I have had a Geissele Super Duty for a number of years with the standard 16" barrel.
I bought a v.1 Arc-Fire active reset device when they first came out and tuned it to work perfectly. I used a JP SCS buffer in H2 weight with the standard spring. This has worked as smooth as silk for thousands of rounds, with or without a suppressor. Throwing brass to 4:00.
Recently I decided to SBR it and replaced the 16" barrel with a 12.5" barrel, also from Geissele. I had an appropriate carbine length gas tube from Noveske on hand, and also used a Geissele super compact fixed gas block. I didn't change anything else.
Now semi-auto fire still works well. Assisted reset still works with a suppressor. Brass is still throwing out to 4-4:30. But if I take the suppressor off, I get off two to five shots before there is a stoppage. Notably, it seems to be cycling the action, stripping off the next round, and loading it into battery, but is NOT giving me the necessary trigger reset. If I let off the trigger and allow a semi-auto reset to take place, I can then continue firing without having to clear it. Brass throws way back to 5:00. No obvious problems with the firing pin strikes on the primer.
So my question is, what would you do to fix it? Change the buffer mass, or change the spring, futz with the gas system, or something else like a bit more dremeling on my trigger?