Big Game Rifle question

I'm trying to justify buying a Springfield M1A. Being able to hunt big game with it would help. Does anyone know if I can if I get 5rd mags, or is there something against detachable mags? Also a link to the hunting/gun regs would be nice, I must be having an internet brain fart cause I can't find them on the net anywhere right now. Thanks.

http://wildlife.state.co.us/RulesReg...es/BigGame.htm

http://www.44mag.com/prodinfo.asp?number=CM5

I know several who do hunt with the M1A, you will need to add a scope mount for a couple hundred unless you shoot the irons.