Took the .300blk pistol out to try and figure out why it was misfeeding sometimes. I think it's related to magazines.

Some of my PMAGs it goes through flawlessly, as fast as I can shoot. But on two out of five, it'll misfeed. Even when I reduce the number of loaded rounds (I kept them loaded 25 each), the two miscreant mags would screw up.

Anyone else have this issue? Is the solution to go to the .300 specific mags?

I have experienced no issues with either gen 2 or gen 3 pmags on supersonic 300blk ammo. I have not tried pmags with subsonic ammo, although I have heard the long subsonic bullets do not always play well with some pmags.

Soon after I bought a 300blk upper, I converted to aluminum mags for all blackout shooting. I also use only plastic mags for 223 shooting. My reasons are twofold:
- reported feeding issues with the heaviest 300blk bullets in pmags
- efforts to eliminate mixing calibers in guns

Yeah, I should have clarified. Shooting 200g S&B subsonics. I use smoke Lancers for 5.56 and FDE PMAGs for .300blk. I have to come up with something else then.

Allen - I do the opposite of what you described. I use the Lancer standard mags for my 300 B/O rifles with 208gr A-Max and 220gr lead rounds, all sub-sonic, and thru three different AR’s with I would guess 1500 rounds thru the three total I have not had the first FTF or FTE and my bolts lock back everytime.... I use the 20rd mags most of the time but have used the 30’s also with no issues....

Hope this helps Sir....Might want to give your Lancers a try....Mark

I'll just leave this here....

quote:

Originally posted by sigarmsp226:
Allen - I do the opposite of what you described. I use the Lancer standard mags for my 300 B/O rifles with 208gr A-Max and 220gr lead rounds, all sub-sonic, and thru three different AR’s with I would guess 1500 rounds thru the three total I have not had the first FTF or FTE and my bolts lock back everytime.... I use the 20rd mags most of the time but have used the 30’s also with no issues....

Hope this helps Sir....Might want to give your Lancers a try....Mark

I'll second this.

I use FDE Lancers in my 300 BLK guns...they also have FDE furniture.

I used other color Lancers in 5.56 rifles for various loads, also matching furniture. Priority is clearly to avoid mixing BLK and 556.

6.5 Grendel is steel/aluminum magazines and the whole receiver is FDE.

As far as function, I've had no issues with function from a Lancer/300 BLK combo.

That slow feed seems exactly what is going on with mine.

You all say the Lancer 5.56 mags work well with the .300?

I can’t say I’ve had any issues with any Gen of Pmags however I am slowly switching over to the lancer 300 blk mag. If purchasing new mags for the 300 might as well purchase the mags designed for it. The 300 designated mags where designed to work with the heavy subs that have had issues in some pmags and lancers. Neither company have issues with supers in the 5.56 mags.

Allen - Yes Sir. I use the Lancer 5.56 mags with my 300 B/O set ups...

Sorry I did not state that in my earlier post....Mark

That vid is probably your issue. When Magpul came out with the 300blk mags I thought it was marketing. I haven’t had a single issue with my 556 Magpuls and I shoot a good bit of 300, it’s my favorite rifle caliber.

However, I’ve now seen enough posts on the internet like yours to be convinced it’s a real thing.

Seems like some are lucky and some aren’t.

I typically buy metal metal mags over pmags due to bulging anyways, but this is one more reason to go old school metal mags imo.

Yeah, I played around with my current PMAGs, stripping a round out and seeing what happened. Most did what those in the video did.

So I've got 14 .300blk specific PMAGs on the way. Only downside is they are are black. My Lancers for the 5.56 are smoke, so visibly they should still stand out from the PMAGs. And they will still feel complete different, so it'll do.

Watch the video above, buy 300 blk specific magazines from Magpul, and your issue is SOLVED!! Easy as pie.