WTK info on fitting the CSS Internal Receiver block
 

I am attempting to fit the CSS internal receiver block to my S12. I have cut off the tang on the rear trunion and have attempted to install the internal receiver block . However, when i attempt to mount the receiver block in the holes for the former original FCG, there is about a 1/16 gap between the rear of the receiver and the receiver block. Any one else have this problem? I am wondering if I have to egg out the holes in the receiver to make it fit flush? Any one have any thoughts on this?

You might have to egg the holes a little, 1/16" isn't much.
Is the gap on the bottom or is it a forward/backward type thing? If it's the bottom will it come back when you tighten the top screw?
Never messed with one so I'm guessing

this is common, at least on the 4 ive done. i did egg the holes just a bit. the screw heads will cover the holes so it will not look unsightly.

Fit varies a bit. On mine I had to egg the holes, but my brother's fit perfectly with no egging required.

that is what ended up doing; egging the holes that is. I tighted down the screws real tight with some red lock tight. Now i just need to decide what stock Iam going to place on it

I've got an app for that. 8^)