My 40-65 reamer was ground by PTG about 18 years ago, I ordered it to match Shiloh's reamer. My RCBS dies are marked "40-65 Shiloh Sharps .408". The reamer has a cylindrical neck of about .600 in length. The dies are made the same, Lyman and the standard RCBS dies have a straight taper from case mouth to the base of the web and will not chamber in the Shiloh chamber. Cody Ballard used the same reamer design in years past, I owned one of their 1885's in 40-65 and had to use the Shiloh dies in it as well. Others experience may differ.

If it's the same chamber as Shiloh uses then you will likely be very happy with it.  I can tell you that the actual Shiloh chamber has a 2.5 degree ( per side ) and about a 0.050" freebore.  I have no straight section near the mouth in my Shilohs though.  With the Shiloh chamber those are the best dies to use.

Chris.

The Ron Long chamber is designed to use 45/70 brass sized down to 40/65 and not trimmed to 2.10. The case length for a Ron Long chamber is somewhere near 2.140"

The following are the chamber & bore dimensions of my Shiloh Sharps 1874 .40-65 which left Shiloh 10/2017:

Working from the chamber breech to the throat:
Rim seat depth (aka rim recess): 0.070”
Rim seat dia: 0.607”
Headspace (aka rimspace): 0.071”
Chamber base (web) dia. (in front of case rim): 0.502”
Chamber length (from front of case rim to case mouth): 2.040”
Overall case length: 2.111” (chamber length + headspace)
Chamber mouth diameter: 0.4325” (see note 2 below)
Chamber transition length: 0.013”
Chamber transition angle: 45.0 degrees
Freebore length: 0.025”
Freebore diameter: 0.4090”
Leade length: 0.075”
Leade angle: 2.5 degrees
Bore (land) diameter: 0.4005”
Groove diameter: 0.4070”
Land height” 0.0033”
Bore twist rate: 14.5:1

Notes:
1)      Bore: 14.5:1 right-hand twist, 6 lands & grooves, lands: 0.070” wide, grooves: 0.140” wide
2)      There’s no evidence of a well-defined neck.  I.e. the chamber has a uniform taper from the breech to the chamber mouth.  Starting in front of the rim seat the chamber diameter drops off (tapers) uniformly from 0.500” to 0.436” about ½” from the chamber-to-throat transition step, at which point the diameter reduction continues but at a reduced rate, diminishing another 0.0035” over the last ½”.

Wayne

I have two Ron Long 40-65s and the correct custom RCBS dies. The chambers are longer and the bores are smaller than .408.  If memory serves, Rons barrels were .406.

John Rigby wrote on Feb 11^th, 2021 at 7:39pm:


Yep, you're correct. My Winchester slugs at .408.  I've used Winchester brass however. Maybe I squeezed um down.  I know I used Winchester because I shot them till they wore out and replaced with Remington. 

My Ruger slugs .406 -7.

Can someone share the PTG drawing for the 40-65 Win. Shiloh MFG. reamer or at least the drawing number? Getting ready to order a reamer and want to get the right one.