I've seen a couple of Rem 700's modified to use the 378 cases, they were set up as single shots. I never measured the bolt faces, but the rims looked very, very thin. Of course, that's just an opinion, so take it for what it's worth. I have a Sako TRG-S that I'm thinking of turning into a switch barrel rifle for the the 378 based cartridges (it's in 338 Lapua now). I've also used and had a couple of P14's set up for wildcats on these cases, and they work fine ( a lot of work, but they do the job). #1 's would be the easiest to do, and probably the cheapest. P14's/17's would be the cheapest to buy, but by the time you modify everything to work, you have a fair bit of money into them. I still like them for the big magmums tho'. - Dan