450 Bushmaster versus 458 SOCOM

[Suwannee Tim]

I have been shooting the 450 Bushmaster for over a year, 500 rounds of factory ammo and almost 1000 rounds of handloads. In that time I have used H110, W296, Lil Gun, IMR 4227 and AA 9 powders, every suitable powder for which data is available and I could obtain I have tried with 230 grain and 250 grain bullets. I have been plagued by hangfires, misfires, unburned powder in the barrel and lower, and jams caused by unburned powder in the chamber which prevented a live cartridge being loaded. I bought a Lee factory crimp die for 45-70 and cut it down to apply a so-called "Legendre crimp" i.e. a heavy crimp not on the case mouth but about 1/8 inch below the case mouth. With all that I have found one powder, IMR 4227 which works reasonably well if you don't mind a huge fireball, all the other powders work mediocre at best and very poorly at worst. I attribute this string of failures to the use of a small rifle primer. The small rifle primer even in magnum type is inadequate to ignite the 30 to 40 grains of powder used in this case. I have shot the very similar 454 Casull cartridge quite a lot, had the same problems with it and attribute the problems to the same cause, use of a small rifle primer. At least you can crimp the crap out of 454 without a hand made crimp die as the 454 headspaces on the rim not on the case mouth like the 450. Last week I got my long awaited 458 SOCOM kit from Wilson, put it together and loaded some ammo. I shot loads with Reloder 7, H110 and IMR 4198, all worked perfectly, no unburned powder, no hangfires, no misfires, no giant fireballs, no drama, they just worked. This I attribute to the use of the large pistol primer in 458 SOCOM, a highly appropriate choice given the relatively large volume of powder to be ignited and the relatively low operating pressure of the cartridge. Bottom line, if you want a big bore AR and plan to handload, save yourself a lot of grief, get a 458 SOCOM. Anybody want to buy a good used 450 Bushmaster upper? Brass? Dies? Ammo? Any suckers out there? No? Oh well.

P.S. The Hornady factory 250 grain 450 Bushmaster ammo I shot worked fine. I am not accustomed to nor enthusiastic about a cartridge with such a narrow window of good performance. Every cartridge I have any experience with, there are several to many powders and many loads that produce good to excellent results. Every cartridge except 450 Bushmaster and 454 Casull.

[Onyx Z]

I've always wondered what the difference between these two cartridges were. Now knowing, I would definitely opt for the large pistol primer in the 458 SOCOM over a small rifle in the 450 Bushmaster with that much powder. I typically go for the hottest primer unless they're just plinking loads, I want all that powder burning!

[Ttwwaack]

I'm surprised. Did you try Rem 7.5, or better yet what primers did you try. Did you contact Hornady and inquire about the ignition problem and see what pri er they are using in their 450 ammo. Are you getting well centered firing pin indents and good enough protrusion.

I've got a 50 BW and have not had a problems with CCI LP Mag and 38.5 gr Lil Gun and I run Win LR in the 500 S&W with 39gr of H110.

Thanks for the heads up on the shortfalls of the 450 BM.

ETA: I really liked the idea of the .451 BM becuase it is one less projo to keep in stock and you could get some pretty heavy pills designed for the Casual or go light for plinking.

[Suwannee Tim]

I used the CCI 400 small rifle standard primer to start and quickly abandoned it in favor of the 450 SR magnum which was a year ago the only SRM primer available. I see now that Tula makes a so-called SR magnum primer but I have 5,000 Tula LR magnum primers that behave like a US made LR standard primer, they damn sure don't act like a CCI 250 or a Federal 215 magnum primer. Given that experience I don't think I'm interested in Tula's SR so-called magnum primers. I did not try anything but the two versions of the CCI primer. Given the magnitude of the problem I doubt any other primer would make much difference. Too bad Federal doesn't make a SR version of the famed 215 magnum primer but I wonder if even that would solve the 450 BM problems. Something astonishing to me is that this 450 BM made it to market with a SR primer. I would have thought the problem as obvious to me, an amateur would have been obvious to the so-called experts at Hornady. I have to say I am not that impressed with Hornady's ballistics department. I have found inconsistencies in their data that I have not found in Speer, Sierra, Nosler, etc. Example, I wanted a load for 458 Lott with Reloder 7 as I had 20 pounds of the stuff deteriorating and I wanted to burn it in a hurry. Both Speer and Hornady list loads for Reloder 7 for 458 Win mag but not 458 Lott. To estimate a load I studied the relationship between the Win and Lott cartridges, same powder, same bullet. I found the Speer data very consistently showed the Lott using 9% to 11% more powder than the Win. The Hornady data was all over the place, from -2% to +17%, something like that from my very faulty memory. I was so surprised I did the same type of comparison between several other very similar cartridges and got the same result, the correlation from one to the other very consistent with Speer, very erratic with Hornady. I have found other loads in Hornady data that were just plain unsuitable, H414 in 300 Win mag for example. No, I have not called Hornady to see what they have to say, I will do that Monday. One reason I haven't called is much of my load development was for 230 grain pistol bullets which they do not support with data. I got the same pathologies with the 240 and 250 and there ain't much difference on a percentage basis. Long story short, I don't have a lot of confidence in Hornady data or their ballisticians.

[Suwannee Tim]

Another issue I found is with a suppressor. I have a Wilson Whisper suppressor I can use on either gun. The 450 BM with the suppressor is LOUD and I get an amazing jet of flame out of it, very visible even in broad daylight, more, much more visible even than the considerable flash from unsuppressed use. I suppose maybe the Wilson muzzle device less can jets the flash left and right out of the shooters view whereas with the can the flame shoots forward where it is in the shooters vision. I have only had the can for a month or so so my experience is somewhat limited. What I know for a fact though, same suppressor, same barrel length, a SOCOM shooting a 405 or 500 grain bullet is a damn sight quieter than a BM shooting a 230 or 250 grain bullet. A damn sight quieter. Of course there is a big difference in the velocities, 2000 fps + for the BM versus 1000, 1100, 1200 fps or so with the SOCOM. For that matter, the BM unsuppressed is a heck of a lot louder than the SOCOM in fact the BM sounds to me as loud as a big gun i.e. 375 H&H or 458 Lott. Another difference the recoil of the BM is a lot rougher than the SOCOM which is pretty gentle. The SOCOM is really a gentle push where the BM is a whack. The BM kicks hard enough it would intimidate many, maybe even most shooters. It don't bother me though. I ain't skeered of no gun!

[DarkTemplars]

Sounds like I've finally gotten some good luck to balance the gun thefts from a few years ago. I ordered my WC 458 upper at the end of Mar and got delivery notification last Thursday. I should have it on Monday.


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[Suwannee Tim]

I am eager to shoot mine some more. I'm making a rare Sunday morning range trip tomorrow. The 458 SOCOM won't fit in a standard Dillon powder die, you need a special oversize powder die and expander.

[tylojuky]

I am eager to shoot mine some more. I'm making a rare Sunday morning range trip tomorrow. The 458 SOCOM won't fit in a standard Dillon powder die, you need a special oversize powder die and expander.

Have you had a chance to get some time behind that 458 SOCOM?
I'm in the process of building one right now. Until this post, I haven't found anyone with any direct experience with the Whisper Suppressor on a 458s.
Please let us know how it performs. Is it "Hollywood Quiet" with subsonic loads - do you still need ear muffs - somewhere in between? How about with supersonic loads?
What loads are working good for you? ... I can keep typing questions but you get the idea - some of us out here are really interested in learning from your experience.

Thanks.

[1slow01Z71]

I haven't shot mine with subs yet but with supers it makes a huge difference but Im also running a 9.5" barrel.

I went with the bowers because its a much larger can and with how much powder the socom uses I just don't think a 6.5" can has the volume to take care of that and Im not a fan of the higher pitch titanium cans make along with the sparking. Ive got one ti can and that was enough. Ill deal with the couple extra ounces of weight.

[lattin1]

I had no idea the Bowers can was that big, good lord! Thinking about getting one for my 458 and .50 beowolf but I might be SBR'ing them after seeing that.