BP .38 Spl Loads in Colt 1851 Cartridge Conversion

[SPJ]

Hello all,

I am looking into getting a cartridge conversion of a Uberti Colt 1851, and I have been wondering how powerful of a black powder cartridge I could use in the gun, and what I could feasibly make for it. I am hoping that maybe some of you others have already tried this out on your own and that I can learn from you.

From what I've read in this previous post (http://castboolits.gunloads.com/show...B-P-Ballistics) and in this old issue of Shields Magazine from 1907 (https://www.google.com/books/edition...sec=frontcover) it seems that the most powerful load for a 38 in blackpowder is with 23 grains of powder and a 160 grain bullet. The thing is though that no one says what the OAL of the cartridge is with that load. The sight for the Kirst Konverter of the Colt Navy (https://www.kirstkonverter.com/1851-61-colt-navy.html) says that their cylinders are not for cartridges "exceeding 1.425" overall length". So can a load of 23 grains of powder and a 60 grain bullet be compressed to 1.425 inches? If not then what other bullet types could be used? I'm not sure if other conversion cylinders like the Howell Old West have that same length limitation, and if anyone can clear that up for me to then I would appreciate it.

I would definitely want to use a hollow base bullet in order to engage the .375 rifling of the Colt Navy barrel, but I cannot find molds for HB bullets meant for a Colt. The best that I could find may be the Rapine .358149, but they are no longer made. The next best thing I can think of is taking out and using the HBFP used in these 38 Long Colts (https://www.midwayusa.com/product/1000515467). If anyone knows how I could find a mold for bullets like those please let me know.

To sum things up again, before I go investing a lot of money into this, can anyone confirm for me that I can compress a bullet of 160 grains to 1.425 inches with 23 grains of powder in a 38 special case? And if not then what type of bullet can be compressed to that length with that powder load? I know that I may have an easier time with the flat end of a wad-cutter, but I want to go with a RNFP because of improved aerodynamics, and simply for the challenge.

Thank you

[Jniedbalski]

If the 23 grains won’t fit use a little less. The article if it’s from 1907 they used balloon head cases then and probably did hold the 23 grains. If you use the newer brass probably not. I have seen a bullet mold for this that uses a healed rim fire style bullet with a shank smaller than the bullet.

[Nobade]

Modern 357 cases will hold 21 grains. 38 spl cases are closer to 19. And yes, you're likely looking at getting a custom mould to make boolits for that setup. Accurate makes moulds designed to accept your custom core pin that will work. You'll be needing to make them out of pure lead to get them to work. All in all there are much better ways to shoot a revolver, IMHO.

[AntiqueSledMan]

Hello SPJ,

I'm not sure about the .38 Special, I load .44 Colt Original with heeled bullet.
I can easily fit 1.9cc (approx. 27.9gr) of 2F in that one, could even squeeze a little more.
My favorite is Black MZ, to bad it's been discontinued.
You could check on the Colt Country Forum, there is a Conversion Area.

AntiqueSledMan.

[SPJ]

If the 23 grains won’t fit use a little less. The article if it’s from 1907 they used balloon head cases then and probably did hold the 23 grains. If you use the newer brass probably not. I have seen a bullet mold for this that uses a healed rim fire style bullet with a shank smaller than the bullet.

Modern 357 cases will hold 21 grains. 38 spl cases are closer to 19. And yes, you're likely looking at getting a custom mould to make boolits for that setup. Accurate makes moulds designed to accept your custom core pin that will work. You'll be needing to make them out of pure lead to get them to work. All in all there are much better ways to shoot a revolver, IMHO.

I will add that I plan to use Goex fffg powder since I understand that should allow the most space. Do you know where I can find balloon head cases if necessary?

I've also found a supplier of 9mm 135 grain (HBFP https://shopwilsoncombat.com/BULLET-...o/B9-135-HBFP/), does anyone know who they perform in 38 special cases?

[SPJ]

I also found this old thread from The High Road (https://www.thehighroad.org/index.ph...or-357.795086/) with others saying that they can get 30 grains in 38 special brass with compression, and one specifically stating they can get 25 grains into their Starline brass. So I think I will look into buying brass from Starline then.