450 Bushmaster vs. 458 Socom

450 Bushmaster has ~60.0gr of H2O capacity and an operating pressure of 38,500 psi
458 SOCOM has ~61.6gr of H2O capacity and an operating pressure of 35,000 psi

Not really enough difference to make much difference.

458 SOCOM has a better selection of 400 gr and heavier bullets if you are not into resizing bullets. That said I have resize some 405gr .458 bullets for a subsonic 450BM load I worked up that worked pretty well.

The myth that there are few .452 diameter bullets designed for 450 Bushmaster velocities may have been true in the past but that myth needs to die now. It is simply not true anymore. There is a larger and growing number of .452 diameter bullets designed for 450 Bushmaster velocities. Barnes, Remington, Hornady, Lehigh, Maker, etc all make 450 BM specific bullets. In addition any bullet that works well in 454 Casull or 460 S&W are prime candidates for 450 BM. There are many good bullets in the 200gr - 350gr range that work very well in 450 Bushmaster. Not to mention you can load cheap plinking ammo with your favorite 45 ACP FMJ bullet.

I agree the “uses cheap 45 ACP bullets” doesn’t pan out very well. There are some good choices for the BM though, just doesn’t make it any cheaper to shoot than the 458. If you cast and can get a mold you want, I don’t think it matters either way.



I probably grab the 458 more often because I can use the same Colt 20 round .223 mags I like using for everything else. With my 450’s I have to add a follower I 3D printed on top.
https://www.thingiverse.com/thing:2933498

The 450 is a straight wall, so it's g2g for whitetail in some states and since it's .452 cal it can be reloaded with plentiful inexpensive 45acp style 230gr fmj's.

Other than that, they're pretty similar.

.450BM is legal for Deer in more states, but that is changing.

Not a lot of difference in the two really. For those of us with straight walled cartridge rules though one is legal to hunt with while the other is not.

-Jeff

jmorris said:

I agree the “uses cheap 45 ACP bullets” doesn’t pan out very well. There are some good choices for the BM though, just doesn’t make it any cheaper to shoot than the 458. If you cast and can get a mold you want, I don’t think it matters either way.

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I probably grab the 458 more often because I can use the same Colt 20 round .223 mags I like using for everything else. With my 450’s I have to add a follower I 3D printed on top.
https://www.thingiverse.com/thing:2933498

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230gr FMJ with just enough Lil'gun to get reliably cycling does OK for cheap plinking in my 450 BM. They are not as accurate as other bullets but they do make cheap(er) plinking ammo and at those velocities they still make the milk jugs full of water do fun things.

I found a follower from calegalmags that I dropped into a few straight 20rd magazines and they work great and don't cost a round of capacity the center feed followers that sit on the 223 follower can cost you. I have several very reliable 7rd 450 Bushmaster magazine as a result. That said its pretty easy to get 10+ rd magazine for 458 SOCOM that is not achievable with 450 Bushmaster. If capacity is critical 458 SOCOM has an advantage.

I find the SOCOM has more options for heavier than 300 grain bullets if that's your jam. I probably shoot my .450 BM more because my shooting partner reloads the BM for us. It's a nice step up from the .350 Legend I carry during deer season with the possibility of both hogs and deer. When we are just going for hogs I take the BM. I probably should shoot the SOCOM and the .50 Beowulf more than I do. I would recommend any of the three if you need a thumper.

When 450bm came out there weren't a lot of decent rifle bullets in .452 diameter, whereas there were in .458. that has changed and there isn't a lot of use case difference between them except for the straight wall hunting states. I went 458 socom because I like a shoulder on a semi auto case, and I don't have a straight wall restriction for hunting.

Last that I checked, 458 SOCOM wasn’t SAAMI spec’ed. That may matter to some.

Are many 458 bullets designed to perform properly at the Socoms velocities?

earlthegoat2 said:

Are many 458 bullets designed to perform properly at the Socoms velocities?

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Think about the huge range of velocities and popularity that 45-70 is loaded to from loads replicating the old black powder cartridges (both with real black powder and modern propellants) to today's modern high pressure loads for the like of the Marlin 1895 and similar. There are plenty of bullets sized .458 that will work well at 458 SOCOM velocities. There are also makers making bullets specifically for 458 SOCOM and doing so in numbers on par with those making bullets for 450 Bushmaster. Neither cartridge is without a decent variety of good bullets to choose from.

Here you go.

http://www.teppojutsu.com/458faq.html

If you live in a straightwall only state, AND intend to hunt it, then the choice is obvious.

Otherwise, it’s really a horse apiece. There are likely just as many .452” bullets well suited to the 450B these days than there are .458” bullets well suited for the low impact velocities of the 458S. A lot has changed in the last decade for the .452” rifle bullet market. I’ve built a handfuls of each for customers, actually ended up with a 458S SBR upper a couple years ago on an abandoned customer project. If it wasn’t a 10.5” barrel, I probably would have simply resold it.

450 was my choice as a cheap beater hunter/camping rifle.

Performance kinda similar
450 rifle cheaper to buy
450 ammo cheaper to buy
450 ammo easier to find

I’m not sure how I want to build my third AR but both cartridges are possibles. I already have a Marlin in 375 Winchester and I’m about to pay off my handi rifle in 4570 so I have some straight wall cartridges for if I go to a state that requires them. I always thought the socom was interesting.

Blkhrt13 said:

I’m not sure how I want to build my third AR but both cartridges are possibles. I already have a Marlin in 375 Winchester and I’m about to pay off my handi rifle in 4570 so I have some straight wall cartridges for if I go to a state that requires them. I always thought the socom was interesting.

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Socom is very fun, but all ar big bores are fun.

earlthegoat2 said:

Are many 458 bullets designed to perform properly at the Socoms velocities?

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All the ones I like in 45-70 work just fine. The fact I already was well stocked on suitable projectiles, certainly swayed my choice.

I’ve pushed 405’s out of a 458 16” AR @ 1680fps, most people think they work great out of 45-70’s @ 1300. I’ve killed a lot of hogs with them at <1100 fps.

I don’t think I would own any of them if I didn’t reload though.

Blkhrt13 said:

I’m not sure how I want to build my third AR but both cartridges are possibles. I already have a Marlin in 375 Winchester and I’m about to pay off my handi rifle in 4570 so I have some straight wall cartridges for if I go to a state that requires them. I always thought the socom was interesting.

Click to expand...

+1... and once I built mine and worked up a load... I'm glad I made the jump... And I like a ctg to headspace on the shoulder...probably not better or worse... Just what I like. I once had a 450BM... Traded for cash to get my 458.