HKParts 3-lug 1/2x28 adapter on a chopped 6.5" barrel with SilencerCo 3-lug mount on my Octane 45. It does wobble a tiny bit. No endcap strikes but I run the .45 endcap. No changes in accuracy or poi out to 75 yards. I really want to try a Griffin 3-lug mount but they aren't in stock anywhere.
I had my barrel chopped to 4.5" so I no longer use the 18x1 HK parts 3 lug adapter...
I now use a Griffin 1/2x28 3lug adapter with a Griffin Optimus setup in the short configuration for 3 lug. Smiodget of wobble but that is typical with 3 lug setups. Zero baffle strikes or end cap strikes in about 2,000rnds.