AR15 - 223 - Hard Primers/Light Hits

[JoeH]

I took my new AR out today for the first time. I was getting a failure to fire in about 30%-50% of my rounds!

Upon inspecting the primers, I found light - very light hits on the rounds that failed.

Mac was there and generously gave me 30 rounds of his ammo (he said it was just mil-surp stuff). All rounds fired fine.

I was shooting PMC ammo which I'm told has hard primers.

I want to get my gun to work with the PMC for two reasons. One is that I bought 1000 rounds of the stuff. The other and more important is that this is a battle/SHTF rifle. I want it to work with any ammo I feed it.

So, what do you AR gurus recommend?

Thanks!

[ttousi]

get rid of that PMC stuff.........Drop it off and I will dispose of it for you.




Actually have not had any issues with the PMC myself.........haven't shot a large amount but it's gone bang in several guns. FWIW

[onebohemian]

What brand AR is it?

A weak hammer spring can case light strikes. I added a JP hammer spring to my trigger group and it wouldn't reliably fire Wolf primers. Worked fine with decent ammo but not with the wolf. I put the stock spring back in and no problem whatsoever with the wolf. Do you know what spring you have in your rifle?

If you are seeing inconsistent hits, maybe your firing pin is sticking in the bolt. Have you pulled the bolt apart and cleaned it?

[hammAR]

get rid of that PMC stuff.........Drop it off and I will dispose of it for you.




Actually have not had any issues with the PMC myself.........haven't shot a large amount but it's gone bang in several guns. FWIW

I fully agree, my Colt's eat anything that gets near them......

you must not have a Colt.... .......

[westberg]

I shoot a lot of PMC through my rifles, the JP has the red and yellow springs which are recommended for hard primer ammo. The Wilson has both yellow springs which are a lighter pull and again no problem. So a standard trigger springs should work if that is what you have. Are the bullets seating all the way in, no burrs or anything.

[SIGP240]

Yank the carrier, pop the cotter key and get that nasty greasy firing pin out and clean it. Then with the right brush, give that firing pin way a cleaning, same with bolt. I even use a leather shoestring and Mother's. I even boil mine with non-sudsing detergent. The spring has to be surgically clean, too.AND OEM Then, only then (when dry) oil with one drop non temperture sensitive lube. All 7 of my AR's behave like yours in the winter. I know, because after the first 100 rounds "warm-up" the gun behaves like it does in warm weather. Also, DPMS bolts are semi-unfinished with tooling marks, radii and a lot of texture you will not see if you spend a little change on a Smith Ent or a Les B. "Match" bolt. You can trick up to Wolff high power hammer spring, but give Yellow Tavern Red. Power sear/trigger springs a try. Best three bucks to spend without dropping ching on Jard 1.5# trigger. I don't know too much about reduced mass hammers, but the dill press treatment can save you 35.00$ in about 2 min. More bang for the buck. I have a sneaking suspicion that is may not all be the fault of PMC brand, as they subcontract for other brands around the world and more shooters would have more complaints as a result. If you have a parts gun, be cautious or hasty assembly and burred chambers. If you are using XM177 Fed in a 223 barrel, read the warnings. The bullet ogive may be engraving with the lands.

[macphisto]

Joe, all the PMC stuff you gave me in return went bang.

[Pat]

I have a whole set of springs you can have. There're left over from when I swapped out everything for a Chip McCormick trigger group.

As to the PMC stuff, I also bought a few boxes. At 50 yards, it was hitting the target about eight inches low of my "regular" ammo, Remington UMC. That's 16 MOA low, brothers! I wonder what it would crony out at...?

[JoeH]

I'll start with a good cleaning and go from there.

It's a Del-ton upper on a Territorial Lower (LPK from Randy too). I did not do a complete bolt cleaning before running the gun for the first time.

Pat, as for hitting low, the PMC hit the same as the stuff Mac gave me. So, it should be good to go.

HammARgh, if a Colt was in my price range I would have bought a Sabre

[hammAR]

HammARgh, if a Colt was in my price range I would have bought a Sabre

..................me too....Colt 6920............Sabre Defense clone is overpriced.......

most of my AR's are random parts put together with bailing wire, duct tape and JB weld, and assembled just using a claw hammer and a big wood chisel......

[cobb]

most of my AR's are random parts put together with bailing wire, duct tape and JB weld, and assembled just using a claw hammer and a big wood chisel......

And I bet they go bang with PMC ammo. PMC is about the only factory ammo that I shoot in an AR. True my handloads shoot better, but all of the PMC went bang in my Bushmaster, Rock River and S&W.

So Joe, it really seems that it may be a rifle problem, but there is always the possibility of a bad lot of ammo that is finicky and works in one AR and not another. Let us know if you find a definite cause in the AR, if something simple, it is nice to know to maybe take some proactive actions on our own rifles.

As you mention, a complete cleaning might be a good place to start.

[Pinnacle]

I have seen sonetimes that light hits sometimes equal bolt just a few thousandths out of battery... Try scrubbing out the Chamber and cleaning the lugs.

[westberg]

JoeH,
Have you figured anything out on the problem you were having

[JoeH]

Ron-

After doing a little research, I was able to ascertain that the hammer spring was installed incorrectly by the manufacturer.

I fixed the issue and everything should be good to go.

[westberg]

Ron-

After doing a little research, I was able to ascertain that the hammer spring was installed incorrectly by the manufacturer.

I fixed the issue and everything should be good to go.

Thanks JoeH for the update, do you know who assembled it....