Here is how I built mine. It's easy to do if you have access to a lathe or Bridgeport milling machine:
500 Magnum custom compensator
S&W doesn’t sell a break with no holes for the 500, (like the 460 Magnum) so I modified a 460 into a 500.
This is how I did it:
Face the back of the compensator off .02 with a lathe. Maintain the shoulder outside step at .04 and the over all length of .905 long.
Bore the inside first shoulder step back .02. The inside diameter is .805 so don’t over cut this dimension as it aligns up on the front of the barrel.
Then bore the hole thru at least to .531 so that big slug can find it’s way out. I made mine a little bigger at .550 inch.
It locks up snug in my revolver and it looks factory but it’s not!