Not in a factory option. I remember researching this in late 2016 and someone was building a custom bolt rig. Lots of AR’s out there of course. I ended up with the 450BM in bolt config due to availability of brass, etc. It fit my needs for a 250 yd whitetail setup.
I cant remember what company was building raptors but i know there are options for custom route. Good luck with your search.
I was interested in both cartridges, but rand the numbers through a ballistic app and the .450 Bushmaster had less energy beyond 50 yards than a 150gr. .308.
I just ran .45 Raptor with a 240gr XTP vs a .338 Federal with a 200gr Ballistic Silvertip, and the .45 had a MPBR of 269 yards, dropped below 1,000ft-lbs just past 300 yards, and went subsonic around 450 yards. The .338 Federal had an MPBR of 319 yards, maintained 1,010ft-lbs at 625 yards, and didn't go subsonic until 975 yards.
As cool as those big bores seemed to me, they ended up just not making enough sense when there were easier to acquire, and cheaper, options that were superior. Not to say they don't have a place. They just don't in my hunting.
I am also looking into the 450 bushmaster and 45 raptor for hunting in Iowa this fall. There are some guys selling some 45 raptors on savage actions on ebay. But i am waiting for Christensen Arms to make some more 450 bushmasters. Either way it will be an improvement on the old slug gun.
I hunt in Iowa, and not to take away from the 45 raptor bolt gun (I was thinking down the similar path, I'm pretty sure McGowan makes prefits and Remage setups) but I decided on a 1975 Marlin 444. Doesn't exactly match the 45 raptor, but definitely outperforms the 450 bushmaster and is grandfathered in in Iowa. Mine holds 3/4 MOA out to 200 yards with Hornady Superformance ammo.