Regulated specifically for the RC4 Evolution slug, by me.

Bit of a story there, but if you follow the "RC4 Palla" link from that article, you'll get the gist of it.
Only problem was straightening the top rib before relaying it, the trauma had been fairly extreme and the rib ended up both bent and twisted, so it relayed a bit wobbly. Was supposed to be a temporary job pending a replacement top-rib, but as with a lot of my "projects" it just worked, so is yet to be redone!

I should add that my experiences with the RC4 slug made me a little uneasy viewing 260rem's pics of the GB slug in the Beretta Silver Hawk thread. I might respectfully suggest testing them on something akin to hide, flesh and bone before tackling anything that can bite back.