Why not hunt with his issue weapon? If he packs it and uses it hunting it could make him even more profficiant with it on the job. There is nothing like being completely familiar with your weapon. That's a good thing. If he's in good shape it won't hinder him at all.
A few years ago I ran into retired Marine Corps Major, Jim Land while antelope hunting here in Wyoming. For those who don't know who Major Land is, he aided in starting the sniper program and was one of Carlos Hathcock's sniper team captain's in Viet Nam.
He said he uses the same rifle for deer and elk that he was using on antelope. I asked to see what he was shooting and it didn't surprise me to see him pull out a Marine Corps issue M40A-1 with a Redfield issue scope. He said "It always worked for me in Viet Nam and I didn't see the need to change."
I can understand that.
We all got a good laugh when he said, "You know what the difference between shooting an antelope and shooting a VC is?"
"An antelope stands on four legs."
You won't hear that one on the History Channel.