Anyone heard of a 3.5 inch bpe cartridge - 11.88x90?

[cordite]

20160127_174216.jpg hope this works

[cordite]

DSCF1776.jpgproofmarks

[cordite]

DSCF1777.jpg more proofmarks

[cordite]

DSCF1778.jpg also comes with a set of shotgun barrels not shown

[cordite]

DSCF1779.jpg cylinder choke in shotgun barrel even though barrel says not for ball.

[cordite]

DSCF1780.jpg I have owned it for many years but have not used it much because of being uncertain about the proper cartridge.

[cordite]

Top of barrels inscribed.
ARM DE SARM LE Comte DE Flanders
H Mahillon, 25 Rue Desert Eperonniers, Bruxelles

[Nathaniel Myers]

Very interesting! Will continue to follow this thread. Even learned a bit about black powder (which I don't get to shoot much of).

Always amazing to me the wealth of knowledge here!

[sharps4590]

Nice looking old combination gun. Right up my alley, Jones underlever and hammers.

cordite, just from the photo's of the cartridge case the one on the right looks more correct to me. The unfired case seems to have too much taper....but that's looking at pictures as opposed to having the cases in hand.

[Diz]

Cordite,

An old Kynoch drawing I have shows the .450 Express base diameter at .548" and the case mouth at .479". Pretty close to your actual measurements of the loaded round. I can't find anything in between the .450 BPE and .475 BPE that is remotely possible as to what this is. I think the odds are against it being a Sharps or something like that. Maybe there is someone with a more extensive reference collection that could come in. Right now my vote is for a 450 3-1/4" BPE.

Thanks, Diz

[cordite]

20160129_172628.jpg
ok,this is a rough chambercast. Wow is it big. The chambercast is next to the 450 3.25 case fired in the gun. It is exactly 3.5 inches from the front of the rim to the rifling. So the first question; is that extra quarter inch a lead into the rifling or is the cartridge really 3.5 inches long? I suppose another question is; does it really matter as I will likely be using available 3.25 brass in it anyway?

[cordite]

I didn't get a good cast of the rim but it is a thin rim like the 450.3.25. Otherwise the chambercast numbers pretty much match the fired case numbers I posted earlier. The expanded 450 3.25 case seems like a good fit. A paper patched 457 bullet should work well and allow me to not have to size the brass much if at all. One problem with using a .458 bullet and letting the bullet bump up to .470 is that the brass would have to be resized a lot each time to hold a .458 bullet.

The rifling measures .470 in front of the chamber, 7 grooves, and a slug at the muzzle measures .468. I more carefully measured the twist rate and it is 1:28 inches.

[Nathaniel Myers]

Can you make a better chamber cast? Is that Cerrosafe?

From the quality of the picture and the quality of the photo it is hard to tell, but it ALMOST looks like there is 1/2" (guessed from you 1/4") lead prior to the rifling. Look at the difference in tooling marks, the taper is rough. Can you measure any taper for the lead?

Based on the info you have, I would probably use 3.25 cases. There is always some form of lead, or transition into rifling.

[sharps4590]

1-28 twist would definitely be for a short, light 45 cal. bullet. Good eye Nathaniel, I believe you're correct.

[Axel E]

There is always some form of lead, or transition into rifling.

Not in such early rifles. The chambers of my very early Rigby double rifle .500 3" BPE, originally sold in London to a Mr.Heath in 1870, are of similar configuration. Hardly visible in the photo. Just after the chamber, 3.05" long, the shallow Rigby rifling, 7 grooves double the width of the trapecoid lands, starts. The "leade" from end of chamber to full depth rifling is .1" long at best.