Okay so I did some math based on the sammi specs of the parent cases, maybe in out to lunch but, using the numbers of the 243 win and 6.5 prc, the prc is actually a slightly shorter case. If the neck size is the only measurement that changes, Ie, 6.5-6mm, than you can load a 115 berger with the boat tail junction at the neck/shoulder junction and it's "2.910, mag length in the rifle currently is 2.960", feed ramp is notched. 6 prc may be a very viable cartridge in a short action 700. I don't think it's worth messing with fire forming 243 for the extra juice.