Caliber conversion in a Model 10 FCP - .308 -> .300 BLK

I require a bolt action platform for my suppressor and already have .300 BLK gear around. All ranges inside 200 yards and probably 7x glass.

I'm interested in converting a .308 Model 10 FCP to .300 BLK, using a barrel from Rhineland Arms (though I wish I could find one in 16"). The barrel swap seems straight forward... I think I understand the bolt head needs... But what about the magazine? Is the existing box mag expected to "just work" regardless of cal conversion?

http://www.savageshooters.com/showth...unter-LA-or-SA

Read down a few posts and you will find your answer.

So there's a block to keep the bolt from traveling back so far, and the magazine is the same mag, just with a block in it. Ooook! Thanks.