Hello folks. I have been using the 'find' function the last few days, looking for info on brass for use in a .455 S&W that I just acquired. Thus, I have resurrected this thread from April of some year?

My findings, while somewhat confusing, have helped somewhat.

It appears that Buffalo Arms modifies .45 colts to work as MkI's...ie: narrower rim thickness & ~.890 case length.

Also Hornady made some MkII's ie: 0.770 case length.

Starline talked about making one or the other or both, but apparently never did.

I guess the Fiocchi's are not worth messing with.

So, here is where I'm at:

It seems like headspace average for non-recessed S&W's is ~0.066 (no cartridge) and the average rim thickness is ~0.060, so I am shooting for 0.006" with brass for this thing.


.45 auto rim are closer in length to MkI and have plenty of rim to narrow (.090 to .040)
Diameter is a little under though. Kinda scarce too, although available.

.45 Schofields @ 1.109 have the largest diameter rim but also would be the most expensive to modify.

I guess .45 Long Colt is it then.
So I shortened 6 to 1.000 OAL.
They go in the cylinder but still have the stock rim thickness (~.060)...too thick.
I tried them 1 at a time so as to not have to tear the gun apart to get a cylinder-full out of the gun. At the .060 rim thickness, they begin to bind-up when coming into the firing position. So, I figure out a way of holding them in my lathe & cut the rim back from front a little at a time. I did not want to go directly to ~.039 if I didn't have to as that is pretty thin and I still have to load them.
I got 6 of them rotating freely @ about ~.050 rim thickness & 1.000 case length (no bullet).

I depth miked the cylinder & it is ~0.946 which explains why I am able to get these in & rotate them.

I intend to shorten them further...but am not sure to what length?

I found some reloading data using Fiocchi brass in the MkI style that mentions case length as being 0.910 (can't believe they stretched from 0.886) so it must be mfg. tolerances?

I can handle 0.910 so I may go to that interimly?

I have read that the MkI (the longer of the 2) was a black powder cartridge pre-1900's, and that the Brit's found that with the shorter MkII case (0.770) smokeless loads were more efficient.
(sort of like the current trend of the SSM's in rifles)

I don't like the looks of the 0.770 case, so I will probably stay inefficient...ha ha

Sorry to bore any of you, but if someone has an un-rechambered .455 and can depth-mike the cylinder from entry-end to the step, I'd like to know what they come-up with?

Open for any criticism or thoughts.


Thanks

__________________
John