What do you think guys? I know it's not availible but would this be a decent set up for north american big game?

It is generally considered too much for the Contender and few barrel makers with chamber it in that frame. It's either back thrust and/or pressure but as a handloaded only round it would probably be ok. I'm guessing the relative performance would lie somewhere between the .30 Herret and the .30-30. It would make an execellent Encore round though as the action is much stronger. One issue with the 7.63x39 is the normal .308" bore vs .311" of the russian. You may have to choose between bullet selection for reloading or using some of the factory rounds sending pressure way up.

I had a 10 inch barrel made with a .308 bore. I don't shoot the .311 stuff through it. It's quite accurate with 125 grain Ballistic Tips and a bit more than a pinch of Reloder 7. Any of the folks making Contender barrels can fix you up.

I guess I'd have to ask why? If you plan on shooting cheap surplus ammo in it, you'll have to get a .311 bore to be safe with it. Using .311 bore takes most of the good bullets off the table for hunting use as most are .308 This round is rimless, not always the best for a contender. I'd recommend a 30-30, 30-30AI, or 30 Herrett or even the 30 or 308 bellm.

regards,
and good luck on whatever you choose,
Graycg

Performance wise, the 300/221 (AKA "300 Whisper") would also be quite similar to the 7.62X39, without some of the aforementioned drawbacks associated w/ the latter. my 12" 300/221 easily pushes the 125 gr NBT to 2250 fps and the 130 gr Hornady SSP to 2220 fps. Gary T.