Feeding issue when bolt is locked to the rear

[Valjean]

New Grendel AR has been having issues cycling. If I charge the weapon manually, it works fine. I've tried locking the bolt to the rear and inserting the mag before hitting the bolt release. Have had a few FTFs (couple no round picked up, couple jams against the top of the chamber (round entering the chamber at too steep of an angle)). The magazines appeared to have been seated fully.


Any ideas?

[Sputnik]

Try a different mag, some are touchy.

[A5BLASTER]

Set that mag to the side and try some of your other mags. If the problem goes away. Then it is that mag, if it happens with moat are all of your other mags then it is something wrong with the internal parts are the lower is out of spec somehow.

Who's mag? ASC?Elander?CPD?

Who's lower?
Who's lower parts kit?
Who's upper?
Who's bcg?

[VASCAR2]

With the larger case head on the 6.5 Grendel compared to 5.56 cartridges occasionally the ejector can contribute to feeding issues. If the ejector spring in the bolt is very strong and there is no bevel on the edge of the ejector this can contribute to feeding problems. There are videos on youtube showing how to modify the ejector but here is a link describing the problem. This mod may have no effect in your rifle and you might be dealing with a mag issue. Just something to be aware of.


http://bulletin.accurateshooter.com/2014...artridges/

[Valjean]

Set that mag to the side and try some of your other mags. If the problem goes away. Then it is that mag, if it happens with moat are all of your other mags then it is something wrong with the internal parts are the lower is out of spec somehow.

Who's mag? ASC?Elander?CPD?

Who's lower?
Who's lower parts kit?
Who's upper?
Who's bcg?

The Mags are ACS and AR Stoner.

All of the other parts are PSA.

[grayfox]

+1 on try another mag. Especially use a worn-in one... if possible borrow one that's broken in from a buddy.
You can also disassemble one of your 6.5's and put the internals into a 556 mag case. Sometimes new mags need some smoothing out of the inner edge of feed lips or the follower may have a piece of plastic/flashing that's causing some binding at the lower force of mag-release-feed.

[Wanderson]

Unless something’s changed, AR Stoner mags are made by ASC.
So same mag.
I’d try a CPD or E-Lander.
FWIW my PSA 12” upper runs Hornady Black & Wolf steel in E-Lander & CPD mags without any misfeeds at all, even during break in.

[A5BLASTER]

The Mags are ACS and AR Stoner.

All of the other parts are PSA.

I hear good stuff about PSA parts and weapons just don't have any first hand experience with it.

Arstoner is asc mags. I would order up a CPD mag and see what it does if it still messes up maybe look at the gun for something out of spec are not installed correctly.

[Happy2Shoot]

I have a PSA 12.5" and I use ASC magazines exclusively. No problems. CPD mags are bad news. The face of the mag is too tall and catches on the brass case mouth as the case slides out of the mag during feeding. Had to dremel.

[A5BLASTER]

I have a PSA 12.5" and I use ASC magazines exclusively. No problems. CPD mags are bad news. The face of the mag is too tall and catches on the brass case mouth as the case slides out of the mag during feeding. Had to dremel.

I think your the first person I heard say that about a CPD mag.

Typically it's the ASC mags that you habe to do that to. I know I had to dremel down all of my ASC mags bit not any of the CPD mags I had.

I have since moved on to a completely diffrent mag setup but CPD mags were the best of the best for me in metal mags.

[Happy2Shoot]

Can't leave us hanging! What is you new mag setup?

[A5BLASTER]

Can't leave us hanging! What is you new mag setup?

Six8 pmag

[ErikS]

I dremel all my Grendel mags for that very reason. As was stated try some broken in mags. I have best luck with 17rnd E-Landers. Of note, I think the E-Lander mags are the only thing I own that are were made in Israel.

[Valjean]

Turned up the gas and went to the range again yesterday. No FTF, but I did notice a couple of times where the bolt release caught the bolt in a funny way on the last round. In these instances, the bolt wasn't caught all the way back., and when I inserted a new magazine, the bolt head was pushing down on the base of the first round in the magazine, causing the tip of the round to angle upwards. When this happened, the bolt release was in a weird position between it's normal (unpressed) state and it's depressed state. I had to beat on it a little to get it into normal function...felt like it was sticking a bit.

[Growler]

This is beginning to sound like a gas problem, as in not enough.

Are you certain the gas block is aligned with the gas port?
What ammo are you using? Barrel make, length, and gas length?

[gwtx]

I have a PSA 12.5" and I use ASC magazines exclusively. No problems. CPD mags are bad news. The face of the mag is too tall and catches on the brass case mouth as the case slides out of the mag during feeding. Had to dremel.

I have 10 rounders in CPD and Elander. Had to dremel the front of the Elander, CPD was fine. Go figure?
I also had an undergassed situation. Drilled out the gas port .002", switched from ARCOMP to CFE223, and so far the problem has not happened again. I have an 18" bbl with rifle length gas. Port was .094, drilled to .096. Good luck

I just re read this old post of mine and wanted to clarify a bit. Drilling out the port "helped". I had only a few FTF's after this, but, it seldom locked back on last round.
I read a post from a fellow member saying that he had cycling problems with ArComp and switched to CFE223 and the problem went away. I switced, and the problem went away. The accuracy is not as good yet, but it cycles flawlessly now. Just need to work on my load. I would rather shoot ArComp because it is MUCH cleaner that cfe223.