Since both are available as barrels for builds, uppers, and complete AR's I've been interested. There seem to be more varied bullet weights available for the Socom but the Bushmaster seems to be more generally used. I'm curious as to whether any of you have opinions on these two. I have no particular need for either but that doesn't mean I won't putter around with one.

Nosler has the .458 Socom throwing a 300gr bullet at 1950fps from a 16" barrel, while the best Hodgdon's has for the 450 bushmaster in the same wt bullet is 1975fps from a 24" barrel. Western powders give about a 200 fps edge to the Socom. Socom uses standard AR parts, including the mags. Only parts you need to change are the barrel and bolt.

I have a SOCOM, chose it for two reasons.

You do not have to have specialized magazines, and I already have a .45-70, so bullets and powder was in stock. RL-7 and IMR-4198 work great. As a matter of fact, I had it out today, I had just changed the barrel from a mid-weight 16" Tromix carbine gassed to a McGowen Precision 18" mid-gassed in a lightweight contour. Both barrels use SLR adjustable gas blocks

The throat on the McGowen is .060" shorter than the Tromix throat, and according to case capacity, the McGowen chamber is slightly tighter. These factors and the extra 2 inches of barrel gave me extra velocity, about 60 fps, with a Hornady 300 grain HP. I used RL-7 powder.

The .450 Bushmaster does seem to be an interesting cartridge, and if I had components for a .454 Casull (?), I would have probably gone with that.

My next quandary is......6.8 SPC or 6.5 Grendel......

.458 with new barrel:

I built the 450 Bushmaster because there's more choices of commercial ammo. It's just a more broadly accepted caliber at this point. More factory rifles, parts and accessories.

I'm just shooting whitetails with mine.

Either of your choices will get the job done though.

Dan

You will also have to mill the ejection port, lowering it about .050", but you are right, mods are very minimal.

Hornady and Winchester show 2200 fps for the 450 Bushmaster and a 250 grain bullet. I was thinking a 275 Barnes x would be good for elk too.

Our 20 Gauge slug loads are a 250 grain .452 bullet at 1800 fps and we use them to 200 yards.

Parts for the 450 seems more common than the 458 Socom and I believe the ammo is cheaper too.

I am sure both would be great. One of my friends in Alaska really likes his 458 Socom for black bears.

My question about the 450 Bushmaster is would a .875 GB barrel be better than a .750 GB barrel? Seems like a .750 GB barrel would be thin walled.

I just went to a .750" barrel from a .875".

I'm sure that at the pressure either round operates at, that is sufficient wall thickness.

The only downside I noted was that the rifle seems very slightly muzzle-light now, I prefer slight muzzle-heavy.

Thanks.

I have the Rock River 458 socom with LaRue scope mount and a Leupold Firedot scope. I went with the 458 as I have a few 45/70 rifles and quite a few bullet mold. I’m currently shooting the 300 grain Hornady jacketed HP. I used it for hunting whitetails here in Indiana before we could use rifle cartridges. Since we can use a centerfire rifle now the SOCOM is getting zero use.

450 BM is just fun and thumps the animals!

Up here in the Great Lakes Area 450 Bushmaster ammo is getting as common as 30-06 in stores....no special mags are need just a follower....your not going to find a 458 SOCOM bolt action.... there's Ruger, Mossberg, Savage making bolt guns....

Put the 450 Bushmaster in a bolt gun and handload....I can get with safe pressure under 58'000 psi 2950 fps with a Cutting Edge 160 gr. Raptor....in a AR-15 2740 fps....

My nephew took a small buck with his Ruger American .450 using factory Hornady. I was amazed at the size of the exit wound. The buck was DRT!

Hornady 450 Bushmaster 250gr. ammo is very accurate in every rifle I've seen it shot in....its not a very good bullet at all ranges....its like a varmint bullet at short range any meat with a shoulder shot is lost...getting close to 200 yards yards doesn't open very much. and should be put on the shoulder to help expansion...stretching it out to 300 yards shouldn't be done....