AR15.Com Archives
 .440 CorBon
FB41  [Member]
9/22/2004 12:27:49 PM
I own a .50 Beowulf and have access to a .458 SOCOM (and will soon have my very own to love and hold).

What I'm thinking of now is a mid-range caliber and I'm leaning towards the .440 CorBon from Tromix or something along that line. Something in a .41 caliber would be good as well.

Any helpful advise is greatly appreciated.
SHIVAN  [Team Member]
9/22/2004 1:44:25 PM
The 440 Corbon is a snappy little round when shot from a 16" AR barrel, I believe it's in the 2200fps or 2400fps range.

The BC of the pistol projectile sucks, but it is good to at least 150-200yds. Since Tromix uses a "match" quality barrel blank the little carbines are VERY accurate. Before I liquidated my 440 Corbon upper I grouped 4 shots in a one hole group at 100yds. {i.e. 4 shots all touching, looks like one big weird shaped hole}.

YMMV.......

I would get one again if I could find one on the cheap.......but they are worth EVERY penny of the NEW price.
FB41  [Member]
9/22/2004 2:17:17 PM
Thanks, Shivan... the cartridge sounds like it would be ideal here in the thick woods and swamps of FL. Do you know of anyone making a .41 caliber upper?
SHIVAN  [Team Member]
9/22/2004 2:20:38 PM

Originally Posted By FB41:
Do you know of anyone making a .41 caliber upper?



No, but I'll bet it would be difficult to make the mags work with the .41....the 50AE and 440 Corbon use USGI mags with polymer spacers and a special follower, and they single stack.....filling the mag from side to side. I think the .41 would be too narrow and would require a special mag setup, outside USGI shells.....or even worse bent up feedlips.

FB41  [Member]
9/23/2004 9:20:23 AM
Huh! Never thought of that! I'm gonna play around with necking down a .50B and see if I can get it to .41... just for grins.
TonyRumore  [Member]
9/23/2004 6:35:53 PM
The 440 is really a sleeper in the big bores. It is by far the fastest of the big bores, launching 180gr bullets at nearly 2400fps. 240's will do 2050fps and 300's will do 1800fps. It also has substantially less recoil than any of the others, allowing much faster follow up shots. With about the same knockdown power as a .454 Casull handgun, you have plenty of punch to drop anything in North America. Only about eight have ever been sold. If you purchase a complete rifle, I can engrave "440 CorBon" on the lower receiver if you like.



TSH77769  [Member]
9/24/2004 6:08:30 AM
What happens if you neck the .502 Thunder Sabre down to .44?

TSH77769
444slayer  [Member]
9/25/2004 5:34:56 PM
Funny you should mention that. I made a dummy round from the 50BEO, just playing around ahwile back. I wonder how close this coould be loaded to 444marlin velocities?
SHIVAN  [Team Member]
9/25/2004 5:58:38 PM

Originally Posted By 444slayer:
Funny you should mention that. I made a dummy round from the 50BEO, just playing around ahwile back. I wonder how close this coould be loaded to 444marlin velocities?
home.alltel.net/fdombek/44Thermopylae.JPG



Easily.......it's called the 458 SOCOM and can get there pretty simply.
444slayer  [Member]
9/25/2004 6:44:47 PM
Well,ok, but that is 45 caliber.........

What is the parent case/rim size of the 458SOCOM (50 Beo?), and what does SOCOM stand for, anyway?
SHIVAN  [Team Member]
9/25/2004 8:00:55 PM

Originally Posted By 444slayer:
Well,ok, but that is 45 caliber.........

What is the parent case/rim size of the 458SOCOM (50 Beo?), and what does SOCOM stand for, anyway?



Parent case of the 458 SOCOM is a lengthened 50AE. I have no idea the parent of the Beowulf.

SOCOM = Special Operations COMmand. It was the experiences of a SOCOM soldier that inspired Teppojutsu to develop the round.

444slayer  [Member]
9/25/2004 8:09:23 PM
Thank you, sir. I was asking if the parent of the 458 was the 50 Beo. I think 50 BEO is a new case.
SHIVAN  [Team Member]
9/25/2004 8:15:42 PM

Originally Posted By 444slayer:
Thank you, sir. I was asking if the parent of the 458 was the 50 Beo. I think 50 BEO is a new case.



The 50 Beowulf is it's own beast. It uses a 7.62x39 rim dimension. The 499LW, 50 Beo and 458 SOCOM are all kissing cousins. hence my comment on the 44 Thermo....

Kaliburz  [Team Member]
9/25/2004 8:26:59 PM

Originally Posted By 444slayer:
Funny you should mention that. I made a dummy round from the 50BEO, just playing around ahwile back. I wonder how close this coould be loaded to 444marlin velocities?
home.alltel.net/fdombek/44Thermopylae.JPG




Nice looking "dummy round". When I first saw the 50BEO, I too wondered if it could be necked down to 44 cal (.429") like the 440 Corbon.

I think what you would be proposing is a custom made set up. Quite easy to do in reality. As you have a dummy round, all you need to do is send it to a reamer maker to make the reamer to chamber such a beast and the dies to form and reload....

Wild catting...... or did someone make something like that???????


I have a 440 Corbon upper..... though I'm a cheap azz and it is sitting unfired..... too cheap to order ammo....
444slayer  [Member]
9/25/2004 8:40:04 PM
Even if you reload, the dies are the kicker. But once you pay for them, you are home free. Brass is easily formed from the Starline 50AE brass with the sizing die from the 440 set, though I prefer to use a die I shortened to get the shoulder pushed backa little further on the first firing.

I don't have a 440 upper, but I have a Desert Eagle in 440, and in fact I have the reamers, and have converted 4 44 Magnum Desert Eagle barrels and 2 LAR Grizzly barrels to 440 Corbon.

I wouln't be able to shoot 440, 500 S&W, and 50 Beowulf if I didn't reload.
kc3  [Member]
9/25/2004 8:49:28 PM
What's the recoil like on a .440 AR?
SHIVAN  [Team Member]
9/25/2004 8:52:39 PM

Originally Posted By kc3:
What's the recoil like on a .440 AR?



Kind of like a 240gr .308.....
Kaliburz  [Team Member]
9/25/2004 9:30:22 PM

Originally Posted By 444slayer:
Even if you reload, the dies are the kicker. But once you pay for them, you are home free. Brass is easily formed from the Starline 50AE brass with the sizing die from the 440 set, though I prefer to use a die I shortened to get the shoulder pushed backa little further on the first firing.

I don't have a 440 upper, but I have a Desert Eagle in 440, and in fact I have the reamers, and have converted 4 44 Magnum Desert Eagle barrels and 2 LAR Grizzly barrels to 440 Corbon.

I wouln't be able to shoot 440, 500 S&W, and 50 Beowulf if I didn't reload.
home.alltel.net/fdombek/440-2X800.JPG



Yup, I reload.... I while back, I priced a set of reloading and form dies from CD4H(????), all treated w/ that stuff so I wouldn't need lube. Quoted was about $250.00..... Haven't gotten any since I end up finding different things to spend my money on! (The AR pistol build was one of the projects....)

Oh, about your hypotheical round..... first of all, I'd need to find some reloading info for 50BOE and reloading for the 444 Marlin. Then see if any powder is "similar" and one could guestimate from there....

Your dummy round has gotten the gears in my head thinking..... that is not a good thing....
444slayer  [Member]
9/25/2004 10:14:22 PM
Midway has a set of RCBS dies in stock right now:

440 dies at Midway

I paid full price for my first set, and then lucked out and scarfed a brand new set from Gary Reeder, of all people, on Ebay, for $50!!

I have bought a few things from CH4D. My 50 BMG dies are very good quality, but everything else I have gotten from them has been pretty rough. I am hesitant to buy from them anymore.
TSH77769  [Member]
9/26/2004 12:25:19 AM
Well, Tromix has an M1 carbine that they converted to .502 Thunder Sabre. Why not an M1 Carbine in .44 Thermopalye?

TSH77769@hotmail.com
444slayer  [Member]
9/26/2004 12:41:46 AM
What's a .502 TS made from?

Nevermind, I just found this:

"Tony Rumore of Tromix is trying to tackle the former problem with the .502 Thunder Sabre wildcat. Designed by Robyn Church of Cloud Mountain Armory, the .502 Thunder Sabre is simply a .50 Action Express case with the rim rebated even further to mimic the 7.62x39mm. Rumore is currently testing his prototype, a converted Universal carbine, and is not yet ready to introduce the conversion commercially."

The easiest way to make an AR in 44 Thermopylae would be to take an extra barrel in 44 caliber and ream it out to 44 Thermopylae and stick it on a 50 Beouwulf. That was my plan, I just have never gotten around to it. It's alot of money for reamers, just so I can say I made my own wildcat, that is not any better than 458 Socom. (or, even as good?) But I would still like to do it just for kicks. The reamer cost would be the only large expense, as I can make my own dies.
TonyRumore  [Member]
9/28/2004 7:19:54 AM
Manson will make you a custom chamber reamer for about $150. I believe a set of dies from CH4D would run about the same. It's really no big deal to shoot your own wildcat, other the initial cost of tooling. The guys over on www.saubier.com are doing it all the time with the sub-cals.

I am buiding a one-off suppressed upper in .221LN for a guy right now.





444slayer  [Member]
9/28/2004 7:32:05 AM
Thanks, I was hoping you would weigh in on this.
Kaliburz  [Team Member]
9/28/2004 3:25:24 PM

Originally Posted By TonyRumore:
Manson will make you a custom chamber reamer for about $150. I believe a set of dies from CH4D would run about the same. It's really no big deal to shoot your own wildcat, other the initial cost of tooling. The guys over on www.saubier.com are doing it all the time with the sub-cals.

I am buiding a one-off suppressed upper in .221LN for a guy right now.









Originally Posted By 444slayer:
Thanks, I was hoping you would weigh in on this.





MartytW  [Member]
9/28/2004 9:48:35 PM

Originally Posted By TonyRumore:
I am buiding a one-off suppressed upper in .221LN for a guy right now.



OK, I'll bite, what the heck is the .221 LN?
TonyRumore  [Member]
9/30/2004 10:45:01 PM
The .221LN is a .221 fireball with a real long neck. It was designed to fire the 75gr A-Max hanging out way long, compared to how it is normally deep seated in a .223.

MartytW  [Member]
10/1/2004 8:12:44 AM

Originally Posted By TonyRumore:
The .221LN is a .221 fireball with a real long neck. It was designed to fire the 75gr A-Max hanging out way long, compared to how it is normally deep seated in a .223.




I seem to recall running some numbers on this for someone Suggest asking HAWK if they make a really long 223 RN bullet, their 338 300 gr RN works like a champ in the 338 Spectre, might have something that works well in this one too
Kaliburz  [Team Member]
10/2/2004 6:04:22 PM
Well, this is just some data "guestimation"....

The 44 Thermopylae "hypotheical" speed....

The 444 Marlin lists this for 44 cal bullet speeds:
240gr @ 2300fps
265gr @ 2200fps
300gr @ 2000fps

The 50 Beowulf lists this:
325gr @ 1950 using Hodgan Lil'Gun
325gr @ 1880 using Vihtavuori N110

I would have liked to find some data that showed "the same" powder, but no luck.

I would guess that the 44 Thermopylae would push a 44 cal 300gr bullet at least 2000fps. Might even get it to 2300fps....

444slayer  [Member]
10/2/2004 6:44:50 PM
Reloder 7 is used in both calibers, but I haven't found any Reloder 7 data for 300 gr. bullets.

51.0 grains is supposed to push a 240gr. bullet to 2400 fps. in .444

47.0 grains gives 2215 fps. for a 265 gr. bullet.


I use 56.4 gr. WC844 to get 2070 avg. vel. with the 265's. Could be loaded hotter.

I get a true chronographed 2000 fps. with the 300 gr Speers and 48.0 gr. H322. That is a pretty stiff load, though not max. It is hell in a handgun.

I will have to do some more digging

EDIT: OK, I have found a load for 330gr. Lead Gas checked bullet that lists 2007-2190fps for 47gr of reloder 7. Also found a load for 405gr. lead bullets giving 1800fps with 37 gr. RE7.I don't know thw velocity of the Hawk 400 gr. loads in 50 Beowulf with RE7.

I am going to do some major chronographing of a variety of loads soon, ,and I will post the resluts. I have some of the 400gr. Hawks, 325 Speers, 350 and 400 Sierras, and 335 Ranier FP's and HP's. I also have some of the Remington 385 gr. HP's coming in. I also have a box of factory ammo I can chrono.
Loadswap
MartytW  [Member]
10/2/2004 11:31:23 PM
While I can work up the 44 Thermo on QuickDesign and then dump it to QuickLoad and get you a more scientific reply, I have found that the following Rough Rule can give a decent approach:

A cartridge can only harnass a certain amount of energy and impart that energy to the bullet. This energy is the powder that is burned and expressed as the pressure that is generated. The maximum pressure is the maximum pressure. While load tailoring can offer better results, simplest of physics can get you a rough initial estimate.

Contained energy in the projectile is U(k) = m * v^2. While a necked version holds a little less powder than a straight one, it will get us close. Say the 50 B will do 2000 fps with a 334 gr. With a 300 gr you will then get around SQRT[(334/300)*2000^2]. Note that a smaller diameter bullet of similar weight on the same size case will suffer some velocity loss (338-06 with 180 gr goes faster than 30-06 with 180 ALL OTHER PARAMETERS HELD CONSTANT)

I would expect that the 44 T with a 300 gr bullet will do about the same as the 50B with the 300 gr bullet .... not much to be gained, heck, just look at the 458 SOCOM compared to the 50 B (and the SOCOM case is slightly shorter)
444slayer  [Member]
10/3/2004 12:05:39 AM

Originally Posted By MartytW:
Note that a smaller diameter bullet of similar weight on the same size case will suffer some velocity loss (338-06 with 180 gr goes faster than 30-06 with 180 ALL OTHER PARAMETERS HELD CONSTANT)



Yep. It's called overbore isn't it? It would still be a fun plaything (A 440 with nitrous!), and there are quality bullets that are alot cheaper in .44 cal, just like there are in .458. The only cheap .50 cal bullets are the Ranier/AA 334/335s. The good one's really cost.

Who do you get to do pressure tests so you know what your limits are when you come out with a new cartridge like the .458 SOCOM?
MartytW  [Member]
10/3/2004 10:52:30 PM

Originally Posted By 444slayer:
Who do you get to do pressure tests so you know what your limits are when you come out with a new cartridge like the .458 SOCOM?



Well, the 458 SOCOM started out in my office (and then garage) as just a hare brain idea for myself and a friend in "the business". It all just got a little out of hand after that

I set the initial pressure max equal to that of the parent brass and that met with approval from both the brass maker as "someone else in the industry who would know". Then when CorBon started loading they did the hard work, and stuck to the pressure max we originally set.

We have found that the brass will take considerably more pressure, but we do not advocate it. One customer reported a load (due to a over charge) that practically doubled the pressure compared to max. Both shooter and rifle lived to tell the tale ...

SHIVAN  [Team Member]
10/3/2004 11:01:24 PM

Originally Posted By MartytW:
One customer reported a load (due to a over charge) that practically doubled the pressure compared to max. Both shooter and rifle lived to tell the tale ...



Didn't he compress powder and such? Fired MULTIPLE times if we are thinking/speaking of the same "user".......the AR15 is a hell of a robust weapons platform.
MartytW  [Member]
10/3/2004 11:44:06 PM

Originally Posted By SHIVAN:

Originally Posted By MartytW:
One customer reported a load (due to a over charge) that practically doubled the pressure compared to max. Both shooter and rifle lived to tell the tale ...



Didn't he compress powder and such? Fired MULTIPLE times if we are thinking/speaking of the same "user".......the AR15 is a hell of a robust weapons platform.



No, Sponge was mild compared to the one we got word of, this other person grabbed the wrong powder and thought it was something else. Think 30 grains of POWER PISTOL ....
Rockrat  [Member]
10/19/2004 11:02:28 PM
Interesting cartridge the 44/50beo. Always liked the 44's. Wondering if you could just take a 440 corbon reamer and run it into the barrel a little deeper to account for the different case length. I read that the 50BEO was just a lengthed 50AE case with the rebated rim, so why not use 440 corbon dies to form the shoulder and 50BEO dies to size the rest of the case. Of course, if you had an AR10 you could just neck up the 284 winchester case to take 44 bullets. 65 gr(if memory serves me correctly) of Re7 and a 265 hornady gives almost 2600 fps out of a 23" bolt gun(my first elk was shot with this at 200 yds-perfect mushroom on the bullet) and near 2700 fps with a 240gr. Really a bear in an XP100!
TonyRumore  [Member]
10/20/2004 12:29:31 AM
Holy smokes, batman.......I can't believe 30 grains of Power Pistol didn't bust the bolt on that .458 SOCOM.......jeez, that's quite an over-load. Did the guy chrono that round?

I once loaded a Smith 1006 with a max charge of 10.5gr of Unique, but the scale wasn't really set at 10.5, it was set at 15.0!

I touched it off, (the first round from the new gun) and thought, "my god this thing has a hell of lot more recoil than my old Delta Elite." Then I found the empty case....with no pimer left in it.




FB41  [Member]
10/20/2004 8:41:04 AM

Originally Posted By TonyRumore:
Holy smokes, batman.......I can't believe 30 grains of Power Pistol didn't bust the bolt on that .458 SOCOM.......jeez, that's quite an over-load. Did the guy chrono that round?

I once loaded a Smith 1006 with a max charge of 10.5gr of Unique, but the scale wasn't really set at 10.5, it was set at 15.0!

I touched it off, (the first round from the new gun) and thought, "my god this thing has a hell of lot more recoil than my old Delta Elite." Then I found the empty case....with no pimer left in it.








I once loaded some .44 Spl with a MAGNUM charge of Unique. All I can say is I'm thankful I shot the first one in my S&W 24. Had I used my Charter Bulldog, things woulda been a LOT more exciting!