300 blackout magazines...

[ARMERICA]

I'm building a 300BO, it isn't done to test fire so I don't know that I actually have a problem here but I did load 2 30 round pmags with 300 rounds and they just feed out (by hand) kind of mushy. .223 or 5.56 slide out with a noticeably positive resistance and a sense of some force being exerted by the mag spring.

All that to ask if there are any 300 shooters out there that can tell me of they are having any issued with pmags loaded with 300BO, or have issues with 300BO and composite mags in general.
If so, are USGI/metal mags providing a distinct reliability with 300BO ammunition?

Thanks for any 1st hand knowledge you can provide.

 

[Klunatic]

.223 and 300blk are the same case essentially, can't imagine why they would feed differently out of the same mag. Unless they are subsonic very long rounds and they don't hang up in the mag they should feed fine.

 

[outrider58]

It's been said that some non-metallic mags have trouble feeding. Any mag, if not properly kept in spec will fail at the worst time. I prefer USGI mags. They are easy to repair and upgrade.

 

[ironpony]

I doubt I have as much experience as Klunatic and Outrider but I can see what you may be talking about, the area of contact between two 300 cases and two 223 cases is definitely less. so, my guess is (well my experience is) that when this stack of rounds balanced in a mag with their area of contact less than that of 223 rnds they can be less "supported". Similar to stacking water bottles, if the water bottles were long neck bottles ... a little less support. They should be fine. Get that thing built! there's plenty of help here. Wow, look at me, I'm swithcing back to my usual brand of coffee.

 

[omegared24]

I have no issues with my pmags or hexmags. Both work fine.

 

[Fox123]

Pmags have 2 ridges inside that the .223 case shoulder rides on. When you load 300BLK that ridge now runs on the bullet ogive. Depending on how deep you have seated the bullet and the profile will determine how well it feeds with pmags. If not seated deep enough the ridge will push the nose of the bullets towards the center of the mag.

For my plinking 147gr m80 bullets I seat them based on the mag so when loaded the ogive sits right on this ridge the same way a .223 shoulder would. (Sorry don't remember the COAL)

 

[Klunatic]

If you are reloading 300blk you have to be very careful with COAL. It is possible to make the COAL long enough that the ogive will make contact with lands of the rifling. This cam cause a dangerous spine in pressure. Either keep tho COAL within SAMMI spec or get a Hornady LNL measuring tool.

 

[outrider58]

If you are reloading 300blk you have to be very careful with COAL. It is possible to make the COAL long enough that the ogive will make contact with lands of the rifling. This cam cause a dangerous spine in pressure. Either keep tho COAL within SAMMI spec or get a Hornady LNL measuring tool.

Or smoke smudge a dummy round to check. The only 300 round I load that long are subs.

 

[Fox123]

Visit 300blktalk there are several posts regarding pmags and bullet profile.

 

[ARMERICA]

.223 and 300blk are the same case essentially, can't imagine why they would feed differently out of the same mag. Unless they are subsonic very long rounds and they don't hang up in the mag they should feed fine.

The 300 rounds I loaded the mags with are subs.

 

[ARMERICA]

Visit 300blktalk there are several posts regarding pmags and bullet profile.

Thank you for the lead

 

[ARMERICA]

I doubt I have as much experience as Klunatic and Outrider but I can see what you may be talking about, the area of contact between two 300 cases and two 223 cases is definitely less. so, my guess is (well my experience is) that when this stack of rounds balanced in a mag with their area of contact less than that of 223 rnds they can be less "supported". Similar to stacking water bottles, if the water bottles were long neck bottles ... a little less support. They should be fine. Get that thing built! there's plenty of help here. Wow, look at me, I'm swithcing back to my usual brand of coffee.

I'm working on it, believe you me. I'm really excited about this build. It will be the highest quality rifle I will have put together to date. That said, I don't want to cut any corners so the parts costs on this build are higher and I need to pace myself. Clandestine has been helping me with all my builds which point blank - none of them would have happened if it weren't for his input. He's been quite the mentor. He's been walking along side me on this one.

 

[Fox123]

Thank you for the lead

Your welcome, when on there pop in search function "pmag ogive" you will find many posts talking about the rib inside the pmag pushing the bullets towards the center and causing feeding problem on longer cartridges.

 

[DaemonAssassin]

I will run any mag I can get my hands on. I use Lancer 20rnd, PMAG Gen 3 30rnd, USGI aluminum 30rnd. Other than issues when you load only 3 rounds in the mag, I've never had a problem. If you want to link up sometime, and check out one of the Lancer 20rnd mags I have, you are welcome to do so.

 

[DaemonAssassin]

I'm working on it, believe you me. I'm really excited about this build. It will be the highest quality rifle I will have put together to date. That said, I don't want to cut any corners so the parts costs on this build are higher and I need to pace myself. Clandestine has been helping me with all my builds which point blank - none of them would have happened if it weren't for his input. He's been quite the mentor. He's been walking along side me on this one.

You will find no better mentor than Chad. He has mentored/taught many of us on here in the ways of the AR.

 

[ARMERICA]

Your welcome, when on there pop in search function "pmag ogive" you will find many posts talking about the rib inside the pmag pushing the bullets towards the center and causing feeding problem on longer cartridges.

Perfect. Will do, thank you!

 

[ARMERICA]

You will find no better mentor than Chad. He has mentored/taught many of us on here in the ways of the AR.

Yeah, he's a bit of Yoda that guy.

 

[DaemonAssassin]

Yeah, he's a bit of Yoda that guy.

Yoda and Obi Wan combined is a more accurate description.

 

[sailskidrive]

Yoda and Obi Wan combined is a more accurate description.

I was thinking more of Yoda and Freddy Mercury...



Has anyone tried the new Daniel Defense 32 round magazines? They're carbon fiber reinforced polymer.

 

[ARMERICA]

I was thinking more of Yoda and Freddy Mercury...



Has anyone tried the new Daniel Defense 32 round magazines? They're carbon fiber reinforced polymer.

HA! Perfect!