.223/5.56 Mag for 300 Blackout?

[SteveCNJ]

I put a 300 blackout upper on my AR15 lower. Are the .223/5.56 mags 100% feeding rounds using them for 300 blackout?

Thanks,
Steve

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[Dylabeatus]

I hesitate to say 100%, but anecdotally, I have shot all of my .300BLK with 5.56/.223 mags and have not had issues. Rough estimate would be 1k rounds with it.

 

[SteveCNJ]

I hesitate to say 100%, but anecdotally, I have shot all of my .300BLK with 5.56/.223 mags and have not had issues. Rough estimate would be 1k rounds with it.

Thank you!

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[E.Shell]

I only have about 500 reps, but 5.56 mags are all I've ever used too.

 

[Dunky]

I’ve used a bunch of 5.56 mags without issues Also have some magpul 300 blk specific p mags that work well.

 

[Matt5266]

I havnt had any issues either. But a do have a couple dedicated mags for self defense when I want to maximize feeding reliability

 

[KHNC]

I havnt had any issues either. But a do have a couple dedicated mags for self defense when I want to maximize feeding reliability

Its always good to be prepped for a solid gunfight in Idaho!

 

[WhisperPickle]

You probably won't have any issues with standard 5.56 mags feeding .300 blackout. In my opinion it's best practice to have specific mags used for the blackout, whether marked or dedicated mags, so that you don't accidentally pop one into your 5.56 and have a real bad time. I use Lancer blackout mags since they are completely different than any of my 5.56 mags.

 

[E.Shell]

You probably won't have any issues with standard 5.56 mags feeding .300 blackout. In my opinion it's best practice to have specific mags used for the blackout, whether marked or dedicated mags, so that you don't accidentally pop one into your 5.56 and have a real bad time. I use Lancer blackout mags since they are completely different than any of my 5.56 mags.

Great advice and a VERY real hazard. If one fires a .300BO round in a 5.56/.223 rifle, the result is typically catastrophic failure resulting in a ruined rifle and personal injury.

 

[Matt5266]

Its always good to be prepped for a solid gunfight in Idaho!

In my line of work theres more than a couple people that would like to put a bullet in me. I dont even mow the yard without a gun on me. Is what it is

 

[JRMiller]

Depends on the pills your shooting. Most anything under 150gr work ok in 5.56 mags, but over that, especially subs like 190-220gr you likely will have issues.
I have settled on the 20rd magpul .300 mags after trying many and they are pretty flawless ( I shoot almost exclusively subs around 200-220gr)
FWIW, it also depends on your feed ramps and if you've had them blended into the upper

 

[SteveCNJ]

Depends on the pills your shooting. Most anything under 150gr work ok in 5.56 mags, but over that, especially subs like 190-220gr you likely will have issues.
I have settled on the 20rd magpul .300 mags after trying many and they are pretty flawless ( I shoot almost exclusively subs around 200-220gr)
FWIW, it also depends on your feed ramps and if you've had them blended into the upper

Thanks. I do plan on shooting subs, have the ammo and just waiting for the can. No work done on the ramp.

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[MT762]

Standard GI mags work well. The magpul 556 mags never worked right for me. The magpul 300 BLK work great tho.