Anyone have experience with a .300 BO DDM4 PDW suppressed? I picked up a complete upper and found it to be incredibly gassy with a suppressor. A massive amount of gas came out of the ejection port with each shot, and when reloading the mags, smoke came out of the top of the mag every time I pushed down the follower to load another round. Fortunately, the DD charging handle worked well and there was no gas to the face, so it’s more a visual effect than a real problem. Also, there was a definite increase in recoil shooting supers vs subs.

Configuration was the DDM4 PDW upper, Maxim Defense CQB stock with H1 buffer (which I believe is the same as on the full factory guns), and Griffin EZ brake. Suppressors were Griffin Explorr and Sig Hexium 762. Ammo was S&B subs and supers, and Magtech subs.

My reference is a Maxim Defense upper with an identical setup fired with the same ammo and the same Explorr can. The main difference is the barrel is 8.5” instead of 7”. Also, the gas block is farther back on the Maxim, about 3” from the muzzle vs. about 1” on the DD. Maybe this can all be explained if there is a larger gas port on the DD, but I’m not sure. Maybe it’s normal, or maybe I got a defective upper. What are your experiences with the DDM4 PDW?

I have one (factory original, not just the upper). I don’t have a suppressor so I’m using the OEM linear comp. I typically only run supers thru it, but I’ve had no issues in the stock config. I did initially change the buffer to the one that’s optimized for unsuppressed (I think that was the red one?)

Cheapest, easiest fix would be to bump up to the heaviest buffer you can get away with while still maintaining reliability with both subs and supers - H2, H3, H4 …

Otherwise there are bolt carriers “optimized” for suppressor use that delay the cycle to help with gas.