Gas vs Piston SBR

I posted this in r/ar15 with little to no interaction. Wanted ti post here to see if I could hopefully get some more opinions.

I am currently building my go-to/do-all 11.5. I finished my lower and I’m now making my way to the upper. I try to do as much research as possible, but I’m very torn between going the piston route like a mk111, or go DI and build the upper from the ground up.

I know the piston systems are supposed to be softer shooting on average, but my build for the gas upper should do the same. My plan for the gas upper is a KAK down vent bcg, PRI gas buster, eztune gas tube, and a G$ barrel w/ gas block. From what I can tell, all of that (on paper) sounds like it would be a great and soft shooting rifle.

Some things to note: I have an a5 buffer system with h2 and the green Springo spring, and this gun will only be suppressed (likely with a polonium or another non-lbp can.)

My questions to you guys: Is there anyone who has experience with the same type of DI setup compared to a piston system like the mk111? Which would be softer shooting? Pros and cons of each direction? General recommendations?

Posted Feb 19, 2026, 10:09 PM UTC

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