I've shot a lot of lead bullets through my 8 3/8" (not 8 3/4") with the fixed compensator without developing any problems. I do use the compensator intended for lead bullets on my 4" 500. I will say that, in my opinion, the porting on the removable compensators increases the perceived (and felt) muzzle blast by an inordinate amount. In fact, I'm considering machining a solid sided "compensator" for my 4" gun, as shooting higher speed/light bullet rounds (such as 350 grain/1850 fps +) is not altogether a pleasant task with the 4", due to the muzzle blast from the ports in the factory compensator (it is much nicer with 425 grain and up bullets at relatively sedate speeds, say 1200-1500 fps, not near the muzzle blast). I would go with the fixed compensator gun, especially given the ridiculous price differential between the two which you have available to you.