It works, you have to keep constant pressure so the bullets don’t fall

I hear they need to be supersonic to work

Need 120gr or less

I always buy 300 black outmags for my 300 black out.I always have issues with 556 mags

You have to use a smaller grain 110 125

I've seen it done... I can't do it.

Those ribs/guides that are touching bullet, are meant to guide the much smaller 556. If you can shave those down by sticking a file or sharp wood chisel in there, it will let the 300 blk bullets rise freely. But yeah, anything more than 125 grain will be too fat.

Ive had 3 Magpul D-60s that will suddenly and instantly unload themselves and spray 60 rounds all over the damm place.

Mine isn’t reliable w .30@ BLK. It’s too temperamental for any use other than for plunking.

Change the follower to a .300 black out and shave the slides guides line down on the mag

I checked and it seems the D 60 is not 300blk compatible. The 30 cal bullets are too big to feed thru the magazine properly. Sorry man.

What’s the best ammo for it? I’m looking to get the same brand

Got it to run good or still meszing up?

because it's for 223/556

Disassemble the mag and buy newer or better components for the mag and feeding process.

dude you are the only person on you tube that is having trouble so its probably a bad mag.

110 grain only dummy, heavier .300 is a longer bullet than supersonic

hows it work now?