Took advantage of a recent sale and picked up a Griffin 11.5” upper with their gas pocket BCG and SN-ACH charging handle. Put it on an Aero M4E1 Pro lower and added the Griffin suppressor optimized buffer (SOB) and +15% blue buffer spring. My first 11.5” 5.56 DI experience many years ago with a suppressor was pretty bad. Very gassy with my Recce 5 suppressor, so much so that my “fix” was to swap to a PWS Mk111 long piston upper with an adjustable gas block to make it tolerable to shoot with a suppressor.

This new setup was a night and day difference. Tried with both my low backpressure Optimus 6 and conventional Explorr 224 Gen 2. Both were very pleasant to shoot from a gas perspective. No gas out of the ejection port with either, and only a faint puff felt from the charging handle area with the Explorr, but no eye stinging. I felt there was less gas than some of my 9mm direct blowback PCCs with a LBP can. The Optimus was definitely lower backpressure than the Explorr, and sounded a little better as the larger diameter helped overcome the higher flow. The down side is that being made of SS instead of lighter titanium, the larger Optimus was noticeably heavier than the Explorr. Definitely happy with the setup.