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A buddy of mine has a custom ar10 that's got some feeding issues that i thought i'd run by you guys. its an armalite ar10 in 6.5-284, armalite upper and lower, jp adjustable gas block and noveske stainless barrel. The issue is exclusively a failure to feed. It ejects just fine but will have a ftf every round or every other round. Some of the rounds it tried to feed so hard that it dents the brass. Any ideas?






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If he's already tried different ammo. The first thing I'd do is try a different magazine. If he only magazine make sure the follower is free and moves without issue, maybe some lube and then try putting only two or three rounds in and see if it still FTF. If it's not the mag examine the loading ramp for any obvious anomalies would be next.

The follower on that mag appears to be canted forward, that could be the issue.I would try another mag for starters.

Carry-a-Kimber wrote:The follower on that mag appears to bed canted forward, that could be the issue.I would try another mag for starters.

I'm not an expert, but that follower looks wrong to me.

That is what we thought too. Here is the deal though: All the mags look like that. when you put a round in the magazine, the follower sits at a more correct angle. Empty, and the magazine looks funny.

To answer your questions, this is the only magazine he has. We pretty much decided that it was going to be a magazine issue, but we wanted to post up here and let all the Gun-Guru's look it over and see if they spot a glaring error.

Notice in the pictures that the front of the bolt gets stuck in front of the rim. Is this also probably magazine related?

Dave2 wrote:

Carry-a-Kimber wrote:The follower on that mag appears to bed canted forward, that could be the issue.I would try another mag for starters.

I'm not an expert, but that follower looks wrong to me.

I, too, thought it looked odd, though I've never seen a AR-10 mag. It just doesn't look right. Many FTF are mag related. AR-10 guys - time to chime in.

puma guy wrote: Many FTF are mag related. AR-10 guys - time to chime in.

Don't know much about specific issues for that gun/caliber, but FTF issues always make me check the magazine.

snatchel wrote:That is what we thought too. Here is the deal though: All the mags look like that. when you put a round in the magazine, the follower sits at a more correct angle. Empty, and the magazine looks funny.

To answer your questions, this is the only magazine he has. We pretty much decided that it was going to be a magazine issue, but we wanted to post up here and let all the Gun-Guru's look it over and see if they spot a glaring error.

Notice in the pictures that the front of the bolt gets stuck in front of the rim. Is this also probably magazine related?

Do all the mags look like that or is this the only mag he has? Are the other mags yours? They also have FTEs?

C-dub wrote:

snatchel wrote:That is what we thought too. Here is the deal though: All the mags look like that. when you put a round in the magazine, the follower sits at a more correct angle. Empty, and the magazine looks funny.

To answer your questions, this is the only magazine he has. We pretty much decided that it was going to be a magazine issue, but we wanted to post up here and let all the Gun-Guru's look it over and see if they spot a glaring error.

Notice in the pictures that the front of the bolt gets stuck in front of the rim. Is this also probably magazine related?

Do all the mags look like that or is this the only mag he has? Are the other mags yours? They also have FTEs?

I can see how that would be confusing! His ony mag looks like all of the aftermarket mags we compared to online.

snatchel wrote:

C-dub wrote:

snatchel wrote:That is what we thought too. Here is the deal though: All the mags look like that. when you put a round in the magazine, the follower sits at a more correct angle. Empty, and the magazine looks funny.

To answer your questions, this is the only magazine he has. We pretty much decided that it was going to be a magazine issue, but we wanted to post up here and let all the Gun-Guru's look it over and see if they spot a glaring error.

Notice in the pictures that the front of the bolt gets stuck in front of the rim. Is this also probably magazine related?

Do all the mags look like that or is this the only mag he has? Are the other mags yours? They also have FTEs?

I can see how that would be confusing! His ony mag looks like all of the aftermarket mags we compared to online.

Whew. Just so I know it wasn't me. I would definitely get another mag to try out. Besides, one mag is never enough, is it?

I'll look at my mags when I get home and see at the folllowers looks like.

Based on where the bolt is catching the round I want to say that the gun is short stroking. Since he has the adjustable gas block, where is it adjusted at?

after getting home and reading up on the gas block it appears we had the screw adjusted way to far out. almost all the way out! JP's website said to screw it all the way in then back out two turns. so i'll try that and see how it does, thanks for the info guys.

First thing I'd try is a PMAG to see if that would work, but I don't know if Magpul makes one for an Armalite rifle. Next thing I'd look at is the barrel installation. My AR10 has a stainless 18" Noveske heavy barrel, which was installed and headspaced by Noveske into the existing DPMS upper. One of the things that Noveske did at the time was to also machine some extended feed ramps into the upper receiver—just like the extended M4 feed ramps—to increase feeding reliability.

I have had some difficulty finding loads my rifle likes, and I have also had a bit of difficulty adapting myself to the larger AR platform and shoot it well, but I have had zero reliability issues, even with handloads that were so hot that they blew the primers clean out of the primer pocket.

Most rifles cycle faster than necessary, and the resulting “bolt slamming” effect is a noticeable part of the recoil impulse.
The main purpose of our adjustable gas block is to allow you to adjust the port pressure to the operating system, thereby finetuning
the bolt velocity, which will result in a smoother shooting rifle especially if you already have a JP Recoil Eliminator or JP
Compensator. Additionally, the JP Gas Block is also useful in obtaining optimum port pressure on otherwise difficult to run
setups such as suppressed weapons, short-barreled weapons, or unusual chamberings for nonstandard cartridges.
To adjust for your load, turn the gas adjustment screw in all the way to close it off. Then, back it out approximately two full
turns, and load one round in the magazine and fire. If the bolt holds open, the gas block is set. If the bolt does not stay open,
it is short-stroking, and the valve should be opened about another half turn. Continue backing the gas adjustment screw out
until the bolt holds open consistently on last round. Test this again with one round in the magazine.


ok i tried these instructions per the jp website. i put one round in the mag and adjusted the gas screw to two turns out, chambered the round, fired and it held the bolt back. I repeated this same test with 2.5, 3, 3.5 and 4 turns out and they all held the bolt back. I repeated this test with one round in the chamber and one in the mag with same numbers of turns on the screw. It would not chamber the second round with any of these settings. I guess my next step is a new mag.