rossi is building a puma /92 in 480, I think for a bolt gun, look at the Mas 36, it has a large bolt dia, rear lugs , a shorter bolt travel, and a receiver/mag box big enough to build yourself a single column mag, you might look at the mag for a desert eagle 50 ae, maybe not long or wide enough, anoyjer thought is the mosin nagant, already has a big bolt head, and a single column mag with a feed interruptor, maybe with some spacing?, next is the 95 steyr st pull, not sure of absolute strength, but bolt face, charger clip might be about right, and the 8x57 conversions seem to take the ww2 52k psi ammo in stride, best , but hard to find would be a 44 mag cal Remmy 788, mag would have to be widened, bolt face reworked, one in 30-30 might also be a basis, I would also look at the savage/stevens 340, I have done one in 444m, you would have some metal working to do , but it might be a good bet, I have an action if you want to try