Bent a couple of blanks today and they were beautiful. They were blanks that we use (not Tapco) they have no holes and are blanked out a little wider. However the tapco flat is a little too short on the side and it is near impossible to bend the same way.
We have been using our own 4130 blanks and doing complete builds that way. Really easy, we made a drill template and just pop holes in the flat and go. Have about $2.00 in a receiver that way. We are thinking about making our template drill jig for sale as well as the UBJ. For now the tapco flats do not bend the top rails with the jig. Our blanks bend picture perfect.