Yes you can put a break on a factory barrel but be forwarned because the thing about brakes is the noise they emit. Although your supposed to wear hearing protection while target shooting, you will need to wear hearing protection to shoot a muzzel brake equipped gun while hunting in my opionion. The noise level increases 2-3 times over a straight barrel and the noise is so bad it makes me feel like my ear drums are busted and bleeding. It really is that bad. The gun crack is so sharp it hurts for days.
I shot a Browning A-Bolt in 270 Win with the Boss Brake on it without hearing protection. The first and last muzzle brake gun I'll ever shoot without hearing protection.
By the way...The Browning Boss Muzzle Brake installed on factory A-Bolts was "Tunealbe" for accuracy. Just screw the brake a little amount either direction and it would help the accuracy of the rifle so they say. I have no idea if it does or not, I only shot the gun one time as it belonged to somebody else. I don't know if they even offer it anymore. I'm not a Browning type of guy.
To me, they aren't worth having for any type of hunting that requires you to hear the animal coming, which is just about all big game, but if you varmint hunt for groundhog or prairie dog then no problem since you don't need to hear your game coming, only a visual and then...