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

[cordite]

My Mahillon cape gun is a hammer, Jones underlever gun with a 12 gauge barrel on the right and a straight tapered 3.5 inch cartridge on the left side. I'm traveling at the moment so can't post pictures, but it has minimal proof marks. It is very short and light weight and the rifle rate of twist is something in the order of 1 in 45 inches. I have shot it using 450 3-1/4 brass and it seems to work OK even though it is short.
The other interesting thing is the bore is.468 inches. I bought a 450 grain Lyman mould and then realized this is obviously a black powder express round and needs a light bullet, probably no more than 300 grains. I may try paper patching a light .458 bullet next.
I have seen some discussion on another forum about a necked 3.5 inch bpe cartridge similar to the English 450 number 2 nitro round. But my cartridge is a nice straight taper. I have also read that the belgians were known for making light weight express double rifles and for making whatever the customer wanted. Any thoughts on this? I will post pictures next week when I get home. Thanks!

[Diz]

Cordite, I don't know of a 3-1/2" BP case, most everything that big was Nitro and without specifics of head and rim diameter it will be pretty hard to figure out. Do you have a good chamber cast? Diz

[mike ford]

Cordite,
Your question is a little bit confusing to me. You didn't explain where the 11.88x90 came from. I checked two different, pretty complete, sources and didn't find any such cartridge. If the designation came from a chamber cast, some misunderstandings can result. Some older chambers were cut without an identifiable leade ahead of the chamber. This results in the impression that the cartridge is longer than it actually is. The 11.88 seems to match the .468" that you reported as the "bore diameter". However, if this diameter resulted from measuring a chambercast or a "slug" driven into the barrel, then it is not the "bore diameter", rather it is the "groove diameter". This is a common mistake in use of terms. Older barrels for blackpowder cartridges were often made oversize, with the idea of leaving room for residue of blackpowder combustion. These oversized barrels worked by depending on the bullet "slugging up" to fill the barrel. This worked with blackpowder and lead bullets. The metric designation of a cartridge usually used the bore diameter rather than the bullet or groove diameter(there are some exceptions). A rifle would have been chambered for a cartridge available at the time it was made. All this together leads me to opine that your rifle is actually chambered for 11.6x83R Express (either D or E version, depending upon case taper).This cartridge is also known as 450 Long, or 450-3 1/4 in., which is the cartridge you selected to try. It is not at all unusual to find "450 cal" rifles with .468", instead of .458" groove diameter. Of course, I can be wrong.
Mike

[sharps4590]

Pay attention to what Mike says about the long leade. I ran into a chamber like that in an older, BP rifle, thought it was a neck and came very close to creating an overpressure condition. Fortunately the case was loaded with black powder or it could well have been over pressure. It was close even loaded with black.

[Diz]

Cordidte, give us an accurate head and base diameter and we'll figure it out. I was thinking a 450 BPE. Thanks, Diz

[cordite]

I will get you some more information when I get back home. I should have been more clear, .468 is the groove diameter. If it is the 450-3 1/4, would they really have expected a .458 bullet to bump up that much even with a case full of blackpowder?

[mike ford]

cordite,
Today, we have no way to really know what they expected. Over the years, I have had different 450 express loads in my "pile", but it was so "dear" that I didn't break it down to measure the bullets. We often see different 450 cal. cartridges listed as having .454" or even .450" bullets, but photos often show them paperpatched. It is not always clear if the bullet diameter included the patch or not. Furthermore, the patch material was differing thickness and sometimes a different number of wraps. Some ammo used "naked" bullets, only lubricated-not patched. Today, we would likely prefer such a bullet to be a couple thousandths over groove diameter. Our frame of reference is much different than it was 130 years ago, when their decision makers had likely learned using muzzle loaders, with bullets sometimes a good bit smaller than even bore diameter. On top of this, manufacturers had their own standards as there was no DIN or CIP, so one firm's barrels may have different dimensions than other firm's. Now, as to the question of a .458" bullet "bumping" up to fill .468 grooves, its not clear if they expected bullets to fill the grooves, or if they expected them to "bump" up enough to engage the rifling, and leave some room for residue. This is not unique to European
rifles, Antique American 45 cal. rifles also have such differences.
Mike

[Axel E]

Cordite, read the book by Graeme Wright:"Shooting the British Double Rifle". In his chapter 4 he mentions some such ideasyncrasies. Many of the old rifles had tapered bores, tighter at the muzzle than at the breech end. Also his first bp dr, a .577 x3". Instead of the nominal groove diameter .584" it was .594" ahead of the chamber and tapered to .591" at the muzzle. A .500 3" BPE was .516" rear and .512" front. So oversized bores were nor unusual.

[Diz]

In my rather limited experience with BP I find that soft lead bullets will bump up considerably when fired over black powder especially with an "express" charge. Ten thousandths would be fairly easy but this is not the case with most nitro loads. Sharps will correct me on this. Diz

[sharps4590]

Yes sir Cordite, bullets were expected to and did "bump up" that much. A hard alloy back then was 1-20 and many used 1-30, 1-40 or straight lead. For all my BP cartridge shooting I have settled on 1-25 and I can't argue with the results from several rifles. The effects of black powder on soft lead bullets is quite different than smokeless. Years ago Mike Venturino did an article on a 44-77 Sharps, darn near the same as a 43 Mauser, that had a groove diameter way over what was expected and he couldn't get it to shoot worth spit. When he went to soft bullets it became a very accurate rifle.

There is no secret to successfully loading black powder but there are a few additional steps that should be taken if the best results are to be seen. A soft lube should also be used. With the BP cartridges one isn't so much concerned with leading as keeping the fouling soft. If your rifle turns out to be a 450 BPE, 3 1/4, which I suspect is the case, you should be able to build some very accurate BP loads for it. If loading black is a direction you want to go I would suggest you get a copy of the "SPG Lubricants BP Cartridge Reloading Primer" by Steve Garbe and Mike Venturino. Paul Matthews also has a couple books on loading BP and a search by author should turn up them. Grahme Wright also addresses some BP loads, as Axel alluded to. Their methods all differ a little and depending on the rifle one or the other should work admirably. I've had to use "tricks" from all of them to get various rifles to shoot.

Shooting black is a bit more.....tedious, maybe.....than shooting smokeless but any pressure concerns are essentially gone. That and when you get a good rifle and load combination it's pretty satisfying to see a sub-MOA group using means and methods that are well over a century old.

As an example here's a target I shot with a Johann Outschar stalking rifle chambered for a 9.3 case I remember as being 62mm long. Without looking up the load I remember it as being 9.3 X 72R cases shortened to 62mm, 58 grains of 3F Schuetzen powder, Federal 215 primers, a .020 card wad over the powder and with this cartridge I had to use a pea sized "grease cookie" over that wad, then another .020 wad all under a 196 gr. bullet cast 25-1. The reason for the "grease cookie" is that the bullet didn't carry enough lube to keep the fouling soft to the end of the barrel. Group was fired at 100 yards and the rifle was benched and bagged, open sights. First shot is at bottom edge of paper, second in the 5 ring then one last adjustment and the next 3 for group in the 9 ring. Rest assured that was an exceptional day for the guy doing the shooting.

[cordite]

Excellent! I have all the books mentioned and load and shoot several black powder cartridges. I'm just used to having my bullets one or two thousands over groove diameter so my first thought in this case was to look for a fatter bullet.

[sharps4590]

Then all I did was tell you a lot of stuff you already knew....lol! Yea, they will bump up quite a bit with black if they're soft.. If you do want a bigger bullet Accurate molds can cut one, as can others...and I suspect you probably knew that also.

[Axel E]

Just another, maybe the first example of the upsetting of undersize soft lead bullets at the "push" of black powder: The Swiss "Eidgenoessischer Feldstutzer M 1851", the first "smallbore" (under .50") military rifle:
http://www.germanguns.com/upload/sho...to-ID-this-Gun
This rifle had a .410" bore with 8 grooves .2 mm deep. It used a solid , no hollow base for expansion, 262 gr pointed lead bullet, bound into a greased cotton patch, in front of 62 gr black powder. As this was a muzzleloader the .40" bullet + patch was at least as small as the bore diameter to allow it being pushed down the bore on loading. On firing this rather long lead slug set up enough to engage the rifling.

[sharps4590]

Another example I personally know of is a friend of mine has a Whitworth replica with the hexagonal bore. He did not have the mold but used a 520 gr. Lyman 457125 lubed and loaded. Bob said when he recovered the bullets they were bumped up to look like the mechanically fit Whitworth mold. He also said it was amazingly accurate out to 500 yards.

[cordite]

20160127_174216.jpg
Will try to post some pictures.
The case on the left is a new 450 3.25. The case on the right was fired through the rifle with a stout blackpowder load you can see how it has expanded.
Measurement just in front of rim in inches: factory .537 fired .555
half way down case: factory .500 fired .547
case mouth: factory .472 fired .520
I will have materials here for a chamber cast in a couple of days.