40-65: Learning what I can

[SgtDog0311]

Gunlaker, I'd be much obliged if you posted your Shiloh chamber cast.

Been giving this some more thought.

Revisiting the chamber diagrams that Don posted – Didn’t catch it the first time around but there are two numbers posted where it shows the transition (12*-45-0) in that drawing. Not sure if I’m interpreting it correctly but it leaves me wondering if you can get their Browning reamer from PTG in more than one transition angle. Sent that question to PTG.

About accommodating available brass: I suppose an option would be to have a reamer ground to fit available Starline brass but I see right off I could outsmart myself by overthinking this. I could see that you might exclude reformed 45-70 since the chamber could possibly be too tight to allow oversize cast with the thicker case wall of a reformed 45-70 case. I have a friend with a Rolling Block who has exactly that problem. To use the 45-70 he’d likely have to shoot a smaller diameter paper patch whereas his Starline accommodates a .001 or .002 oversize GG. Starline is a little short though, so he is exposing the grease groove. The 45-70 being a little longer I could see myself wishing for even a couple more grains of powder capacity down the road.

Freebore: As yet I haven't fastened on the bullet style so not sure if freebore is preferable. I’m thinking with a 3.5 transition that freebore would be of little advantage unless it allows forward seating for greater case capacity.

Probably ought to start out by selecting a bullet so better give TJs a call and see what the bore and groove diameter is of his 40 caliber liners. Thinking Creedmoor or Money in about 400gr would be good for a 16 twist.

Caution me if I'm going down a dumb path anywhere.