First Malfunction

[No Bananas]

I have a 12.5" SBR. RRA Lower and internals, H buffer, Semi BC properly staked (yes, if I could go back, I'd get a FA carrier), +5% SS extractor spring, DD M4 9" rail, Denny's/GTS Operator barrel, GI front sight post/gas block cut down to fit under the rail. All work done and assembled by ADCO. They did great work. I've shot just about 1000 rounds of ammo through this gun, many different types and bullet weights (excluding any steel cased stuff). I was using a Bravo Company aluminum mag w/ CS spring and magpul anti-cant follower. Had the mag for a couple years, no issues. The gun was lubed, hadn't been cleaned in a few months, and had not been shot in a few months. It wasn't really dirty or anything. Never had a malfunction with the rifle before this. I'm trying to not let this shake my confidence in the gun, and tell myself that malfunctions can happen to any rifle...right:fie:?

I was shooting Silver State Armory 5.56 77 gr. SMK loads. I got a FTF. The bolt had slammed on a cartridge just below the shoulder, leaving a large dent, and rendering the round unfireable. The malfunction occured right about the feed ramp area. After I removed it, I saw a long scratch on the opposite side of the dent. It began just foward of case head and twisted a little bit, with some chips of brass still attached to the etching of the scratch. What likely happened here? Was it the ammo, the mag, or something maybe with the gun? I fired 40 rounds of this stuff back in January with no problems. I have fired other 5.56 (as opposed to .223) in this gun without issue. The WWB 5.56 rounds, and the Prvi Partizan M193 5.56 rounds. I went on to shoot BH blue box 69 gr. match, Hornady TAP (75 gr.), PMC 55 gr., Federal Gold Medal 69 gr., and Buffalo Bore 77 gr. .223 ammo with no problems, using the same mag and some Pmags.

Thanks in advance.

[rushca01]

Really sounds like a mag issue. Replace the mag and drive on.

[marco.g]

Sounds like a bolt override. Had this happen a couple times to my bcm 14.5 middy. Im running USGI mags (NY state) so i switched them to magpul followers and the problem went away.

[devildogljb]

id have to agree with rush it sounds like a mag problem. Try the mag again with the same type of ammo and then a different ammo if it keeps happening its def the mag

[P2000]

Tagged for interest.

The only jam I have had (only fired less than 2k rounds) sounds like the same exact thing and happened with a pmag. But I had around 300 rounds through that pmag before it happened. Since then I have noticed that much of my brass has two scratches on it. I can tell that the scratches are coming from two adjacent locking lugs at 6 o'clock because it is about 90 degrees from where the extractor made a slight marking on the brass. It seems to do this with several types of mags.

My thinking is that lots of the brass scratches by that area, but only this one round dug in enough to stop the bcg for some reason. I took a small file to the sharp edges of the locking lugs, and that seemed to make the scratches on the brass become less apparent.
Hopefully it doesn't happen again, and I have retired that mag.

Have you noticed scratching on your brass too? I'm sure someone knows more about this type of situation. Could it just be that some locking lugs are too sharp? (Mine is RRA, so it may be out of spec)

[usmcvet]

I would not worry about it. One malfunction in 1,000 rounds and it is likely magazine related. Those are good numbers.