I had one a long time ago when they just came out, they were junk.
I heard they had gotten better, looked at a few on some mossberg shotguns, and decided to try one on my hornet, so far I really like it.
makes it a really nice compact unit, which is the only reason I have one.
they are much nicer than they used to be.
I WOULD NOT trust one on a 500 at all, In fact I would think of putting one on a shotgun either, other than a 410 that is.
Good luck, and be carefull
Dave