Conversion Cylinder Technical Question

[rbertalotto]

I bought and installed a pair of Kirst 45LC conversion cylinders into a set of Pietta 1860 Colt Sheriff models.

One concern I have is the chamber dimensions. I can't figure out why there is a step in the chamber for a 45LC. Looks like the chamber for 40S&W or 45ACP or other cartridges that headspace on the mouth. Not a cartridge that headspaces on the rim.

I've attached a drawing that shows the Kirst chamber in comparison to a standard 45LC chamber.

The pistols shoot fine, but there are flyers. I have another set of 1858 Piettas with the Howell cylinders and they too have this step, but not as pronounced. The 1858 revolvers do not exhibit the flier issue and are quite accurate. I'll measure those cylinders and post later.

Using Cowboy 45 brass, the 45 SLIM bullet at .452" diameter is jumping .405" and then trying to get through the step in the chamber. This simply doesn't sound like a good thing!

I'm thinking these pistols might shoot better if the step was tapered or simply removed all together.

Comments?

http://images16.fotki.com/v378/photos/2/36012/10295030/nversioncylinderchamberdrawing-vi.jpg

[rbertalotto]

When I pulled the Howell cylinder to measure them, I didn't realize the chambers were tapered at the mouths. This makes a lot more sense and might be the answer why the 1858 revolvers with the Howell chambers are so much more accurate with the short Cowboy 45 brass.............(That "unknown taper" could easily be calculated with some simple math)

http://images51.fotki.com/v103/photos/2/36012/10295030/owellConversionCylinderdrawing-vi.jpg

[Hang Fire]

I have a 5 shot .45 LC Kirst cylinder for my 58 Remmy, and have none of the problems you described.

If the chamber throat is too small, will make for a undersized boolit when it enters the bore and lousy accuracy

[rbertalotto]

Hangfire, it has nothing to do with the size or shape of the chamber throats. This whole thread is about a bullet jumping nearly a 1/2" and then trying to get through a hole with a very abrupt shoulder.

See the difference between the Kirst cylinder and the Howell.

BTW, Walt Kirts sent me an email that he is going to do a bit of research for a possible solution for those of us that are shooting Cowboy 45 Special brass in these cylinders. Stay Tuned!

And............

I slugged and Cerosafe cast my barrels on the two 1860 revolvers. Both were exactly .448 with both Cerosafe and with a soft led slug.

http://images51.fotki.com/v303/photos/2/36012/10360662/DSC_4238-vi.jpg

http://images109.fotki.com/v785/photos/2/36012/10360662/DSC_4245-vi.jpg

I also photographed the forcing cone on the barrel. Looks like Pietta did an excellent job on both barrels. The large diameter is .452

http://images16.fotki.com/v368/photos/2/36012/10360662/DSC_4240-vi.jpg

http://images54.fotki.com/v627/photos/2/36012/10360662/DSC_4246-vi.jpg

I also foced a lead bullet as far as I could into the 1858 revolvers. Unlike the 1860, the barrels are not removable so I wasn't able to slug the whole bore. But for the first 3/4", they both slugged .448 also.

And here is a picture of the cylinder....

http://images54.fotki.com/v104/photos/2/36012/10360662/DSC_4249-vi.jpg

[Seth Hawkins]

I'd return them. You'll never get them to work with that step in the cylinder. It needs to be tapered.

[bigted]

what is this "short cowboy brass" you speak of and does all conversion cylenders require them for function?

[Hang Fire]

Not being into CAS and sure there is a reason, but I have often wondered about the using of short cowboy special cartridges? Why not just use light loads in a regular .45 LC cartridge?

OTOH, have read that the 1873 Colt SAA issued to troops, in many instances were not issued .45 LC cartridges. Due to there also being the S&W.45 Schofield issued which used the shorter .45 S&W and would not accept the .45 LC. In attempt to solve the problem, arsenals supplied both .45 S&W and .45 LC cartridges, which still led to troubles.

[rbertalotto]

http://images56.fotki.com/v362/photos/2/36012/10295030/withwords-vi.jpg

The image above illustrates the Cowboy 45 brass.

The 45LC was the "magnum" of its day. And today it is a huge cartridge. Downloading large cartridges can possibly lead to predetonition. Where the powder is so low in volume, when the gun is level, the primer has a clear shot to the base of the bullet. It is theorized that the primer pushes the bullet into the throat of the barrel and then the powder lights behind it, and the bullet becomes a bore obstruction. The entire energy of the cartridge then proceeds to blow up your revolver. Not good!

And trying to download black powder in such a huge case is simply folly.

The Cowboy 45 brass allows you to VERY safely download cartridges with both smokeless and BP.

[rbertalotto]

I'd return them. You'll never get them to work with that step in the cylinder. It needs to be tapered.

Actually, for the distances we shoot at in CAS, they worked quite well at two matches I used them in., The only time I missed a target was when the wind stopped blowing and the smoke from the BP made it impossible to see the targets!

I'm sure the step would effect a 100yd shot, but at 10-15 feet, it's no issue.

But that said, I like things to be right so I ordered a special reamer from Dave Mason to remove the step and create a proper chamber.

[rbertalotto]

I'd return them. You'll never get them to work with that step in the cylinder. It needs to be tapered.

Actually, for the distances we shoot at in CAS, they worked quite well at two matches I used them in., The only time I missed a target was when the wind stopped blowing and the smoke from the BP made it impossible to see the targets!

I'm sure the step would effect a 100yd shot, but at 10-15 feet, it's no issue.

But that said, I like things to be right so I ordered a special reamer from Dave Mason to remove the step and create a proper chamber.

[lathesmith]

Air space in the cartridge case is a no-no with Black powder; that's the main purpose for the 45 Cowboy Special, as Roy stated above. The 45 CS saves the bother of having to use fillers and other things to download the 45 Colt. For shooting Cowboy matches, many competitors want the lightest loads they can get, and the 45 CS makes doing this easier.

lathesmith

[Hang Fire]

All this sounds like a perfect solutions to a nonexsistent problem, which I don't have when shooting my conversion Cylinder as designed.

If I had knowingly bought a gun chambered 22 long rifle and then made it my choice to shoot nothing but .22 shorts in it. Don't think I would have much of a gripe as to accuracy against the maker of the gun.

[Hang Fire]

#11
lathesmith
Vendor Sponsor

Join Date: Nov 2006
Location: Springfield, Missouri
Posts: 1,213 Air space in the cartridge case is a no-no with Black powder;

Then why no problem with a percussion Sharps which has all kinds of air space?

[rbertalotto]

Then why no problem with a percussion Sharps which has all kinds of air space?

Sorry, I don't understand. How do you have airspace in a percussion Sharps. That bullet darn well better be tight up against the powder or up against a wad that is compressing the powder or you will ring your barrel / chamber.

And as far as shooting the proper bullet in the proper chamber............

What the hell fun is that!

You can order the conversion cylinders with 45ACP chambers, and then the CB45 brass fits perfectly...........but I didn't go that route because every once in a while I just might want to load up full and have at it!

And I sure hope you don't think this thread is anything near a "gripe". Kirst makes a beautiful piece of art as a cartridge conversion cylinder. No gripe whatsoever. This is all just part of the fun of playing with guns!:p

[docone31]

If that is a 5 shot cylinder, are you sure it is not for the .45 Schofield?
That would explain the step. LCs are a little long for the cylinder.
I can get 30gns in the Schofield. Makes a fun load.
Good and snappy.

[Hang Fire]

Sorry, I don't understand. How do you have airspace in a percussion Sharps. That bullet darn well better be tight up against the powder or up against a wad that is compressing the powder or you will ring your barrel / chamber.

Then you know nothing about about the paper cartridge percussion Sharps.


You can order the conversion cylinders with 45ACP chambers, and then the CB45 brass fits perfectly...........but I didn't go that route because every once in a while I just might want to load up full and have at it!

Are you saying you can shoot a rimmed .45 cartridge in a rimless .45 acp chamber?



Using Cowboy 45 brass, the 45 SLIM bullet at .452" diameter is jumping .405" and then trying to get through the step in the chamber. This simply doesn't sound like a good thing!

I'm thinking these pistols might shoot better if the step was tapered or simply removed all together.

No gripe?

[rbertalotto]

If that is a 5 shot cylinder, are you sure it is not for the .45 Schofield?
No, it is for 45LC. They fit perfectly. Too long for 45Scofield.


Then you know nothing about about the paper cartridge percussion Sharps.
That would be correct! This is one form of shooting I've not embraced....Yet!..:bigsmyl2:
But, in a paper patch cartridge there is an air space between powder and bullet?


Are you saying you can shoot a rimmed .45 cartridge in a rimless .45 acp chamber?
Yes......The Kirst 45ACP cylinder will accept Cowboy45, and the 45ACP S&W revolvers and others will accept 45AR (Auto-Rim)

[Hang Fire]

One can also load the PP Sharps with loose powder and ball to the top of the chamber, but when you close the action, there is still mucho air space in the breech block for the powder to fall back into. So why doesn't it cause all the problems you stated.


Yes......The Kirst .45ACP cylinder will accept Cowboy45[/quote

To all that without provenance I call BS. The Kirst .45 acp conversion cylinder I saw head spaced on the case mouth with cartridge head very close fitted, and had no space for a .45 auto rim or moon clip. It was the same as the Ruger Blackhawk quick change cylinders for the .357/9 mm or .45 LC/.45 acp.

[quote]and the 45ACP S&W revolvers and others will accept 45AR (Auto-Rim)

if I understand what you are stating, I again call BS. The 1917 Army revolvers were made by both Colt and S&W for .45 acp so it could shoot .45 acp only.

There were two versions of the 1917 Army revolver, in first version the .45 acp head spaced on the the case mouth and head was close fitted to the recoil shield. With no means to extract fire cases without poking them out with a rod of some sort, the Army was not satisfied. In the 2nd version S&W came up with a shortened cylinder in the rear and using moon clips, this modification was then done to Army’s satisfaction by both Colt and S&W.

The .45 auto rim was an afterthought for the civilian market and not even invented by Peters until 1922, the rim only takes up the space of the moon clips for which the revolver was originally designed for.

[TXGunNut]

I wouldn't be concerned if they shoot well. I fired many tens of thousands of .38 Spl rounds thru a few S&W revolvers chambered for .357 Mag. S&W chambers have a step very much like the one in the Kirst cylinder. Some folks felt a cylinder chambered for .38 would be more accurate but we never could prove it, most PPC revolvers are capable of 1" @ 50 yards regardless of whether the cylinder was chambered for .38 or .357.

[rbertalotto]

I'm going to leave Mr hangfire alone......(I sure as hell hope you were smiling partner, when you used the words BS in my general direction.....[smilie=s:..)...And continue with the thread I started.

(Just to be sure there is no confusion, the KIRST 45ACP cylinders will indeed digest Cowboy45 rimed brass quite nicely..........)

Today I took my 2 Remington 1858s to the range. I sold the Howell cylinders and bought two gated Kirst cylinders. The Howell cylinders were great, but I wanted to be able to load quicker at the reloading table during a CAS match. The Howell cylinder needs to be removed from the revolver to load.

http://images32.fotki.com/v1090/photos/2/36012/10288332/DSC_4285-vi.jpg

http://images55.fotki.com/v659/photos/2/36012/10288332/DSC_4286-vi.jpg

One in 45ACP and the other in 45LC. I wanted to see for myself if there was any difference in accuracy between a chamber with near no bullet jump and one where the bullet "free falls" for nearly a half inch before it is controlled by the chamber mouth.

Both cylinders fit both revolvers beautifully. So I can use one revolver with both cylinders.

I was shooting the 45APC cylinder with Cowboy45 Rimmed cases and the 45LC cylinder with the same.

This is a picture of the two chambers side by sude:

http://images31.fotki.com/v1084/photos/2/36012/10288332/DSC_4281-vi.jpg

My loads are 3.5g Trail Boss under a 170g 45SLIJM Big Lube bullet.

Velocity out of the 45LC cylinder, with the long jump was 650fps average and the 45APC cylinder was slightly less at 615fps average.

The 45LC cylinder experienced a few fliers, but was still quite accurate. This target was shot from a rest at 20':

http://images36.fotki.com/v1176/photos/2/36012/10288332/Text2-vi.jpg

As was this target, but with ten rounds:

http://images34.fotki.com/v1076/photos/2/36012/10288332/45lc10shot-vi.jpg

But the 45APC cylinder, shooting the RIMMED Cowboy45 cases with the proper chamber, was amazingly accurate!

http://images109.fotki.com/v785/photos/2/36012/10288332/45apctext-vi.jpg

http://images16.fotki.com/v369/photos/2/36012/10288332/45apclargetext-vi.jpg

I also shot 45LC brass in the 45LC cylinder. With this combination, obviously there is no "jump" and accuracy was very good.

So my conclusion......If you want a super accurate revolver to shoot Cowboy45 brass, get a cylinder with the proper dimensions.......I have no intention of shooting 45LC in either of my C&B conversions, so I should have bought all the cylinders in 45ACP and then use the Cowboy45 rimmed cases in them..........Live and learn!

But for CAS, these revolvers are more than accurate enough. In fact, I have four Rugers (2 New Model Vaqueros and a couple BHs, and three other Uberti SAA revolvers, and none of them shoot as accurately as these conversions. My Pietta 1860 Army conversions will perform just as well as the 1858 Remingtons.

http://images44.fotki.com/v220/photos/2/36012/10360662/DSC_4182-vi.jpg

As always, comments are always appreciated..............Thanks!

[rbertalotto]

I wouldn't be concerned if they shoot well. I fired many tens of thousands of .38 Spl rounds thru a few S&W revolvers chambered for .357 Mag. S&W chambers have a step very much like the one in the Kirst cylinder. Some folks felt a cylinder chambered for .38 would be more accurate but we never could prove it, most PPC revolvers are capable of 1" @ 50 yards regardless of whether the cylinder was chambered for .38 or .357.

Thanks for the reply TX, But I have to differ.

I just went into the safe and looked at over a dozen 357 and 38 Special revolvers I own.....6 S&W, a Python, three Rugers a Rohm, and a Taurus.....and not ONE of them has a step like in the pictures I've posted. If you look in the cylinder you can see a transition from the chamber to the mouth, but it is gradual. It might look like a sharp step, but if you take some type of long rod (I used a stiff aluminum arrow shaft) and slide it along the wall of the chamber it will simply slide up and over that area. Where in the Kirst cylinders it is abrupt and stops the aluminum shaft cold!

Now I'm not saying that maybe other revolvers have this step, all I'm saying is in the years I've been working on and playing with revolvers, I've never seen it before. The only chambers I've ever seen with an abrupt step like this is where the cartridge headspaces on the mouth.

After my range session today, I returned back home and field stripped the revolvers. I inserted a bronze brush from the mouth side of the chamber and I was able to push out a nice lead ring from a few of the chambers. Usually half moon in shape. This, I believe, is caused by the bullet being totally unsupported as it transitions from the cartridge to the mouth of the chamber, and hitting this abrupt edge and shaving off lead. At "Cowboy" distances it doesn't seem to matter, and in fact, after a couple of shots maybe this area fills in with lead and improves the accuracy............If I remember, the fliers I experience do indeed happen when I first start shooting............If nothing else, all this is very interesting to me!

Safe shooting!

[rbertalotto]

Just to keep the conversation alive, here is the SAAMI spec for a 357 magnum chamber..........Notice the nice 6 degree slope to transition from case to mouth...

http://www.saami.org/PubResources/CC_Drawings/Pistol/357%20Magnum.pdf

[rbertalotto]

And the SAAMI spec for the 45LC

http://www.saami.org/PubResources/CC_Drawings/Pistol/45%20Colt.pdf

[TXGunNut]

Thanks for the reply TX, But I have to differ...-rbertalotto


Wow, didn't realize it was that abrupt. Most folks don't even notice the ones in a S&W cylinder. If it's shaving lead there's a problem but as you pointed out it's still plenty accurate for some games, especially after you get a ramp built up.
Interesting indeed.

[lathesmith]

Roy, now all you need complete your gated conversions is an ejector, like so:

[Hang Fire]

(Just to be sure there is no confusion, the KIRST 45ACP cylinders will indeed digest Cowboy45 rimed brass quite nicely..........)

Odd, no pictures of the rimmed ammo in a Kirst .45 acp cylinder, with the loading gate closed on one included

So I will make the same request you asked of me on THR. Lets see some pics?

[rbertalotto]

Lathesmith, those revolvers look great!

I actually bought the ejectors for the 1860 Colts

http://images24.fotki.com/v873/photos/2/36012/10360662/DSC_4261-vi.jpg

But they really damaged the great look of these revolvers. And they don't make unloading any quicker at the unloading bench during a CAS shoot.

Yesterday at the range, as I was shooting my Cowboy45 rimmed cases in my 45APC cylinders (or at least I thought I was, I must have been dreaming!......:-P ) I was also shooting the 1860s. I removed the ejectors and found it was much easier to unload with my brass "hinge pin".

http://images51.fotki.com/v103/photos/2/36012/10288332/DSC_4133-vi.jpg

And these Cowboy45 cases only need to be moved a very short distance to be removed. In fact, 75% of them simply fall out when the cylinder is spun.

I think I'm going to sell these ejectors and buy another cylinder for my remaining 1858.............This Cylinder Conversion stuff is addictive!

[lathesmith]

Roy, that's some great-looking revolvers you have there. Conversion revolvers to me have the appearance of being cobbled together with various spare bits and parts, that one happens to have lying around...which, when you think about it, is pretty much exactly what they were, and are. I guess that is one of the reasons I love these things so much, they are firearms evolution in real-time, and you can imagine it happening over that 20- or so year period, in the mid- to -later 1800's.

I see you also have some great leather there, and that really helps set 'em off!

[Johnny_Cyclone]

Hummmm. after reading this maybe I should acquire a chamber reamer that will put a 6° 30' B or less throat angle on my .45 Colt cylinders..so maybe I can resist the urge to purchase 45ACP cylinders :???:

Wonder if there are any members on here who can make one. Maybe a rental fee with a few bucks going to the: "Keep Castboolits running fund" so we can all use it.

I mean know one has to have it, but it'll make good conversation at the next event...

I'm not here to shoot against you Holiday.
(I beg to differ. We started a match stage we haven't finished)
Ahh..I'm just here to fool about
(I'm not....and this time it's a sanctioned match)
-Johnny looks fearful, then embolden-
ok, lunger
(say when)
-cue: sound of the stage being shot (pop pop ping ping...pop pop ping.. silence)-
(ahh Johnny,...you ain't no daisy, you ain't no daisy a'tall with out a 6 degree throat job)
-Johnny stomps off-
(I'm afraid the strain of having inferior chamber spec's was more than he could bear)
:)


The angle on the .357 chambers (same in .38 Special) could be why my .38 Short Colts shoot so well in the longer chambers.

[TXGunNut]

Conversion revolvers to me have the appearance of being cobbled together with various spare bits and parts, that one happens to have lying around...which, when you think about it, is pretty much exactly what they were, and are. -lathesmith


Dunno, I've only looked at a few and was very impressed by the materials, workmanship and design. They don't have the grace and simplicity of the original c&b revolvers but I like them. Those 1860's are starting to grow on me, BTW. Even with the ejector rods.

[John Boy]

Hangfire, it has nothing to do with the size or shape of the chamber throats. This whole thread is about a bullet jumping nearly a 1/2" and then trying to get through a hole with a very abrupt shoulder. So, why post here? The category is about black powder not gunsmithing

[Hang Fire]

I guess I really am missing something here. OP was all about the long jump the boolit was having to make and then hittng the far away chamber throats when shooting rimmed short CB brass in the .45 LC cylinder.

Then comes the story about shooting the same rimmed short CB brass in a .45 acp cylinder and how accurate they were in that cylinder where the chamber throats are much closer to the boolit?

If all that is true, then why the hue and cry about the.45 LC cylinder problems was having, then saying the .45 acp cylinder works great for the rimmed CB brass?

[TXGunNut]

I found most of the posts interesting and informative and the photos were enjoyable as well. I'm easily entertained and all but clueless on conversion cylinders so I enjoyed the thread.

[uscra112]

In blackpowder days they made gallery cartridges by loading a small charge and shoving the boolit right down onto it. Boolit sunk as much as 3/8" below the case mouth. I've got one in my collection. So why is there a .45 "Cowboy" at all? But even so those cylinders should have a taper leade into the throats.

[rbertalotto]

Yes, I've heard of these gallery cartridges. I'm going to experiment some day with this. Sounds like a good way to down load the big 45LC case.

The Cowboy 45 is just another way to skin the cat and take even more of my dwindling bank account.........:drinks:

Thanks!

[Springfield]

For those who still wonder, the 45 Cowboy special is there for those who wish to shoot their 45 Colt guns but would like a downloaded cartridge, especially for BP. In cowboy shooting we only have to hit the target, not kill it, and less recoil can reduce our times and give us a better score. Yeah, we could just buy new 38 pistols but that is too expensive for poor folks like me. What, you never shot light 38 specials in your 357 Magnum pistol? Yeah, I knew you did. Personally I just shoot 44-40 and be done with it. rbertalotto, glad you like the 45Slim bullet, it is my design, with all the drawings for the bullet done by 45 2.1. I sent the specs to Dick Dastardly and now he is having the moulds made, along with my 44Slim and 38Slim designs. My cowboy alias is Springfield Slim, hence the name. It was a lighter, "slimmer" bullet so the name seemed to make sense. Had to call it something!

[TXGunNut]

For those who still wonder, the 45 Cowboy special is there for those who wish to shoot their 45 Colt guns but would like a downloaded cartridge, especially for BP. In cowboy shooting we only have to hit the target, not kill it, and less recoil can reduce our times and give us a better score...


Less powder, less lead, less recoil, faster times, higher scores. Still looking for the downside. Looks like fun, too.

[Ecramer]

Nice looking revolvers. I have the Howell conversion cylinders on a set of full-sized 1860 Armys I bought for CAS. I've yet to buy any C45S cartridges, but my plan is to buy a .45 Colt chambered Spencer rifle from Taylors and use C45S in it and the conversions. I have no worry about the "long jump" in the chamber -- no more worry than I would have shooting a .38 Special in a .357 Maximum chamber.

As for the "step" the SAAMI specs above show it -- and it's present in most older revolvers chambered for .45 Colt that I've examined. The later chambers without it are what might be called a "cost saving measure" by the manufacturer."

And although none of my current revolvers have this feature, I still think that the rim should be recessed as it was on revolvers cut for the old balloon head cases, even if this is a pain on the range when you're trying to show you've loaded only five chambers <grin>

[rbertalotto]

Hey Springfield,

Thanks for chiming in on here.

My two conversion revolvers are simply amazingly accurate with your 45SLIM boolits.

We're talking extremely small groups out to about 50 feet.

I just had Lathesmith whip me up a special die for my new Star lubrisizer and lubed up a few hundred boolits last night.

I got the lead pots heating up as we speak to cast a few thousand boolits tonight. Need to get my inventory up for the coming CAS season!


As for the "step" the SAAMI specs above show it

And not to beat a dead horse...........Oh, what the heck, let's beat the **** out of it!
The SAAMI specs DO NOT show a step, but a nice gradual incline to guide the boolit to the throat........This is the way God meant a chamber to be cut......:razz:

[Hang Fire]

Nice looking revolvers. I have the Howell conversion cylinders on a set of full-sized 1860 Armys I bought for CAS. I've yet to buy any C45S cartridges, but my plan is to buy a .45 Colt chambered Spencer rifle from Taylors and use C45S in it and the conversions. I have no worry about the "long jump" in the chamber -- no more worry than I would have shooting a .38 Special in a .357 Maximum chamber.

As for the "step" the SAAMI specs above show it -- and it's present in most older revolvers chambered for .45 Colt that I've examined. The later chambers without it are what might be called a "cost saving measure" by the manufacturer."

And although none of my current revolvers have this feature, I still think that the rim should be recessed as it was on revolvers cut for the old balloon head cases, even if this is a pain on the range when you're trying to show you've loaded only five chambers <grin>

I have a .44-40 Colt 1873 SA mfg in 1886, and it doesn't have the recessed chambers for cartridge rims. IIRC, the balloon head cases were still being made up into the 1950s.

[Ecramer]

I have a .44-40 Colt 1873 SA mfg in 1886, and it doesn't have the recessed chambers for cartridge rims. IIRC, the balloon head cases were still being made up into the 1950s.

I admit I'm surprised by that -- just goes to show that the more you learn, the more you learn how little you know.