Anyone have any information or ideas on necking the 45 2.6 down to 25 or 280 caliber for a long range case for the singleshots that require a rimmed case

argolee,

the 45-basic case is the same diameter as the 284/9,3x64 Brennecke cases are. Let your imagination soar!

Rich
DRSS

is there a computer program that can help me in figuring out the pressures and all the details conscerning such a conversion like case capaicity pressure would necking down to a a 7mm on a 2.6 inch case lengthen or shorten the case

The 45 basic case is close to the belted mag base. You could look at the 257 Wby, 7mm Rem or wby and guess from there.
Maybe the 7mm STW? run the reamer in most of the way, 2.6", then cut down stock loading dies. You may have to form the sholder and neck in something with a more gradual angle.

Quickload won't calculate the internal capacity, but it is good for guessing on loads. Once your case is formed, just measure the water capacity.

New 7mm STW brass measures .510 on the base,the 7mm STW reamer measures .514 at the base for a clearance of .004.

New 45-2.6 cases measure .500 on the base.

A 7mm STW reamer ran in 2.6" would cut a chamber .5133125" in diameter with no runout.
That is an awful lot of clearance with a .45-2.6 case.

WC

would something like this be able to get 3000 fps with say a 140 grain at a low pressure That is what I am shooting for possibly a 45 3 1/4 necked down

9,3x64 Brennecke Rimmed would be a fine cartridge. I have reamers for a 9,3x64 necked down to 6mm...a sort-of 6-284x2.6" rimless. Have your gunsmith cut the rim recess and be happy.

Rich
DRSS