300 Blackout Specific Magazines?

do those of you that shoot .300 blackout use the .300 blackout magazines from Magpul? Or do regular 5.56 mags work just as well?

I my experience the regular Magpuls seem "swell up" a little when loaded with 300BLK.

I am using both Magpul 300 mags and aluminum GI mags.

The Magpul 300 mags have been flawless and require much less tinkering with OAL. When I say less I really mean zero.

I was shooting supers out of a 7.5" with regular pmags just fine before I tried the other ones. They do feel smoother and a better fit in 300 blackout magazines. There is definitely a difference with the internals.

When I was researching them it seemed like the people who made the switch were having issues with their specific build and ammo types. Mostly with sub sonics. Someday my suppressor will come home and I'll have a chance to find out for myself.

There’s a little rib inside that keeps the cartridges aligned. It presses on the bullet. The BO specific mags have the size of that rib reduced to compensate for the larger diameter bullet. On mine, 5.56 mags were a total failure. After loading a few rounds, the stack of cartridges would bind and cause all sorts of hell. With the BO mags it runs like a sewing machine.

I took a file and worked that ridge down on several magpul mags to make my .450 Bushmaster loads feed properly. It took a few minutes, but they work without issue with that rib gone. I imagine, if the rib is a problem, removing it would work just as well for 300 BO.

Never had a problem shooting either factory (REM & SIG) or hand loaded 220gr or 208gr subs (9") or supers (16") using 5.56 pmags.

Not sure WTH I have a 16" 300BO but I do. LOL.