450 Bushmaster

Slappy White said:

Hi guys. I've been reloading for a few years but I just picked up a new rifle in 450 Bushmaster and I was just wondering if there was anything quirky or special about reloading for it. I've read a few things about being careful not to crimp too much because it headspaces off the case mouth. Is that really an issue? Thanks in advance for any info!

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It is in fact like loading a large straight wall pistol cartridge. Basically a giant 45 acp that takes pointy bullets. Other than not crimping too hard, there really isn't anything to it at all. With the Barnes 275 grs tsx it is an absolute devastator of hogs.

Like DocRock said, its like any other straight walled cartridge. I use Lee dies for the Bushmaster and am very happy with them, the only difference from my other dies is that they are not carbide so case lube is necessary.

Don't trim them if you can help it. Unlike a bottle neck cartridge 450 Bushmaster gets shorter with each firing not longer. Case head expansion that you fully can't get back with sizing causes this shortening. Your cartridges will probably get too short to headspace correctly before they split or otherwise fail. If you do need to trim to get them all the same length for crimping purposes do so while keeping them as long as possible. It a fun cartridge! Enjoy.


Left to Right: Barnes, 200gr XPB, Barnes 275gr TSX, Hornady 240gr XTP/MAG, Hornady 300gr XTP/MAG, Hornady, 225gr FTX, Hornady 250gr FTX, Remington 405gr SP (resized).

I've been contemplating a big bore AR and was on the fence between 458 socom and 450 bushmaster, but the bushmaster won out. It's use of pistol caliber bullets made sense for expansion thresholds and cost of projectiles. I think the 450 bushmaster is really becoming popular with hunters out east which hopefully will pique interest of some light for caliber rifle bullets for supers that expand for it.


@mcb
I assume you are going for subsonic with your 405gr SP's? What expansion do you get out of them at subsonic speeds?

BreechFace said:

I've been contemplating a big bore AR and was on the fence between 458 socom and 450 bushmaster, but the bushmaster won out. It's use of pistol caliber bullets made sense for expansion thresholds and cost of projectiles. I think the 450 bushmaster is really becoming popular with hunters out east which hopefully will pique interest of some light for caliber rifle bullets for supers that expand for it.


@mcb
I assume you are going for subsonic with your 405gr SP's? What expansion do you get out of them at subsonic speeds?

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Yes I the 405 gr bullets were loaded for subsonics. Loaded to 1050 fps from my 20 inch barrel. I don't have a 45 suppressor yet but using a friends SilencerCo Hybrid it was pretty quiet and cycled well. It would not cycle unsuppressed.

I've been kicking around the idea of a 450 BM......But those brass prices

Texas10mm said:

But those brass prices

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Are mitigated by the long service life of the straight wall cases.

Texas10mm said:

I've been kicking around the idea of a 450 BM......But those brass prices

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Eh...I just buy bulk Hornady 250gr FTX for $1/round (current crazy prices) and enjoy shooting to collect my brass. Sounds like a lot but with the life one gets before splitting necks on straight wall cases I can live with it.

mcb said:

Yes I the 405 gr bullets were loaded for subsonics. Loaded to 1050 fps from my 20 inch barrel. I don't have a 45 suppressor yet but using a friends SilencerCo Hybrid it was pretty quiet and cycled well. It would not cycle unsuppressed.

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What gas length is your barrel? Carbine, Midlength?

BreechFace said:

What gas length is your barrel? Carbine, Midlength?

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I will double check but IIRC it is a carbine length gas system.

ETA: yep double checked. It has a carbine length gas system. Started life as an upper receiver kits from Bushmaster. Probably a collector item... LOL.

How far is a 450 BM AR throwing the brass?

Texas10mm said:

How far is a 450 BM AR throwing the brass?

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Mine makes a neat little pile at about 3 o'clock, probably 6 feet away. Would vary with gas tuning, buffer weight, and spring force.

Thought about the 450 but went 50 Beowulf instead. Plenty of .45 cal bullet checkers out there so I went bigger for my AR.....lol

The .450 should serve you well.

.223, .300 BO, 7.62x39 and .50 Beowulf.

Texas10mm said:

How far is a 450 BM AR throwing the brass?

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Mine only throws it 10-12 feet away.

I live in Southern MI. I go to the rifle range just before Deer season when everybody is sighting in their .450 BM. Last year I scored 140 pieces of brass in one day.

mcb said:

View attachment 920131
Left to Right: Barnes, 200gr XPB, Barnes 275gr TSX, Hornady 240gr XTP/MAG, Hornady 300gr XTP/MAG, Hornady, 225gr FTX, Hornady 250gr FTX, Remington 405gr SP (resized).

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Been kicking around the ides for a while as well. I want something .45, sorry Beowulf. I keep thinking Socom for the heavier available bullets for a suppressor. But then the cost difference leads me back to the Bushmaster.

MBC, please, do tell about the resized 405s. What is to it? What is needed? Etc.? This might just be my answer? Best of both worlds?

Wyman

I picked up a 450 upper a few years ago, more as a novelty. Fun gun to shoot. So far, I have not loaded my own, although I have all the dies and supplies to do so. At the time, the only brass available was Hornady, and it was over $0.80 each as I recall. I could buy their 250 ftx loaded rounds for $1.20, so I bought a couple hundred and started saving the brass. Starline now has brass available for $0.60 which is nice (still could be a little cheaper, IMHO). I can use some of the same bullets that I use for my 460 which is an advantage.

JWF III said:

Been kicking around the ides for a while as well. I want something .45, sorry Beowulf. I keep thinking Socom for the heavier available bullets for a suppressor. But then the cost difference leads me back to the Bushmaster.

MBC, please, do tell about the resized 405s. What is to it? What is needed? Etc.? This might just be my answer? Best of both worlds?

Wyman

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I just picked up a pair of Lee sizing dies, a .454 and a .451 die. Used a good strong closed arch press (RCBS) and lot of sizing lub. Sized the .458 bullet down to .454 and then down to .451. I did get a bit of spring back and when I measured them I was getting between .4515 and .4522 on a micrometer. Seemed to work pretty good. I was able to shoot a 2.5 MOA 5-shot group with the load at 100 yards.

mcb said:

I just picked up a pair of Lee sizing dies, a .454 and a .451 die. Used a good strong closed arch press (RCBS) and lot of sizing lub. Sized the .458 bullet down to .454 and then down to .451. I did get a bit of spring back and when I measured them I was getting between .4515 and .4522 on a micrometer. Seemed to work pretty good. I was able to shoot a 2.5 MOA 5-shot group with the load at 100 yards.

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I’ve heard that when sizing jacketed bullets like that, the copper jacket springs back but the lead core doesn’t. Have you noticed any jacket separation problems?

Toprudder said:

I’ve heard that when sizing jacketed bullets like that, the copper jacket springs back but the lead core doesn’t. Have you noticed any jacket separation problems?

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I notice a very slight separation in some bullets at the interface between the front edge of the jacket and the lead exposed at the at the soft point. Never enough to have a core become lose. It that was probably as much from the core lengthening as the jacket spring back. Again very slight and did not cause any issues I noticed.

mcb said:

I just picked up a pair of Lee sizing dies, a .454 and a .451 die. Used a good strong closed arch press (RCBS) and lot of sizing lub. Sized the .458 bullet down to .454 and then down to .451. I did get a bit of spring back and when I measured them I was getting between .4515 and .4522 on a micrometer. Seemed to work pretty good. I was able to shoot a 2.5 MOA 5-shot group with the load at 100 yards.

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Thanks. I’ll have to give it a try. I knew it was possible with cast lead, but never even thought about it with jacketed.

Wyman