Yeah - huge - our own Ed Huble made an 3 1/2" .835 cal. with a M14 or P17(or is it the other way around? - is that big enough?

Appears the sky's the limit - however, a .5 Browning won't fit.

I've a friend locally, who uses Model 17 actions or P14's for all of his favourite hunting rifles. I just threaded up and chambered a .308" groove diameter barrel for him in .303 so he could use 220gr. Hornady's. His favourite hunting rifles are 8x68S Magnum and 6.5x68 Shuler, both on the P17 or is it M17?

Rear receiver bridge is usually ground flat. Bolt left as original, or changed as desired. Bottom metal flattened to remove step unless extra magazine capacity is desired.

Bit of work for a milling machine and drill press.