.450 Mosin Nagant?
Posted: Wed Jul 20, 2016 9:20 am
Years ago I bought a Mosin Nagant M44 with a sewer pipe barrel for $50 as a project rifle. I had wanted to rebarrel in .454 Casull since I have a revolver for that cartridge, it is a rimmed case, and it appeared that with some modification I could push-feed cartridges right out of the magazine. I got as far as acquiring a Douglas .452" barrel and a .454 Casull reamer. Eventually I got my 20" .450 Bushmaster upper and now I'm rethinking the .454 Casull in favor of a bolt action Bushmaster.
The case head diameter is smaller so I would have to deepen the cut for the extractor on the bolt head and maybe get a longer extractor spring. On the plus side, it would be much easier to rebarrel because I wouldn't have to index an extractor cut on the barrel stub. So long as the chamber fully supports the side wall of the cartridge, I could have a nice clearance gap between the end of the barrel stub and the bolt face. I may not even have to do anything about the clearance between the 450 Bushmaster case head and the lip on the bolt face. I believe that lip is just there to help keep the tapered cartridge case engaged to the extractor until the case is fully extracted and reaches the ejector. If extraction was a problem, adding a "C" shaped shim ring to the bolt face shouldn't be too hard. Some mods may be required for the existing ejector to work with the smaller case head. Use of the magazine may be possible with modification.
So if I have a .450 Bushmaster upper, why go to the trouble? Because I have the barrel blank and the action already, and it would be nice to have something I could use for heavy cast projectiles without fears of bunging up my gas system. Opinions welcome.
The case head diameter is smaller so I would have to deepen the cut for the extractor on the bolt head and maybe get a longer extractor spring. On the plus side, it would be much easier to rebarrel because I wouldn't have to index an extractor cut on the barrel stub. So long as the chamber fully supports the side wall of the cartridge, I could have a nice clearance gap between the end of the barrel stub and the bolt face. I may not even have to do anything about the clearance between the 450 Bushmaster case head and the lip on the bolt face. I believe that lip is just there to help keep the tapered cartridge case engaged to the extractor until the case is fully extracted and reaches the ejector. If extraction was a problem, adding a "C" shaped shim ring to the bolt face shouldn't be too hard. Some mods may be required for the existing ejector to work with the smaller case head. Use of the magazine may be possible with modification.
So if I have a .450 Bushmaster upper, why go to the trouble? Because I have the barrel blank and the action already, and it would be nice to have something I could use for heavy cast projectiles without fears of bunging up my gas system. Opinions welcome.