slm9s,
What chambering will you be using?
I necked down a .300 RUM and pushed the shoulder back about .100" to create a longer neck. It holds 109 grains of powder to the top of the neck. It holds 101 grains with a Barnes LRX 127 grainer. It will push a Nosler AB 140 to at least 3,400 feet per second. I have not pushed it to see where pressure signs start. Ben at Hornady named it 6.5RUMLN.
After the .26 Nosler came out I discovered mine is only 6% larger. But they use a short neck, so I would not use that cartridge.
