5.56 rounds working in .300 BLK mags?

[Cane55]

I’ve read that some .300 BLK rounds work better in magazines specifically made for .300 BLK, but does anyone know if 5.56 can work in .300 BLK specific magazines just as reliably as standard 5.56 magazines? Thank you

[WornOutGrunt]

I have never had an issue running 300 BO in standard 5.56 mags. The 12.5 and 16" BCM I had both ran a several hundred rounds fine with them, I think some of the issue was people using Subs ( I ran Supers) that were on the heavy end ( 220g) and the OAL was the issue.

I am a sample size of ONE.... so take that for what its worth

[joedirt199]

Only difference in 300 BO specific mags would be the front rib that keeps the bullets in line is shorter, protrudes less into the mag body, to compensate for the fatter .308 bullets. Some may have heavier springs than .223 versions.

[Clint]

This is a very poor idea.

Mistakenly firing a 300blk round in a 556 upper will blow it up.

Half the benefit of dedicated 300BLK mags is to help prevent mixups.

...does anyone know if 5.56 can work in .300 BLK specific magazines just as reliably as standard 5.56 magazines? Thank you

[PappyM3]

This is a very poor idea.

Mistakenly firing a 300blk round in a 556 upper will blow it up.

Half the benefit of dedicated 300BLK mags is to help prevent mixups.

I’m not sure I agree with that. 300blk mags look close enough to 5.56 mags that if you’re distracted enough to put a 300blk round in with 5.56 rounds, you’re just as likely to be distracted enough to not notice the mag is a 300blk mag.

I suppose it helps a little.

[Straight Shooter]

This is a very poor idea.

Mistakenly firing a 300blk round in a 556 upper will blow it up.

Half the benefit of dedicated 300BLK mags is to help prevent mixups.

I’m not sure I agree with that. 300blk mags look close enough to 5.56 mags that if you’re distracted enough to put a 300blk round in with 5.56 rounds, you’re just as likely to be distracted enough to not notice the mag is a 300blk mag.

I suppose it helps a little.

Damn. Some of yall would argue with a fencepost.

[PappyM3]

Damn. Some of yall would argue with a fencepost.

We shared differing opinions relevant to the thread. What’s the problem?

[Backfire]

This is a very poor idea.

Mistakenly firing a 300blk round in a 556 upper will blow it up.

Half the benefit of dedicated 300BLK mags is to help prevent mixups.

I got some Lancer purple mags for my 300BO, something distinctly different, or some tape around the bottom of the mag.
Especially if you go with friends things can get dicey and easily mixed up

[Cane55]

I apologize if I didn’t ask my question correctly. I just wanted to know if 5.56 rounds work in .300 BLK magazines, NOT if .300 BLK works in 5.56 magazines. For instance if only .300 BLK magazines were in stock for purchase and someone with only 5.56 ammo needed magazines.

[grizzman]

I thought the question was stated very clearly.

I don't have a .300 BLK, so I can't provide an answer.