Which Mags to Get For 300 Blackout in AR-15

[Warren Sear]

Standard .223/5.56 magazines work, but not the greatest. I have been told there are magazines made especially for this purpose, but I can't find any. I just put some Magpul pmag M3 magazines in my car at Midway, but I want to find out from folks with experience that these will work better than standard magazine. Anyone with experience with this???

 

[usm1rifle]

I have not had a problem in either of my 300BO pistols with 20 round P-Mags or old 20 round GI aluminum mags. Just got 5 Lancers on black Friday and am going to test them Thursday. I'll try to remember to tell you how it goes...

Al

 

[jack the toad]

Sorry, not much help but in my limited experience, I've not had any issues with various metal or plastic in the BO.
Or for what it's worth, using metal in the .458 SOCOM.
This using standard 223/556 mags in both 20 and 30 round.

 

[ladder13]

I believe there may be an issue with the 220 gr feeding. I heard/read something about the design of the followers being changed on the 300BLK specific mags.
The mags are very hard to find currently, and I think only in 30 rounders.
My 300 is fine so far using the standard 20 rd Magpuls, with all weight bullets.

 

[4506517]

Check Mag Pul's website.

They make a specific 300 AAC magazine.

 

[LPD256]

I use Lancer mags specifically designed for 300 BLK. Although I can say I never had any problems with 223/556 Magpul mags. All the usual places like Brownells, Midway USA have them. Others as well.

 

[LPD256]

Lancer .300 Blackout. Snapped a photo

 

[billwill]

magpul 5.56 and don't worry. Thousands of rounds have gone down range out of those mags

 

[Bozz10mm]

I've never had a problem with 5.56 mags in my 300 BO, but I wanted some dedicated mags for it. I ordered a couple from Gun Mag Warehouse.

These are 30 round mags, but I bought 20 round Lancer mags that are OOS right now.

Magpul PMAG GEN M3 AR-15 .300 AAC Blackout 30-Round Magazine

 

[usm1rifle]

Used my new Lancers today and they worked with nary a hiccup.

 

[Warren Sear]

Thank you, gentlemen!

 

[CptCurl]

As people have noted, the .300BLK is made to work in an unaltered 5.56mm magazine. Let me add a caution.

With many loadings the .300BLK loaded round will actually chamber in a 5.56mm or .223 chamber. An internet search will turn up reports where this has happened accidentally, with the result being a blowup. If you have uppers in both chambers it is a good idea to use dedicated magazines so you won't make this mistake. For instance, you might paint a red stripe or other identification on the magazines you use in the .300BLK.

Always, safety first!

Curl