View Full Version : Issues AC-556 with new Ruger 30 round magazines?

June 23, 2011, 01:00 AM
Has anyone had any experience with running an AC 556 with new (recent manufacture) Ruger branded Mini 14 30 round magazines?

I recently purchased an AC 556 and have had the bolt jam several times. It is my observation from internet searches is that the only common cause of malfunctions with this gun is inferior magazines.

I have been using new manufacture 30 round Ruger branded Mini 14 magazines. I have been saving the new old-stock Ruger magazines I have aside since they may have more value as brand new someday should there be another hi-capacity magazine ban. (Labled as gov't/ law enforcement use only...)

I would use these if necessary to keep the gun firing properly, but curious if there might be a different issue unrelated to the magazines.

I am using brass PMC .223 new ammo.

Gun is clean and lubed...

Any help/thoughts appreciated.


June 23, 2011, 09:19 AM
Where exactly is the bolt hanging up, and when? Is it on the ejection stroke, or the return stroke, and does it stop at the same point each time? Does it happen ONLY in FA, or also in SA? This is a "debugging" program you have to work through one step at a time.

June 23, 2011, 09:34 AM
It's the magazine. I have an AC556. I don't have one of the new 30 round magazines. I have a couple of 20 round magazines, and 2 aftermarket 40 round magazines and a Betamag. One of the aftermarket magazines will need to have the feed lips adjusted (bent down a little) every now and then - the other aftermarket magazine never gives me any problems. The 20 round magazine works perfectly every time.

When I purchased the beta mag with the mini-14 feed tower, it fit so terribly that I could hardly pull the bolt back. At first I was reluctant modify the feed lips on it, but after reading other accounts of problems, I found that it was normal to have to trim the feed lips to get it to work. I ended up having to shave 1-2 millimeters off of each side, a tiny bit at a time. It works perfectly now, but I was surprised at how terribly "off" it was. I suspect that its the same thing with your 30 round mag. The bottom of the bolt actually has to pass through the feed lips.

This is the first I've heard about a factory mag having this problem. I really don't understand how hard it is to make magazines to specifications! The interesting thing is that the Mini-14 - AC556 is actually very forgiving - the magazines don't need to be perfect. It's just that there is so much slop out there in the way companies (maybe Ruger now included) manufacture their magazines.

June 23, 2011, 10:57 AM

I am headed out to observe jamming more carefully this weekend. I will be trying some of the old Ruger mags as well. At least one time spent shell was being pushed back into chamber, seemingly along with 1 or 2 more rounds.

Skans...this is what I am thinking as well, just confirming with other sources, like this forum.


June 26, 2011, 09:54 PM
Verdict is chipped/worn front magazine latch, which I replaced before shooting.

7 magazines fired flawlessly today.

June 27, 2011, 09:09 AM
Thanks for telling us the problem - I wouldn't have guessed a worn magazine latch, but that makes perfect sense. That really would make it look like you hare having a magazine problem. Even thought mine runs flawlessly, I'm going to have to check that.