I'm with Tech on this one, I would much rather buy a buildable core (last one I got was $35.00 at an auction with a C-6 attached) and have my machinist set tolerances to where I want them, not to where some 9 to 5 guy who doesn't know me from Adam thinks they should be set. Yeah, it might be more expensive to do it this way, but as in all things, ya get what ya pay for. I never will argue with someone who sells his stuff for less, he obviously knows what it's worth.