u/RadixSorter

Hey everyone

I have the DDM4 300s 300 blackout upper (10.3" barrel) that I'm building into an ARP, intending to run subs primarily but also supers as well.

I'm considering either putting a Dead Air Sandman X, a Dead Air Nomad 30, or a OCL Polonium 30 on this build.

I know DD uppers have a reputation for being overgassed, which is why I'm curious if a low backpressure can (the Sandman X, in this case) would still be able to cycle subs or if going to a higher backpressure can is still required.

Hey everyone,

I'm putting together my first 300 blackout ARP (not first AR pattern firearm though) and I had some questions about this complete upper receiver.

I really like the idea of a 10.3" barrel and despite the price (which for DD is always very overpriced) this upper seems to be the best option. But, I was curious as to how it runs with subs and supers. Is a high backpressure can needed to cycle subs in this upper or can a low backpressure can be used and have it cycle? I have a SB Tactical HBPDW brace that I'm planning on using, but I can put a more standard SB Tactical Brace on instead if that would work better.