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Hi, I'm looking into making a high velocity small caliber .40 S&W by necking it down. The inspiration came from the .357 SIG. I was thinking about necking it down to 7mm (.277 caliber) or anywhere from 6 to 6.5mm. Is this possible to do with the .40 S&W case or are the pressures too high? Already have a pretty cool title, 7mm Komodo.
 

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Hi, I'm looking into making a high velocity small caliber .40 S&W by necking it down. The inspiration came from the .357 SIG. I was thinking about necking it down to 7mm (.277 caliber) or anywhere from 6 to 6.5mm. Is this possible to do with the .40 S&W case or are the pressures too high? Already have a pretty cool title, 7mm Komodo.
We tried it with the 38/45. But sizing was troublesome and than there were feeding problems. It was great when it worked
 

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You might want to use the 10mm auto case - it is a bit longer, and the prob with necking down pistol cases for wildcats is usually a short neck.
 

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Discussion Starter #5
.224 Boz is a little too small of a caliber for what I'm looking for. A 10mm case might be a better idea, thanks. Perhaps an 80-100 grain projectile would work, I like the idea of a spitzer pointed bullet in a handgun round. What ballistics would this cartridge achieve? Does anyone know if there is a program online where you can sketch the idea of this round? I only have it on paper and I couldn't seem to buy RCBS load.
 

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In the mood for a long tale about bottle necked cartridges in revolver cylinders?


Guess the first production was the way over tapered .22 jet in the S&W 53. Everyone had trouble with that one setting back when fired, blowing the "shoulder" forward, and setting back against the recoil shield tight enough to lock the gun up. Normal recomendation back then was to keep the chambers and ammo as clean and lube free as possible (so the case would grab the chamger and not set back so hard).

BUtr, back about 1973-1974, I worked two summers for the gurmpiest, most short tempered gunsmith I've ever met. (not 100% sure he's dead, so lets just call him "Frank" working in Chalmette Louisiana). Ran his shop like a mid-evil woirk shop, moving from one guy's work station to anothers, giving out blistering insults when you did wrong, and a quiet "grunt" when you were doing right.

Any way, he figured out a way to make the Mod. 53 work, but it wasn't quite orthodox. Not sure where he learned to do this, or if he thought of it himself.

He increased what would normally be called headspace (space between the cylinder and the recoil shield), but added a little steel ball to the recoil shield right above the centerfire pin opening. (The S&W 53 had a kind of dual firing pin in order to work with the .22LR inserts the revolers came with, and he used that space).

So the headpsace wasn't wrong when measured agains that mostly sunken in ball, just seemed that way from the chambers not lined up with that ball.

When the round fired, it set back against that ball rahter than the whole flat of the recoil sheield. Which let the cylinder roate just fine even when the gun got a bit dirty.

Maybe he liked me...maybe he just didn't care if I whent deaf...but I got to go to the local range and test fire it. I ran 37rounds (all he had leftof factoy loads) though it, double action/single action, and it never siezed up (although it did get filthy, louder than ****, scared little chilren, and made a bad name form myself at that range).

Was a little bit sticky on DA, as I think the ball put a little dent in the case rim as it set back (or cock-eyed the rim), but would shoot (a little stiffly at first roation) DA. No problem with the leverage of SA.


OK..fast forward a couple of years to about 1976.

Was a nice old Colt Besily, looking really pretty with about 90% finish remainging, case colors good, with an odd 8" barrel with no markings. Priced really nice, but no one was buying becasue it was not nearly a Colt-Colt.

Nubers had it as a 1906 version, had been recylindered and chambers in one of the shortened versions of the K-Hornet, probably a version of the K-Chuck, a floating firing pin/hammer mod, and a cute little adjustable sight dovetailed into the top strap and a new "ramp" type front strap.
(no paper-proof, but belive the work was done by Christy's Gun Works..probably in the 1950's.)

Saw it as under priced, but a good bit of $$ spend back then on a teacher's salery, for a gun that 1976 Colt colletors had not serious use for (other than parts).

So I bought it. After a few test shots, brought it to Frank.

He adjusted the headpsace a bit, and installed the same type of little hardened steel ball (this time just below the frame mounted fireing pin).

Again, could crank off 40 rounds of ammo without getting the cylinder to lock up.

Different range...but still scared children, made the chickens stop laying, cows off their milk, and generally made a pest of myself....these things are LOUD.)


SO,,,to any and all bottle neck revoler fans,will mention that bottle neck cartridges might work great when the cylinders and ammo are kept clean/oil free...they kind of suck when they get dirty. BUT there seems to be a modification that can help that.

Even the .17 HRM rimfires have had their problems with dirty chambers and case set back, although it's not as drastic as wildcat centerfires (which are usually pushed pretty hard in pressure).

Also remember a .357/44 Bains and Davis round, and a modeification to that round produced.

Basically the .357/44 B&D was a long tapered necked down .44mag case. Had some of the set back problems of the .22 rounds above if not totally clean/degreased.

Was some company that decided the idea was good, but could do it differently and cheaper. Rather than make a new cylinder in .357 B&D, they made little plastic (likely black Delrin) "turtle necks: for the cases. So the case was formed to .357 B&D, but the plastic collor fitted on top of the case so it was dimentionally the same as a .44mag case...and used a .44 mag cylinder.

It worked, the stright case stayed stright and didn't set back....but of coruse, some one had to chamber a .44mag into that cylinder and try to fire it down a .357" barrel with the ruslts you might expect (and likely some legal action trying to blmae the maker for the owner's stupidity), and that idea when belly-up in no time.


The only other onw I've seen was a conversion of a 1917 .45ACP Colt to 38/45. That one worked prety well with target type loads....maybebecasue of the 1/2 moon clips taking up some of the set back, more likely becasue of the lite target type loads used.

So that's the sum-total of one old guy's experience with bottle necks and revolvers.

So I wish you luck....bottle necked cases and revolers are not an easy road.


BTW:

Evidently Frank decided to ride out the 2005 Hurricane at his hole/shop. On the dead list, but not sure if a body was ever found.
 

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Man, I won't even try to kibbitz this one, except to mention that The CCI attempt was called the 38-44 Bobcat. I never knew that some idiot blew himself up shooting a 44 Mag. out of one of those 38 revolver's chambers. Betcha he only tried it once??
 

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.40 S & W based wildcat

Static -

Howdy !

Case oal is the challenge area, IMHO.

You'd have a very abbreviated neck lg, no matter what shoulder angle is utilized.

Useful case capacity of the wildcat would also be an area of question, after giving up capacity to form the new short neck and shoulder areas.

For a sample 7mm case based on a long version of the 9mm round, take a look @ the 7 X 33 Sako.

*** You might also want to try experimenting w/ varying lengths of the .35 REMINGTON case. ****
I found during my wildcatting of the case ( to make basically a .357 B & D "Rimless " ) that .35Rem case' ID remains a constant .40" cal from the shoulder area all the way down to about .125" above the case' web. So... you could pick whatever final case oal you want to try, and see just how much case oal you really need to include the desire shoulder " height " and neck lengths
" Learning by doing ". ( I was wildcatting Remington-brand .35 Rem brass ).

For the rimless .357 wildcat I mentioned, one could utilize ""N" frame .45ACP " Moon Clips " to make the case fit in an "N" frame application ( w/ a correct case oal adjustment ).

Other thoughts:
- You can do some rudimentary case forming for the above wildcat, using a stock .358Winchester FL die, and .35 Rem brass. Then, trim neck lg to whatever you like.

- Another .35" cal handgun wildcat w/ a shoulder that comes to mind is .357AutoMag.
I wildcatted .357AutoMag by increasing the cal to .358" calibre, so that I could shoot .358" cal rifle bullets in a bench-rest grade single shot bolt action rifle. I formed my brass using both 6mm BR and 7mm BR brass, the Lapua case being SR primer size.

Shooting pointy rifle bullets in a handgun application can be problematic, as even the FB bullets have some length to them, compared to the some what shorter and often lighter conventional handgun bullets. That longer length bullets could end up being rather deeply-seated into the case, and available case capacity of a short case based wildcat is already a challenge.


With regards,
357Mag
 

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Discussion Starter #9
Too much case length requirement for a handgun?

That's a very interesting point when it comes to the spitzer bullets being a problem in handguns. Maybe making this into a carbine rifle would be a better idea as it would gain more velocity and better energy ft lbs with more aerodynamic bullets. A .357 SIG in a carbine length barrel is very appealing, however not produced all that much. It'd be nice to see something like the caliber I am thinking of in a Beretta CX4 Storm or Hi-Point Carbine.
 

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I had a Ruger Hawkeye for a while. LOUD is an understatement but fun to shoot. Sure wish I had it back.

For those that don't know, the Hawkeye had a horizontally pivoted breach instead of a cylinder. The chamber was in the barrel.
I've had several Model 53s but mostly as trading material. I do have a bunch of 22 Jet brass if anybody needs it.
 

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Thanks...Bobcat...yeah, that's the one.


Only a couple of slightly bottle necked revolver round ever really met with a lot of popularity, and those were seldom pushed too hard (32-2, 38-40)...guess the 44-40 kind of counts, although it's not much of a shoulder.
 

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Static -

Howdy, again !

The .358" cal wildcat I mentioned above ( formed in a .358 Winchester die ) holds just a couple grains less than a .357AutoMag, when formed @ the typical "Magnum" length of 1.290" .
More powder could be held, if formed w/ a longer base-to-shoulder dimension; and shorter neck lg.

You'r right about the potential bennies of shooting a handgun-sized case in a "carbine".

My carbine was assembled using a Wichita WBR1375 single-shot benchrest action, a heavy walnut/walnut laminated stock, a Ken Burns converted 2oz trigger; and a custom Red Scherer 22" SS 5-groove 1-16 .357" calibre barrel.

I had J.D. Jones @ SSK Industries do the chambering in .357AutoMag; however.... set-up as a .358" cal carbine. That allowed me to use .358" cal rifle bullets. And.... although J.D. warned me that my chosen barrel length of 22" might actually result in reduced velocity; i stuck with for asthetic reasons.

I originally had the custom SS barrel cut, with the idea of shooting it chambered in .35 Remington... in then-new Cast Bullet Association matches. I ended up not going that route', and the barrel sat un-used for 20yr.

I decided to go w/ the .358" cal AutoMag project, and use the rifle for both 100yd benchrest shooting, and NE Indian groundhogs.

While 180gr FB bullets shot really well in my carbine, the lights-out accurate bullet was Remington's
.35" cal 150PSP. The scoped rifle was capable of 3-shot 5/8" groups @ 350yds.... something I was able to shoot mutiple times. It was also lethal on groundhogs out to 350yds, and suprisingly....
" shoot-through" was not a problem ! I think the 150PSPs shot so well because the were "plated" and not conventional jacketed, therefore could obturate well to fill the rifling.

My favorite accuracy/field load was 24gr WW296 under the 150PSP, and FED SR Match primer.

Lot of fun to be had with one of those tyoe carbines.


With regards,
357Mag
 

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I think you'll find that most successful (?) instances of a straight-walled pistol case necked down to something smaller were not so ambitious as what you are proposing. While it seems intuitive that a 40S&W case necked down even further than .357" should be useful, the problem becomes the length of the bullets and the pressure caused by impingement on case capacity. Going from 45 to 44, from 44 to 375, or from 41 to 35 are all small enough changes to not run into issues. Another good example is going from 9mm to 30 Luger.

Indiana has some very unusual cartridges requirements, when using a rifle for deer hunting on public land. These unusual regulations have resulted in a great many 35-caliber wildcat cartridges, including one based on a necked-down 460S&W cartridge. I have a rifle chambered in 358 GNR, which is a 44 Super Mag case necked down to shoot 35 caliber bullets. It is probably a good example of a reasonable limit on this kind of development. What has been determined, as a result of this flurry of wildcat development, is that you can only make the "nozzle" so small before the volume of gasses flowing through it can no longer create the velocity hoped for at the beginning of the endeavor. That is where longer barrels and stronger actions come into play.

A 16.5' barrel on an Encore action opens up a wide range of possibilities, but the strictures of internal ballistics will ever hamper the velocity obtained by pistol cartridges necked down to shoot the smaller caliber bullets. For a spectacular failure of such, please review the (short-lived) history of the 256 Winchester Magnum, a cartridge that saw but limited success even when chambered for the TC Contender.

Another thing you'll find, if you research both JD Jones and Gary Reeder wildcats, is that a great many of the ideas one might wish to try have already been done. The ones that haven't been done...well, there's usually a good reason for that, but not always.
 
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I have always felt the 30-357 had a chance of making it in a lever action of some sort. Also would make a nice revolver round.
 
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