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huntinguy
07-07-2009, 06:21 AM
Has anybody here converted (okay, added a second cylinder) a Colt SA in 41 Long Colt to 38-40?

It seems like the best way to keep an old 41 shooting without going through the reloading troubles that a 41 has.

How big of deal would this conversion be?

JCHannum
07-07-2009, 07:07 AM
Swapping cylinders is a rather common modification for the SAA. If you haven't done it, I would recommend getting the Kuhnhausen manual for the finer details of fitting and timing.

http://www.gunbooks.com/colt_sa.html

38_Cal
07-07-2009, 09:30 AM
The original heel-base bullet for the .41 Long Colt had an outside diameter of .410", while the 38-40 uses a nominal bullet dia. of .401". You may be ok with very soft bullets, but hard cast will just lead up your bore and give poor accuracy.

David
Montezuma, IA

radkins
07-07-2009, 10:03 AM
The original heel-base bullet for the .41 Long Colt had an outside diameter of .410", while the 38-40 uses a nominal bullet dia. of .401". You may be ok with very soft bullets, but hard cast will just lead up your bore and give poor accuracy.

David
Montezuma, IA


I think there has been a lot of confusion about doing this for the reasons you are mentioning. I saw one at a gun show recently and the owner said it functioned quite well.

Maybe this can explain it.

www.en.wikipedia.org/wiki/.41_Long_Colt

38_Cal
07-07-2009, 10:21 AM
Radkins, I hadn't run into any references to a smaller diameter (38-40 sized) bore before. Thanks for the link. Huntinguy, you will probably want to slug the bore on your Colt to determine which version you've got before making the investment in the new cylinder!

David
Montezuma, IA

bob308
07-07-2009, 03:50 PM
they both have the same bore dia. so all you change is the cylinder that is what mike venturino did in his book shooting the colt single actio

skeeter skelton also talks of doing the same thing. he even had a .41 that some one reamed the cyl. out to .38-40

andy_b
07-09-2009, 01:28 PM
I think there has been a lot of confusion about doing this for the reasons you are mentioning. I saw one at a gun show recently and the owner said it functioned quite well.

Maybe this can explain it.

www.en.wikipedia.org/wiki/.41_Long_Colt


if that really is the case, and i was going to have a 38-40 cylinder fitted, i would just have the cylinder machined to match the bore of the revolver, and then have a set of reloading dies machined to match as well.

andy b.

JCHannum
07-10-2009, 07:38 AM
Slugging the bore is a good idea to see just what you have. Manufacturing procedures and tolerances were not what they are today and there is more variation in bore dimensions than in today's guns.

With that knowledge, if reloading, a sizing die can be used to size the bullets before loading. Custom dies are not needed.

Do keep in mind that any of the SAA's have a collector value, and load so as not to destroy the gun. Much enjoyment can be had with light loads and lead bullets. Any modifications should be to the replacement cylinder to allow returning the gun to it's original condition by simply re-installing the original cylinder.

huntinguy
07-12-2009, 11:49 AM
38 cal. I was trying to get away from the healed bullets and not shoot the .387 dia. undersized “minie”s)

JCHannum, I was trying not to affect the collectors’ value of the gun. That is why I was thinking I could get away with the 38-40. For some reason I thought they had the same bore. I was confused…

I think I will check around and see if I can find some hollow base bullets for the 38-40 before I give up on the conversion. At least then the bullets should be closer to bore size and not rattle down the barrel. :D

Thanks all.

38_Cal
07-12-2009, 04:24 PM
If you can find a second cylinder, ream it out as needed. I would make up some dummy cartridges with bullets the proper diameter needed for your barrel (groove dia. + .002") if it is larger than the throat of the chambers. You can, if necessary, open up both the chamber throats and the necks with very careful use of chucking reamers. If necessary, open up a sizing die to accomodate the larger diameter bullets. To open up a mold, use a small boring bar for the bands in it, at least on the bottom two bands. Cast a few bullets first to determine what diameter your alloy casts in your mold, determine how much you need to enlarge the mold, and bore it out by that much. Of course, if you really want to make a HSM project out of this, get a smaller diameter single cavity bullet mold, say, for a .30 caliber rifle, and make up a hollow base bullet mold from it. The original base of the bullet becomes the nose of the new design.

Keep us informed of your progress, please!

David
Montezuma, IA

radkins
07-12-2009, 10:48 PM
3 That is why I was thinking I could get away with the 38-40. For some reason I thought they had the same bore. I was confused…



Maybe not so much at all, unless you have a very early version then the barrel should be essentially the same bore.

andy_b
07-13-2009, 11:50 AM
If you can find a second cylinder, ream it out as needed. I would make up some dummy cartridges with bullets the proper diameter needed for your barrel (groove dia. + .002") if it is larger than the throat of the chambers. You can, if necessary, open up both the chamber throats and the necks with very careful use of chucking reamers. If necessary, open up a sizing die to accomodate the larger diameter bullets.

David
Montezuma, IA

that's exactly what i would do.

andy b.

weestrommer
09-02-2009, 12:58 PM
they both have the same bore dia. so all you change is the cylinder that is what mike venturino did in his book shooting the colt single actio

skeeter skelton also talks of doing the same thing. he even had a .41 that some one reamed the cyl. out to .38-40

there was more to this, the gun you mention (Venturino) was done by me when I worked in a pretty famous shop, this gun had a .403 bbl. actually if you look at enough old guns you see bbls. for the .41 colt ranging from .397-.413(groove) the best plan is to slug your bbl. now that you know its size. get a .357 cyl. and rechamber it for .41 special(you just shorten .41 mag brass.100) and shorten your .41 mag seater by .1. (this is for a bbl. that comes in at .410ish) if your gun has one of the .403 or .400 range bbls then fitting the .38-40cyl. and honing the throats for the larger bullet dia. is the way to go. you can load up to about a .403 in the typ. colt cyl. till the neck dia is too small.

there are actually 2 chambers used in the .41 colt, the old one that had no throat and has to have a heeled bullet too shoot well, and the latter pattern that had a conventional throat for the hollow base inside lubed version. I have had in my hands an originalSAA that was shipped from colt with the later style chamber for the later ammo that had a .413 dia bbl. and .397 throats in the cyl. and to top it off a lot of that hollow base .41colt ammo had .386 dia bullets. I know it had a hollow base bullet but did they ever think it would shoot well that way? (it would not hit a target box 2 feet square at 15 yards with any regularity and if it did the holes were profiles not round!!!!)

by the way the winchester .41 colt ammo loaded in the 1980s was loaded with black powder. The gun I mention above was owned by a gun writer that had "come into" so 40k rounds of this ammo and wanted to use it up, and sent us the gun because it shot so poorly.

as to loading the .41 colt I have loaded several thousand rounds using whitehorse .41 cal heeled bullets and winchester cases. you just need to have a collet crimper. they are easy to make or Lee witll make you one for about $25.