Do we have any owners/users/operators (operating operationally ) of the BRN-4 uppers now that they’ve been available for a while?

I recall some anecdotal posts about machine marks being fairly prevalent which is annoying for the price point.  Brownells even notes that now on the product page.  Beyond that I haven’t seen much else.

I’ve got plenty of piston guns but I’ve stayed out of the piston AR realm.  (Though I’ve gotten close with the T91 uppers…)  Something about these specifically is intriguing, maybe the HK forbidden-fruit aspect?  The RAL-8000 accessories?  The various Euro militaries adopting them?  Dunno!  Part of me wants to try to build an M27 clone, another part of me thinks a random mashup 416 could be fun.

I’d love to see some feedback like how they are working, do they behave with suppressors, did Brownells/PWS hit the performance mark even if they are cosmetically dogs at times?

I have around 400rds through mine (chrome lined version). So far no malfunctions. I used hk recoil spring and buffer. I opted for the 10.4” upper and matched it with a standardized a1 lower. I most run it suppressed with a YHM T2. Great shooting as the recoil feels like a straight push back with no flip. Only piston I have to compare to is my Slr 106CR sbr.  The AK has less recoil and push as comparison. The Geissele trigger made a huge difference. Just a shooter for me and not going for a clone by any means. Accuracy been same as other Ars I have with normal plinking ammo.