While I was at Keith’s machine shop, he showed me this clamp on compensator for a S&W K38 revolver. The do not seem to be that common although i have found some mention of it online.

The design is very basic looking. You just have one giant blast chamber that redirects some of the gasses upwards.

I am not sure how effective it is compared to a ported barrel design and I am not sure how well a simple slip on and clamped compensator would last.

Here is the compensator positioned at the end of my Heritage Rough rider just for illustrative purposes