About 10 years back, I was doing a lot of loading for an M1 Garand. IIRC, I was using 47.0 grs of IMR4064 with a 150 gr bullet. That leaves a lot of empty space inside the case, that you can't use in the Garand, probably why the M-14 was developed. The more I looked at it, the more I was impressed with the -06 case. It has enough powder capacity to do anything that reasonably needs doing. Standard head size, cheap brass, no belt, yada, yada, yada. After a few more years went by, I decided to build a series of rifles, all using the -06 case, but all in different calibers. I've got most of the smaller ones done, the smallest being the 25-06. There is also a 6mm wildcat called the .240 Gibbs that I've been thinking about, but it may be too much of a good thing. It is so overbore that barrel life is pretty short. Going the other way, the 338-06 and .35 Whelen are on "the list". I have also been researching beyond the Whelen. There is a .41 cal wildcat that is called the .41 Hawk or something like that, but this requires neck reaming deep enough to seat the bullet. Headspacing method also becomes an issue here, as you lose the shoulder. I haven't found a .375 cal version yet, but that doesn't mean one doesn't already exist. Another one I'm pondering is an -06 case, blown out to a straight walled case with a .45 cal bullet stuffed in it, and headspacing on the case mouth. Kind of a .458WM without the belt. I just measured a .458 WM loaded round, and I'm coming up with an outside neck diameter of .485, so this last wouldn't be feasible without reaming the inside of the neck so thin that headspacing on the mouth would be impossible. Or maybe using a .451 diameter pistol bullet? Or even a .430 diameter 44 Mag bullet? Oh, well, playing with guns is fun, and keeps me off the streets!
