Quote:
Originally Posted by Colohunter
I have a 450 Bushmaster on order from BM that I should be getting next week. I have noticed there are a number of people shooting the 458 SOCOM subsonic. Has anyone tried the 450 subsonic? I know there are guys that are resizing .458 bullets to .452. For the most part I will be shooting lighter bullets supersonic, but I wouldn't mind having some sub loads.
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You certainly could shoot a 450 Bushmaster subsonic, but you'll have some problems.
If you shoot "normal" bullets jacketed bullets (300 grain or less) subsonic I think you'll have difficulty making it cycle the action, at least without modifying or moving the gas port. It might work with some unusual loads, but I can't think of what. To my knowledge there are no jacketed .451 or 452 low drag bullets available. Maybe you can swage a moderately low drag bullet from 458 to 452. I don't know of any commercial jacketed .452 bullets over 325 grains
If you could swage or resize heavier 458s (500 grain?) bullets to 451 then there would be a question of whether the 450 BMs 24" twist rate would stabilize it at subsonic velocity. I doubt it would . The standard RRA 458 SOCOM has a 14" twist and will stabilize fairly heavy bullets.
I'm not recommending the following but I like to experiment. If I owned a 450 Bushmaster AR-15 I might try loading it with TWO 300 grain Jacketed bullets stacked together. I'd robably choose Speer #4485 soft points with moly lube added to both shanks. Quickload Indicates that 14.3 grains of Hodgdon LilGun could toss the two bullets at about 950 FPS with 35000 psi chamber pressure at standard OAL.. (SAAMI max is 40,000psi). I'm not sure that would cycle the action but it's more likely than shooting one bullet subsonic. Being separate both bullets should stabilize but they might deform some. I wouldn't bet on great accuracy but I don't know. I AM NOT RECOMMENDING THIS LOAD. IT"S JUST A COMPUTER SIMULATION.
Duplex bullet loads aren't my idea:
http://cartridgecollectors.org/cmo/cmo08sepa.jpg
http://www.pridham.ca/43_Mauser_Two_Bullets.jpg