After some advanced diddling, it seems that adding another .050 to .100 inch of boolit room before it beats up against the rifling in my 6.8mm Remington SPC would be worth it. Research has stories of short leades and abrupt angles that the SPC II spec have addressed. Who the heck has a dimensional drawing for the SPC II? So far, all I've seen is the SAAMI SPC.
Chamber and neck are fine. Don't want to mess with the throat. But I want the rifling OUT a skosh. The AR folks have a neat AR SPC II reamer that has an aluminum body that fits in the upper receiver, fits in like the bolt, except there is a reamer fitted to it. Unfortunately, the Contender does not have enough upper receiver support to do that