300BlkTalk

Magpul manufactures 300 BLK specific mags but only in the 30 round version. What limited information I have found says the standard AR15 mags are only an issue with the larger bullets and work fine with the smaller bullets, the problem being the rib in the magazine hits the larger bullet and causes it to shift in the mag.
Anyone have any direct experience with this? It would be nice to use 10 rounders, especially for bench shooting where the longer ones may interfere.

Lancer Mags work great. I have some 5 and 10 rounders I use for bench shooting all the time.

I just filed down the ribs on standard Pmags and they work great.

I have not had any problems with steel mags or Magpul 10, 20, or 30 round mags but 99+% of mine are handloads. The spring in the latest version of Magpul mags is a bit stiff for my aged fingers. I got an Uplula that took care of that. When it looked like Hellary was going to be elected, I stocked up. People like me panic buy, and then there is a drought in sales for the firearms industry. I still have a stripped lower I have not used from pre-election times. The reverse happened with suppressors.

I'm thinking of picking up a stripped lower and setting it back, just for "hard times". You just never know which way the political winds are going to blow.
Same thing with stockpiling brass, bullets, and primers. I'm not advocating panic buying and clearing the shelves, just enough to weather the next shortage because of panic buying.

rlandry6 wrote:Magpul manufactures 300 BLK specific mags but only in the 30 round version. What limited information I have found says the standard AR15 mags are only an issue with the larger bullets and work fine with the smaller bullets, the problem being the rib in the magazine hits the larger bullet and causes it to shift in the mag.
Anyone have any direct experience with this? It would be nice to use 10 rounders, especially for bench shooting where the longer ones may interfere.

D&H recently came out with 300 BLK specific magazines in 10, 20, and 30 round versions.

I've been using some 10 and 20 round versions off the bench (30's are a little too long) and they have worked with zero problems so far.

Lancer is making 300 BLK specific mags. Why... I have no idea, since the regular L5AWM's work fine with everything. I'm guessing marketing. But they have discontinued colors, I know the ODG ones are no more.

smustian wrote:I just filed down the ribs on standard Pmags and they work great.

Same here.

I did see what looked like a little bit of difference with the followers, but I was pretty subtle and I don'r see what that would have fixed if the issue was thr larger bullets contacting the ribs.
Did filing the ribs have any effect on operation with the smaller bullets?

Anything I have tried from 110-130 grain have all fed fine with sanded ribs.