Just got a DD PDW, only put one mag through it…

[wylekyote]

Also, the adjustable gas key…basically, where the blowback tube curves downward toward the BCG, there’s just a tapped hole there and you can adjust a set screw to reduce the amount of gas passing through. Then you actually use a second set screw to lock the one doing the opening and closing into place. Interesting idea, but I think you’d just end up with a gassy rifle if you closed it off too much, and that the adjustable gas block wouldn’t have the same issue.

 

[Seadog]

Do you have an adjustable gas block?

I did not realize .300 B/O has their own magazines.

There are dedicated labeled mags to help people not mix up loaded mags. In some instances that shouldn’t happen 300 can chamber in 556 rifles. It shouldn’t chamber but I’ve heard it has.

 

[Seadog]

I’ve heard a lot of people run standard 5.56 pmags, but I like the idea of having visibly different mags for my 5.56 guns and my 300BO. PMAG makes a 300 BLK-specific mag, but there is a company called lancer that supposedly has really nice mags that are easily distinguishable from pmags.

I do not believe it has an adjustable gas block.

Buy more 556 mags and you could just run some tape on it. Pick a color. I’ve seen some instances were they actually charge more just because it’s labeled 300 instead of 556.

 

[Aries]

You can get something like these to put on the magazines, there are quite a few options as to color, etc. Just google magazine caliber bands for some choices.

Faxon Firearms Magazine Marker Bands - Caliber Identification

Faxon Firearms Magazine Marker Bands- Caliber Identification | Rifles, Pistols, Rifle barrels, AR-15 parts, Pistol Parts | faxonfirearms.com

faxonfirearms.com

 

[adamsredlines]

The blackout specific mags have different shaped feedlips to help with feeding of the fatter subsonic bullets. Supersonics will run fine in 5.56 magazines but with the subsonic being fatter at the end you can run into issues hence the specific mags for them.

 

[adamsredlines]

FWIW I use black pmags for 5.56, tan for supers (not blackout specific ones) and Lancers blackout specific mags for subs.

 

[wylekyote]

FWIW I use black pmags for 5.56, tan for supers (not blackout specific ones) and Lancers blackout specific mags for subs.

As soon as I get enough 300 BLK ammo to fill some more mags I may do this…I have like 30 something pmags

 

[SPDguns]

Use a pin gauge and measure the gas port in the barrel. Make a phone call to DD and verify the port size for your application. Eliminate all of the other problems to make 100% sure the port size is the problem. One you drill it out, you are past the point of no return and will have to get an adjustable gas block if you drill the port too big...