underpowered or the cases stick in tight chambers or something. I'm sure it could be fixed with a lighter buffer, but I'm happy with how it shoots literally everything else, so I just don't try to shoot Wolf out of it anymore.

If I manage to find some brass ammo I’ll try different ammo. I’ll also take a bit more time and note exactly when it malfunctions.

Kind of hard to diagnose without actually seeing the gun, but the first thing I'd check is how the mag is seated in the gun. I've never dealt with a fixed mag lower before....do you have to separate the upper and lower to load it? How is the mag "fixed" in the gun? Is it inserted to the proper depth? Does the gun chamber, extract, and eject rounds when you cycle it manually? Is there any binding or resistance felt when cycling it by hand?

If all of those things check out, I'd say the next step is to try different ammo. It sounds like others here have had problems with wolff ammo in the past. IMO unless it's a match chamber or something, an AR should eat anything you feed it...all of mine do. I e shot plenty of wolff and Tula through my personal rifle, and we had a whole case of steel-case crap that somebody at the PD bought one time and we ran that stuff through a whole bunch of different ARs (including some actual M16s) without any problems. I guess it's possible that the batch you got is worse, but the AR is a very reliable platform that should tolerate it unless it's just absolute junk.

Wish you were closer...I'd happily meet you at the range and provide some ammo to run through it.

Some new semi-auto firearms experience cycling issues. It happens to ARs, shotguns, and pistols. Try another range trip with more powerful ammo and a well-lubed BCG.

I don't think steel-cased ammo per se is the issue. Wolf is just loaded pretty anemically, and often doesn't play well with new and dry rifles.

I’ve almost never had to break in any of my semi-autos, especially ARs. They went bang first time, every time. But, I don’t use steel case ammo in anything except AKs.

If you have to “break in” an AR, either there is something wrong with the gun, or you’re using bad ammo.

If you find that it's not ammo related, I'm gonna go with under-gassed or wrong buffer weight. Could also be an issue with the carrier key (it would be obvious if you look at the staking and see carbon built up around the base).


May be caused by worn gas rings too. To check rings, pull the bolt carrier group out of the gun, ensure the bolt is in it's forward position and stand it up on a table (on the bolt face). If it falls freely (or with little pressure), your rings are toast (cheap fix). If it stands on end without falling down, no problem.

I'd try to find out what gas block and gas tube was used. If the gas port is undersized, you'll experience this issue. Can happen if the gas tube is misaligned as well. Good luck.

What ammo do you ran the first time?

It sounds more like failure to feed the steel cases .

Explain "fixed mag"--does that mean you have to open the rifle to load the magazine. If yes---> may be a problem with the follower or mag spring. That can also explain the last round bolt not staying open. May just need new spring and follower. I assume a Mass 10 round mag limit?

My guess is an ammo issue and possibly a lubrication issue.

Thanks for all the suggestions. It turns out I do have a couple boxes of brass cased that I forgot I bought. I have some things to check and when I get out this weekend I'll look at everything you guys have suggested and get a better description of the issue. I will lube it more also. The videos I've watched show very little lube needed so I didn't go overboard. Also the class I had at Sig showed little lube needed.

As far as parts wear, this is a new rifle. So far less than 40 rounds I think, so nothing should be worn out. I'll update as soon as I have more info.

Is this a piston or a DI upper? I’ve never heard anyone say that only a little lube is needed on a DI AR. Much more often people say they like to be run wet.

quote:

Originally posted by Dwill104:
Is this a piston or a DI upper? I’ve never heard anyone say that only a little lube is needed on a DI AR. Much more often people say they like to be run wet.

Agreed, especially the BCG. This has been my personal experience, and was re-enforced in the Sig M400 armorer course I took 2 weeks ago. It doesn't have to be spraying oil everywhere, but metal to metal contact points should be wet. I typically oil the insides of the upper receiver where the BCG rides, the bolt lugs, gas rings, and pivot pin.

Yes that’s what I lubed. But they showed just a thin coat and it was much less than I’m used to with pistols. I will lube it up and have more info this weekend. Maybe sooner if I can get out there after work.

The need for minimal lube on ARs seems to be the most common misconception about the guns there is for some reason—as if there were prizes waiting to be awarded for getting away with that. The only times I’ve seen an AR malfunction if it wasn’t poorly remanufactured ammo or problems with a magazine was because the gun was dry; and whenever a dry gun was lubricated properly it started working just fine. Although I have no experience with steel cased ammo, I would expect that using it would make lube even more important. I hope you figure out what’s causing your problems, but I concur with the recommendation.

I think the overlubing concerns may have originated in dusty environments (like Iraq) where fine, gritty sand getting into everything and stuck in the lube is an issue. For the average American who just shoots the thing at the range, cleans it, and puts it away in the safe (or even cops, who shoot it, hopefully clean it, then put it in the rack in the patrol car), it's not going to be an issue. If you lube it too much, the excess will fling off and make a mess...but the gun will run. Too little and you're looking at premature wear and possibly malfunctions.

A smooth-running AR is like good sex: Clean or dirty, it's gotta be wet.