the 400 Corbon

Ill start by saying this was a caliber whose concept really got my attention.
the 400 Corbon is a 40 caliber cartridge based upon the 45 ACP.
This allows its use in many popular 45 autos without any serious modifications aside from a barrel which may or may not require fitting, and a recoil spring replacement.
The stock 45 mags remain in use while the breach face extractor and ejector still thinks its working on the parent 45 ACP.
In essence, offering a two caliber option like a TC contender, however in an auto loader.
It seems a plausible concept, yet sounds too good to be true since the ballistics are dead on the heals of the mighty 10MM.
So does it work? and if so, what good is it?
these questions prompted me to decide to play with it.
here is the loaded 400 along side its parent 45

With that we are ready to answer the first question .... does it work?

ummmm ... matter of fact, it DOES
and its function was very close to flawless.
This implies a fly in the ointment ... well a gnat really. In actual practice it tended to be a little sensitive about magazines with two out of my 5 mags glitching on the second to last round. Once segregated, feeding was flawless.


In this picture we get to what seems to be an accuracy issue. Honestly, all things considered this wasnt as bad as it appears. this was shot at the 50 yard line compensating with hold over for its low point of impact ... with a well savaged shooting hand that was getting a little tore up and tender from the 1000 round range marathon in both 400 and 45.
I was just a little flinchy by this time, while the 1911 was so dirty it should have choked .. but refused.


The frame of the Springfield 1911 could use a little dressing of the edges for extended sessions like this.

None the less it was time to go see what the 400 was good for and off we went to a secluded pond known to be frequented by a variety of critters.
with its 1300+ FPS performance on a 150 grain cast HP, its something of an honorary magnum capable of dis-assembly procedures upon bunnies limb rats chipmunks and crows.
The grass will be quite green after the red fades. This particular load seemed to present itself as a good varmint round. A solid pointed bullet with the volume turned down to the 1100 range should make for a fine small to medium game cartridge. Im quite confident that with a heavier bullet in the 170 - 180 grain area pushed to close to full potential should have no trouble bagging deer sized game.
Quite promising indeed.
not only does it work, its good for something too

Obviously, the 400 Corbon is a reloaders cartridge, somewhat like the 10MM it rivals.
But unlike the mighty ten which nearly faced extinction, being based upon a prolific case as the 45ACP is, it has little danger of ever being sidelined as the 10MM nearly was.
cases are easy to reform for the 400, most, in my case, didnt even need to be trimmed after going through the sizing die.

So is it worth the trouble ... I think so. the 400 Corbon earned my respect and myself as a proponent of this wonderful yet obscure wildcat round

I gotta tell ya, I yawned when the .357 sig came out. This is the same thing only supersized. But you know what????? This kinda piques my interest for some reason. Where do you get barrels for this? is any of the ammo commercially loaded?? 10mm balistics from a pretty much stock .45.......I'm kinda liking it......

thats pretty much the same hook that sunk into me, thus making this whole thing possible.
Midway USA has it covered for both ammo and 1911 barrels and recoil spring.
Ill try to track down some resources to cover other 45's as well

Pistol and Gun Accesories | EFK Fire Dragon
these guys seem to cover a few "noneleven" 45's Sig p220's, HK USP's, SA XD's, Glock 21's(yeah I know Im asking for it) may play.
Starline makes preformed brass, Lee precision and RCBS produce dies.
There are likely more resources which Ill add to support this caliber

have owned one of these for several years. mine is on a para-ord. p-14 in stainless steel. had alex hamilton install a set of sights and knock off all the sharp edges. used to be my car gun. forming cases is simple. start with new 45acp cases. i used winchester but federal work good too. one pass through the sizer and done. no trimming just deburr. my experience in loading is all with lighter bullets. in the 135-155 weight class. pop cans at 100yds from the bench is easy. recoil is less but noisier. i did not change recoil spring,still has the 16lb. in it and has about 2500 rds on it now. i do use full elngth guide rod and recoil buffers. lots of good loads out there and cor-bon makes ammo if you can find it and afford it. like was said earlier, 357 sig only bigger.

of the load data Ive found on the caliber, bullet weights range from light 135's on up to 180's.
I'd like to see the popularity of this cartridge take on a cult following from what I've seen of it so far.

It does have a cult following already, a very small one.

The cartridge was introduced 16 years ago (1995) and fizzled shortly after. Whenever you see ad hype for bottlenecked pistol cartridges they give you all the pros, but never the cons. And the pros aren't really pros either. Ballistically it is similar to the .41AE, which really was a great idea, but with the larger butt it only gives you a lessened magazine capacity, and it is only marginally better than the .40 S&W, but again there are drawbacks.

The biggest problem with it's lack of success is that it was designed by an ammo maker and not a gun company, such as the .357 Sig and the .45 GAP. That is the only way to make a mediocre cartridge popular.

True that its birthing place, being an ammo maker rather than a gun maker and a specialty one at that. its pedigree is only slightly better than bubbas tool shed.
yeah we arnt going to gain mag capacity going to it, nor are we going to lose any either since its targeted for 45 auto platforms and mags.

the data I have for it puts a 155 grain bullet at 1300 FPS using unique
I use a chrono and have found it can exceed 1300 with a little room on the pedal ... this is the 10MM's turf.
in data yet to be tried .. it can go up to 180g stating 1100fps.. I cant vouch for that as yet. My instinct tells me that it will pull a 357 sig on this heavier bullet and fall short.
which may start the list of cons. to go along with minor sensitivity to mags and a lower point of impact than the parent 45. both can be dealt with fairly easily.
another con not so easily dealt with is the fact that it was born into obscurity and never made it out of the ghetto ... people just are not aware of it

...nor are we going to lose any either since its targeted for 45 auto platforms and mags.

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Actually you do lose something by using a bottlenecked case instead of a straight walled one. If you converted your 1911 for instance to .40 S&W, 10mm or even .41 AE you would have gained a round.

If you're looking only at numbers such as velocity/bullet weight you may be asking for trouble. I'm not sure what pressure cap Cor-Bon has on the cartridge but that doesn't mean it's safe to shoot in any .45 platform. A perfect example is the 10mm auto. When it first came out it was a real hottie, but after different gun makers adopted the cartridge, mostly Colt, SAAMI dropped the maximum pressure on the cartridge because it was breaking guns. The old 1911 design was never made to handle all that pressure.

If you don't care about the pressure issue, J.D. Jones had made a conversion for the 1911 years ago called the .41 Avenger which was a .45 ACP necked down to take .41 mag bullets. There were three levels of loading data for it depending on what brass you were using to make it from, regular .45 ACP, .45 Magnum or .308 Win., the last two required a little more work than just necking down. I don't think it sold even as well as the .400 Cor-Bon.

being a wild cat it isnt really set to a concrete pressure standard, but comes with a guideline which is that of the 45 acp's +P loading for the most part, and a hair hotter for extra light bullets like 135 grain .. at least that is how I understand it from my research into it.
10MM was chewing up early delta elite frames which gave it a bad rap. Later revisions helped them handle the full wrath of the Norma factory ammo, which was loaded to the bleeding edge of physics.
400, even in its higher pressures is still less than that of the mighty 10MM
Conversion from 45 to 10MM or 40S&W is far more involved than 45 to 400 as well. in the 400, its a barrel, and a spring. the transition from 45 to 10MM/40S&W means barrel, spring, slide, ejector and extractor as a bear minimum. frame modification for ramped barrels in the worst case ... this mod should be considered permanent ... 400 transplants can be treated like a TC contender barrel swap. That and the 10MM like ballistics are its drool points for me.

Looking at data from Accurates loading manual, 2nd edition, they show max. pressures for the .400 Cor-Bon in the 35,000+ psi range. Max. pressure for the .45 ACP +P is 23,000 psi.

But, the case doesn't determine max. as much as the gun does.

I once used a Norinco frame as the basis for a platform that, with two slides and a conversion unit, would fire .22 LR, 9mm, .38 Super, 10mm, .41 AE, .400 Cor-Bon and .45 ACP. They all used the same ejector and slide stop and there were only three recoil springs. I found that while there are parts specific to each caliber, they aren't always required when switching from one to the other. My favorite was the .41 AE by the way, just my luck.

Isn't there some max bullet weight restriction, at 165 gr I believe? Something about the short neck. A heavier bullet when seated properly to oal will sit too far past the top of the shoulder inside the case.

One of many reasons why 10mm>400 cb.

So why stop at the .400 Cor-bon, they got a .440 Cor-bon now

Who says we have?

billdeserthills said:

So why stop at the .400 Cor-bon, they got a .440 Cor-bon now

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The 440Corbon was born into obsolescence with the Desert Eagle and has long been discontinued. I don't know of any other handgun that was chambered for the round except for maybe the Encore. And although I own two of them, the Desert Eagle has its own limited following.

Wildcatters continue to experiment with different chamberings every day.

ohiococonut said:

Wildcatters continue to experiment with different chamberings every day.

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I don't dislike any cartridge but there are more and more that are nothing but the same old thing with a new name. Most of it has to do with gun manuafacturers looking for a proprietary cartridge just for a marketing gimmick. Unfortunately there have been a number of pretty good ideas that never got the attention they deserved because the gun makers either didn't understand the advantages or wanted all the credit and made a close copy.

400 data goes up to 180 grains, which may or may not be able to be pushed a little farther by way of bullet design.
It should not be at all hard to make up another 20 - 30 grains at the nose via a WFN type design favored by hunters and unlike a straight wall case, such a bullet will not cause the slide to lock open due to contact with the slide stop. This is theory of course, Im not sure how much the bottle neck case affords us in getting rounds into the chamber. There is enough argument in each camp of the 400/10mm debate to go back and fourth for decades. 400 is a reformed 45 auto. You'll never run out of brass to load with it, though you may have issues beyond the 180 grain mark. 10MM can throw a little more bullet without much hassle, but it nearly went extinct on us once. if it does it again, you cant stretch a 40S&W case to keep her fed.

Quite the many years ago I read an article about the use of zinc bullets at way over the standard pressures. the argument made was the dwell time at that pressure allowing the practice. I wouldnt push this concept. Its one of those that looks great in the lab environment but gets pretty spooky afield, despite the engineering principals involved.
with a 155 grain cast bullet, I got 1330 FPS on the chrono with more rounded edge on the primers left than my 230 grain 45 load.
I have some room on the pedal yet and might have potential to make 1400 FPS on this bullet .. but 1275 - 1350 is where I wanted this one to live. I seem to be achieving the goal without exploiting the dwell time theory much, if at all.

It seems we have some people aware of the cartridge .. no surprise there. this place is filled with gun people.
Im also aware that some may have seen it printed in a manual before, but never knew what it was for or never heard of it at all.
Ive got my barrel and dies to keep my wildcat well fed, there's nothing more for me to gain from it, aside from a pile of ammo and a compilation of load notes.
It was just time to pass word along to the next guy that it exists, and is ready to be your load bench mistress.

The point I was making was be informed before you make the jump on a 400cb conversion. There are other things you may have to deal with besides a simple barrel swap. Ok, at the end I couldn't resist putting in a plug in favor of the 10. We 10mm people jump on any op when we have a world audience.

I have a friend in PA who tried the 400cb in a 1911 and had the same problem I had when I put a 357 sig barrel in my Delta. The cartridges nose dived with straight column mags, either 40 or 10mm. Works fine with staggered mags. My 239 has dedicated 357 mags.

I have some 451 Detonics virgin brass and I have had my own wildcat dreams, like a 41?

Anyone remember a similar wildcat from around the late 70's or early 80's in, as I recall, 357 cal?

Was it by Baines & Davis?
357/45 B&D ??????????

I saw some right sporty shooting with those.

it was a 357/44 bain and davis. was quite common to have a cylinder chambered in this for a 27 or 28. the older hodgdon loading manual have loading info for this. had one years ago and played with it some. woked great on coyotes for as far as you could hit them. using a sierra 125 jhc bullet they are devastating.

perrazi said:

it was a 357/44 bain and davis. was quite common to have a cylinder chambered in this for a 27 or 28. the older hodgdon loading manual have loading info for this. had one years ago and played with it some. woked great on coyotes for as far as you could hit them. using a sierra 125 jhc bullet they are devastating.

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Not the one I was thinking of, but thanks for that clarification.
The cartridge I'm referring to was definitely based on the 45 ACP.
It was the same drop-in situation- all you needed was a barrel.