I'm looking to get a cheap barrel to use as a basis for a threaded barrel block, ie, wack the barrel off and leave a nominal 4" stub to for the scope base, and then bore it out and thread it to allow various barrels to be fit.

The question is, on the tapered and vent rib barrels, how long is the barrel full dia forward of the breach? Ie, do they allow a weaver scope base to be fit?