Magazine FTF question

[Trapper]

I have been shooting my 6.5 Grendel using the 123 gr. Hornady Amax round. I am having an issue with the second round not wanting to be stripped off the top of the magazine and fed into the chamber. I have tried 4 different magazines from different manufacturers and still the second round does not want to feed off the top. The second part of the equation is that I have a low profile adjustable gas block and I am starting to think it may be related, if I am not getting enough gas pressure to back the bolt with the energy needed to make it come forward with the help of the buffer and spring. I am open to any thoughts and suggestions.
Thanks in advance

[leopard6.5]

Hi Trapper: What bolt carrier group, buffer weight and spring are you using?

Thanks for the additional info.

Lee

[Trapper]

Thank you Lee for responding.

The upper is a standard AA 18" upper with the Lothar Walther barrel. The Bolt carrier group is the standard that came with the upper. The lower is a Rock River arms complete lower except for a Gieselle trigger group. Mags tried were everything that Midway sells in 6.5 grendel and even the original AA magazine. The buffer and buffer spring are standard mil-spec that came with the lower. I have not changed them out. I think that the adjustable gas block may be the problem but I lost the darn instructions on which way to adjust the little hex screw to get more gas thru the tube to push harder on the BCG. I have read other threads where guys have polished the small extractor plunger in the bolt face, but it always feeds the first round if it is locked back and you insert the magazine and fire the round, then it will not stripe off the next round. Change mags and let the bolt go home and it fires the first round and will not stripe off the next round. I am hoping that I do not need more than 1 round to kill what I am shooting, but if I wanted it this way I would have bought a bolt action.....

[leopard6.5]

Trapper, AA hasn't sold an upper with a Lothar/Walther barrel for years. How old is the upper? Was the upper bought directly from AA?

Do you know how to tell if you have a M16 bolt carrier or an AR15 bolt carrier? The M16 bolt carriers are heavier.

What weight buffer are you using?
Do you have an adjustable buttstock? If so you probably have a carbine buffer that is lighter than the recommended approx. 5.2 ounce buffer.

The reason I'm asking about these items is to eliminate them as a cause of your problem to narrow it down to just the magazines which could be the magazines feed lips.

Can you post pictures of your magazines from the top, side and front especially the feed lip area?

Do you know what brand of gas block you have?
If it's a PRI you can probably go to their website to see if it looks the same as you have and find instructions.

Thanks for the additional info.

Lee

[Sojorboy]

Will the rounds feed manually ?

[LRRPF52]

If it isn't cycling the action far enough back to pick up the next round, it isn't the mags at all, it is your gas system. Just back out your gas block adjustment screw counter-clockwise. You'll probably need at least one full turn to get it running, if not more. I would try 2.5 turns, then dial it back down in half-turn increments until it short-strokes, then dial back out 3/4 of a turn.

Understand that you'll need more gas port diameter to run reliably in the lower temperature range, so a fine-tuned, on-the-edge of reliability but smooth-cycling action can go to a short-stroking FTF gun with a major drop in temperatures from your reliable temp range. I lean to reliable, so my adjustable gas block is almost wide-open.

When introducing a topic on problems, you might be better served in the trouble-shooting section. I would also title it: "FTF, need help in diagnosing", since magazines aren't your problem here. Short-stroking is almost always gas system related, which can be ammunition not providing enough gas or too much gas, or gas system components are out of whack in some way.

[Trapper]

Thank you all for the comments.

Actually I bought the upper from a member of the forum that had 2 alike and I was happy to take it of his hands.
LRRPF52 was correct, it was the adjustable gas block not being open far enough and was strangling the gas flow. Thank you all for your comments and suggestions. The mags all worked fine and the buffer and spring were mil-spec from RRA for a 5.56 but they too work fine now that the gas block is adjusted more to where it should have been. I always seem to learn things the hard way. As someone said on here one day, " a bad experience makes for good stories".
Thanks again

[leopard6.5]

Trapper, great to hear it was an easy fix.

Have fun and great shooting.

Lee