I've read this cartridge results when you take a .45-70 case, and run it through a .40-65 sizer. The resulting case is a little longer than a standard .40-65, but the brass is easy to obtain.

This uses a .406 nominal bullet diameter?

I've been thinking about ordering a lighter caliber in an 1877.

I believe all the 40-82 varieties use a 45-90 case.
The Ron Long 40-65 uses the 45-70 case and does in deed come out of a 40-65 die about a tenth of an inch longer. At one time RCBS offered 40-65 RL dies.
A fun little 40 caliber cartridge for most things 600 yards and under would be either the 40-50 ss or the 40-50 bn. The 40-50 ss uses 303 brit cases and the bn I believe uses 4065 cases trimmed to length and fire formed. Maybe Nathan will see this and chime in he runs those later two.

I have a .40-70(M) Win in a Ballard Rifle & Cartridge High-Wall that's based on the .45-90.

It's very similar to the .40-82 Crossno and was developed about the same time and approved by the NRA for BPCS. It was designed by a couple local guys in MO and I borrowed their reamer to have Garbe & Co. chamber my rifle.



Basically a straight neck, reamer was cut for "slip fitting" bullets in Starline .45-2.4" brass with the grease grooves covered.

The .40-50 SBN is a hoot to shoot. I had a Shiloh Saddle Rifle with a 26” half round barrel. It was light and recoil was non existent. I put a Leatherwood scope on it and it made a heck of a deer gun. The .40-50 SBN is made from .45-70 brass

I know nothing about this stuff firsthand.... However, happened to read a Venturino 40-82 article last night that mentioned 45 Basic brass.

May or may not be of interest....

https://gunsmagazine.com/our-experts/the-40-82-wcf/