When You Have an AR Feed Failure — What Is Your Diagnosis?

Posting on the 6.5 Creedmoor Group Facebook Page, Russel T. complained that his AR magazine doesn’t like to feed that last few rounds. Russell asked: “Full magazine, no problem cycling. But with five (5) or less in the magazine… this happens. What can cause this?”

It sure looks like he could use a new magazine spring, but there may be buffer-related problems as well. Or maybe a gas system issue. What’s your call? Here are some responses posted by Facebook folks:

“Weak mag spring.” — Josh N.

“Weak mag spring or too heavy of a buffer spring.” — Justin G.

“Try a different mag, if it still jams it’s probably a gas problem, if not chuck the bad mag.” — Otto G.

“Weak mag spring or literally anything that would cause the Bolt Carrier Group to short cycle.” — Reggie W.

“I’ve had the same issue with my 300 BLK when my buffer tube came apart. It would still cycle cheap rounds fine but [not] the Hornadys. Took it apart and found the buffer tube was in pieces.” — Hunter R.

“Could be a weak mag spring or buffer spring, both at the same time.” — John S.

“As mentioned it could be a list of things. However, bolt velocity is too fast/hard and the usual (but not always) culprit is over-gassing.” — Bill F.

“Short cycle — clean and LUBRICATE the weapon.” — Mark H.

“Look to see where the brass is ejecting. That will tell if it’s an over or under gas issue. If that’s ok then look at the mag spring. See Diagram” — Teddy G.

“Weak magazine spring, I tossed four brand new ‘bargain mags’ [due to] that very problem.” — John V.E.

“May not be a weak spring or bad mag. Check out a Tubb Precision flatware spring. I swapped mine in a new rifle and solved the problem of short stroking and double feeds.” — Anthony T.

“It might be the follower as well, some designs will dip in the front/rear as rounds are expended. It’s the reason why we didn’t use some service mags with the green followers.” — Chris J.

“Weak spring… time for a new magazine…or add a 5-round block and make it a 25-round magazine. But I’m positive it’s a weak spring, which means it’s just a matter of time for failure.” — Steve M.

“Without the weapon in hand I would hate to guess….
Start with the simple stuff and go from there. Trying to diagnose a problem from a photo is just like when your wife or girlfriend tells you the car won’t start. LOL.” — Mark T.