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450 Bushmaster - more info

3K views 27 replies 6 participants last post by  hcpookie 
#1 ·
Of all places Wikipedia. So take it at face value. :wink:

Brief summary of the info indicates the .450 Bushmaster is a modified .45 Professional developed by LeMag Firearms. The parent cartridge is 1.77", where the .450 Bushmaster is 1.70" to handle the Hornady ballistic-tip bullet. Both are apparently based on the .284 case, with a rebated rim, presumably for use with the AR bolt.

A quick glance at the Handloader's Manual of Cartridge Conversions indicates the .284 Winchester measures 1.775" from the base up to the bottleneck. Therefore, it appears that the conversion is as simple as cutting the .284 at the bottleneck, and you have a .45 Professional round. Trim it to 1.70" and you have .450 Bushmaster brass. I don't know if neck reaming is necessary but it probably is.

The base of the .284 Winchseter is .473". Yes, that's the same as a .30-06/.308 family round. Therefore, one would expect that -06 brass couls be converted to .450 Bushmaster by "simply" cutting to 1.70".

Things that make you go HRM.


I can't find anything on the "45 Professional" parent cartridge no on the LeMAG company. Every search gets hits for "L E MAG" articles.



Here are the source quotes:

http://en.wikipedia.org/wiki/.450_Bushmaster


The .450 Bushmaster (parent cartridge is the 45 Professional) rifle/cartridge conversion, was developed by Tim LeGendre of LeMAG FIREARMS LLC., and licensed to Bushmaster Firearms International LLC., for production and distribution. LeGendre still retains ownership. The 450 Bushmaster is designed to be used in the standard M-16/AR-15 platform, using standard magazines.

Bushmaster asked Hornady to produce the 45 Professional ammunition for this project, Hornady agreed. Hornady wanted the 45 Professional shortened, to accommodate their Venerable 250gr., Pointed, SST bullet. Hornady asked Bushmaster for the change (1.771" to the now standard 1.700"), Bushmaster asked LeGendre to sign off on that change, and he did. Bushmaster eventually wanted a name change and LeGendre agreed, to what has now become the popular 450 BUSHMASTER.

Based on a concept by Col. Jeff Cooper (Thumper), the goal was to provide guaranteed one-shot kills on Big Game animals at 250 yards, with a large bore semi-auto (44 cal or larger). Col. Cooper upon being presented with the early 45 Professional stated??this is Thumper Senior?I can now own an AR-15?. A 45 Pro was indeed built for Col. Cooper, by LeMAG, pretty good considering his disdain for the AR-15 in 5.56 NATO. Hornady, with its extreme expertise, busted the Cooper 250yd limit. The result is the 450 BUSHMASTER, a semi-auto rifle/cartridge combination that absolutely provides more than enough stopping power to adequately kill all Big Game in North America.

I came across only one other reference on a blog page, again take it at face value:


It has been called to my attention that when I referred to the "45 Professional" cartridge dreamed up by Tim LeGendre, I should have said that it was based on the 284 case, rather than the 280 case. The 284, with its rebated rim, permits a slightly larger powder capacity than the 280.
 
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#2 ·
I don't know if they ream either, but a 30.06 cut at 1.700 loaded with a 44 magnum bullet there is some taper. IIRC the brass at the mouth was .011 or so thick after opening them up.
 
#5 ·
30-06 brass will not work for the bushmaster. the reason is that 284 winchester is a REBATED ROUND FORM THE FACTORY. the case head above the rim is .500 very close to the size of a magnum round. the other thing that I have noticed about the bushmaster is that it also is a round that hornady uses SPECIAL powder not avaliable to the reloader. it offers better than 444 marlin in a smaller package but only with FACTORY $30-$40 ammo. If handloaded it will not be as good.
the 450 bushmaster is not much more than a rimless & rebated 458x1.5 (made from cut down 7mm brass or simular)! Im still pissed that I didnt build mine before it came out but oh well. it would be nice if reamers were avaliable for it same can be said for the 458 SOCOM. personaly i like the SOCOM better as it head spaces off the neck and not the case mouth and I think hase more case capacity.
 
#8 ·
Have you tried looking at muzzle loading bullets? I know Hornady has balistic tip bullets available in 44 and 45 for use in muzzle loaders but they're not cheap. Somehow when they put them in the muzzle loader box there's only room for 20 with sabots and they still run about $12 a box. The sabots would be useless to you though unless you have a muzzle loader. I'm still using their sabots and 44 lswchp. I've got no complaints from the deer so far.
 
#7 ·
HC it is one that I made up some dummy rounds for while looking at the 458x1.5 Barnes and 458x2 American that 1biggun had in his 458 ideas post. Just an extended 44 automag. The std automag and 1.5 Barnes were too short for the AK mag and the x2 American was too long. Its one of those projects that will I get around to someday.

ETA: I can get a pic of it if you want to see.
 
#9 ·
HC it is one that I made up some dummy rounds for while looking at the 458x1.5 Barnes and 458x2 American that 1biggun had in his 458 ideas post. Just an extended 44 automag. The std automag and 1.5 Barnes were too short for the AK mag and the x2 American was too long. Its one of those projects that will I get around to someday.

ETA: I can get a pic of it if you want to see.
Please do! I think it is great to see so many options that are out there for conversions of this size. My only hangup with the .44 size is the lack of ammunition and barrels for this particular application.
 
#10 ·
Ill have to check out the saboted rounds. I wasnt aware that they used a .430 dia bullet in the sabots. there are not a lot of bullets to chose from in .430 but the ones that are avaliable are pretty good. anything i hunt it going to die if it is shot any were close to were I aim with a 265 grain jacketed flat point out of a 444 marlin. infact it out performs the 45-70 in many areas. I would still love to see a .430 rifle style bullet with a point. the reason that there is not much to choose from is that most 44 cal rifles are lever action and there for are tube feed and that prevents pointed bullets. new blanks are avaliable for the same as other calibur new blanks. not a lot of surplus or take of barrels around however.
 
#11 ·
1.5 Barnes were too short for the AK mag
The 1.5" barnes BRASS is almost exactly the same length as the 7.62x39 BRASS. A 1.5x308 barnes is almost identical to the 7.62x39 in length. 1.5 is not the overall round length it is the length of the brass! it should fit into the AK mag quite nicely. 1.5x308 uses cutdown 308 win brass. 458x1.5 uses cut down Magnum brass (7mm mag, 300 win mag, 458 win mag ect).
 
#12 ·
1biggun, your right. I had a brain fart when posting. The 458x1.5 would fit the mag. It was the belt that I was wondering about. Feeding, stacking, etc. and if you turned off the belt then it would have to headspace off the mouth.

This was one of those "what if" things while waiting for some parts to show up. I was looking for ease of making brass and something that wasn't proprietary to a maker. I wouldn't want to spend 30 minutes per case to have the AK punt it to China or dent the crap out of it. Or send a barrel to someone to cut a chamber for X2-X3 times the cost of what a reamer would be and I could cut it myself. So, a 30.06 case cut below the shoulder, some 44 mag bullets that were on hand, and you get something like this.
Thumbnail:


The case would have to be fire formed as you can see from the pic that there is a dip below the seated bullet. The lead on top of it was smashed in the loading due to not having a 44mag seating die at the time. The case has not been crimped. On the 44automag they inside neck reamed to a depth of .590 which might be needed to help keep the bullet from moving under recoil...don't know. A Lee factory crimp might keep it in place or might need a canalure in the case....don't know. A RCBS 44mag neck sizer is too big to start in the case, so an expander cone is needed. Like I said, this was a "what if" thing and didn't mean to highjack the thread.
 
#13 ·
how long is the case in the center?? The 444 rimless that I am working on is exactly like that but longer aproximently 2.225(I havent decided on a OAL length yet). I should be able to use standard 444 marlin dies. the 44 automag must have a lot more taper if it needs to be inside reamed. I dont think the 444 rimles will need that as the 444 marlin dosent require it. I likely will have to aneal an fire form to straighten out the 30-06 brass.

the round you have pictured in the center would be a great build on a standard blank and maybe a modifed 223 mag. I like it a lot!! if you are going to fire form any way why not make it longer to fill a AK mag completly?? this will have to head space on the case mouth as well. A .41 cal version might be even better with better velocity and better case capacity to bullet weight plus it could be designed to head space on the shoulder. Better start a new thread for this.
 
#15 ·
Yet another link, this one in Spanish - thanks to US Dragunov who showed me this site. I'm not sure the information is 100% accurate because I don't have any brass to measure against:

.450 Bushmaster / MUNICION.ORG

Since the information is quoted (thanks Babelfish!) that it is cut-down .284 brass, the conversion may be that simple. I did not know this, but the .284 is dimensionally close to the .308 but has greater powder capacity. That *still* makes me think that a stretched .45 Winchester Magnum is going to be very close in performance to this round.



I was also reading on the Hornady site, and the definitely appear to have "pet" loads for their factory ammo. I'd guess they load it hot, because they seem to favor the right-hand side of the charts with their loads. I can't wait to see what their reloading recommendations will be.
 
#16 ·
That *still* makes me think that a stretched .45 Winchester Magnum is going to be very close in performance to this round.
I agree. it would also be about the same balisticaly as a 458x1.5. that is a good pic. It appears to be stepped down just past the base and even shows the reduction were the bullet is seated. reloading it will require very carefull case trimming due to head spacing off the case mouth.

I wonder how long before someone necks it down to .410 or .375 or .35.. A .375-450 BM would be a pretty good hunting round with better range.
 
#17 ·
I wonder how much difference a .284 and .308 cartridge that is cut to 1.7" has? Is the .308 that much thicker of brass? If it is an incrementally small amount, then IMO this would be satisfactory for the "intermediate" needs. I posted a few more links I came across in the "Intermediate" cartridge discussion thread:

http://www.gunco.net/forums/f244/45-50-caliber-intermediate-rounds-35115/

One of them talked about the .449 LWR and the fact that at 800 yards it loses all velocity. The Coast Guard was on that one, and the cartridge is a 2mm longer version of the .50 Beowulf (1.73" vs. 1.65" cartridge length).

The point is that the performance envelope carries this through the range of being able to disable "small water craft" engines at 200-yards, and no collateral damage after 800 yards. I would imagine these .45 sized Intermediates would be extremely close in performance. That level of performance is *perfect* for what I would see these being used for - home defense, property protection, anti-vehicular patrol use, etc.

BTW, you can buy the .499 LWR brass from the SSR Armory page:

7.62x51mm, 6.8, 5.56 Ammunition Custom Brass Cases

That has a 7.62x39 rebated base, so *NO* bolt mods would be necessary! Yes, that brass is about .50 per round. Therefore, if the use of .308 brass could be loaded with a significantly close amount of powder, say off by only a few grains, then IMO it would be cheaper in the long run to modify the x39 bolt to use .308, then live with the slightly lower velocity the smaller capacity cartridge would produce.

I have read that most people measure capacity by using an eye dropper and converting CC's to grains somehow.

I don't have any .284 brass to play with, which is the problem. Until I have some brass to play with, everything is a guess.
 
#18 ·
It will not take me long to mod a bolt to take the .470 rim. the 450 will have a fair amount more case capacity than a 308 0r 30 -06 . the .284 is .500 at the base (the same as a 45-70 or magnum brass). think of the 284 as a unbelted magnum made to shot in a 30-06 action. I thing the mag for the 44??? would be much eaiser to do as well.
 
#19 · (Edited)
#20 ·
The rim is the same as .308, but they have expanded the base to .500. I doubt you could fireform .308 to that size? That would be a .025" expansion at the base
Uh Im getting lost here as well.
I have no intention of trying to expand the base of a 308 round.
I have 41,44,45, 458 rounds on my brain Its getting hard to keep all the stuff that going on straight. LOL

I was just stating that the 284 case versus a 308 case cut to the same length that the 284 will hold considerably more powder than the 308.
 
#21 ·
Roger that. I don't know how to compute case capacity. Is there a formula of some sort? It is less than simple volume because you have to account for the webbing at the base. Is there a software program that does this?


Check this out - I was digging through my brass and realized I had some 300 Remington Ultra Magnum brass. This stuff is HUGE! I looked it up, and the exact measurements are .550 at the base, .534" rim, and 2.8" OAL with a .525" shoulder.

http://stevespages.com/jpg/cd300remingtonultramag.jpg

Now *THAT* would be a huge powder load for a .450, .44, or .50 sized Intermediates.
 
#22 ·
HC do you have a link to the home page of the site were you are getting all these nice pics of cartidge specs?????

that 300 rem mag might make a very nice .50x1.5 type round indeed. Hard part would be the large bolt face. maybe you could some how use a bolt and carrier from your 45-70 build? the rim of a 410 SG is .536 perhaps a siaga bolt could be used or possablly it could be rebated. Think it might be getting into the to much for a AK area again though.
 
#23 ·
Those are from Steve's Pages. Not sure how accurate they are, I'd have to cross-check them in my reloading manuals.

page8d


You are thinking *exactly* what I was! The PSL bolt face can be expanded out and VOILA! you have a bolt for the .50/RUM hybrid.

I about fell over when I saw the prices of a .50 cal barrel blank on Midway - $400!!!!!

Someone PLEASE tell me there is a cheaper .50 cal barrel somewhere?!?
 
#27 ·
WHOA!!
Hcpookie, I have to disagree with you on the 22lr being used for 5.45.

Dimensionally it may be close BUT often 22lr barrels are made of different/softer metals. I will try to find a spec sheet I have somewhere around here but it was different from the 4140 treated on the centerfire rounds.

May be a barrel maker could chime in here.
 
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