Loading 577-450

[Colt Fanning]

Howdy,
I recently acquired a Francotte Martini rifle in 577-450 caliber and am intrested in loading for it.  I have several questions.
It is the .460 in.  version and has Henry Rifling.

Does the usual bullet .001 in. larger than bore dia. and made of 1 in 20 lead apply to Henry rifling?
The original British Military version of this cartridge was paper patch.  Are there any considerations to loading for this cartridge with
a non patched bullet?
I will probable load with 55 grns of 2f powder, fill up the case with corn meal and compress.
Thanks in advance for any info.
Colt

[Dick Dastardly]

Lyman would have you believe that 0.001 over is desired.  I've found that to be true in all the black powder guns I've owned.  Yes, the paper patch would take up some room, but there's no reason your gun won't shoot mild alloy bullets just fine.  I'd slug the bore of your gun rather than take published data and get a lube/sizer die that sizes the bullet a thousandth over.

Lotsa fun with that gun.

DD-MDA

[rifle]

I'd find out if the gun originally was fired with a 1-20 alloy or softer than that since,what I understand, the Henry rifling has a majority of the bullet very tight to the bore. Like the majority of the bore is very tight to the bullet.

I have a cap&baller Belgian Colt Army that has been barrel sleeved with the Henry type rifling. The ball is the .464 size taken down to .454 inch swagged by the chambers and the majority of the barrel diameter inside is .445. Most of the barrel inside is .445.

Some sort of fouling free rifling I thunk. Like the Holland and Holland was back then.

Anywhoooo.....the alloy may have to be pure lead. I'd try to research the alloy originally used in the rifle. Maybe go to the "Cast Boolit" forum.

[Montana Slim]

Hard to say what will shoot best in your rifle. My Pa has a couple...or is it three? including a carbine (I think)....and they all don't shoot accurately with the same load/bullet.

Easiest route (IMO) to a good shooting bullet will be to try a few 45-70 bullets and paper patch them. My dad was able to do it, so I'm sure HE would say anyone can. There is some great info out on the Martini sites, just a google away. Downloading the brutish cartridge is wise...those things have some hefty recoil.

Slim