nralifer

Chronograph Superformance load. Used 59gr , 215m primers,.270 Win new unfired brass in Win model.70 push feed with 22 in barrel, and got 3150 fps from a Barnes Triple Shock 130 gr bullet. No pressure signs or case head expansion. Ambient temp 74 degrees F. Case OAL was 3.202 in.

I would consider leaving the gun as is, finding a used Stevens/Savage short action, rebarrel it to a 260 Remington using the best barrel you can afford and drop it into a Hogue pillar bedded stock. Brass can be hard to find, but you could neck down 7mm-08 brass or neck up .243 brass. The new powders, Superformance, CFE 223 and Leverevolution could make that .260 sing. Changing barrels is a snap in Savage type actions.

I've tried to see if crimping affected group size, and to be honest, I did not see a consistent effect. I like to crimp using a Lee factory crimp die. It is a collet type that maintains bullet alignment during crimping.

One thing that will likely improve accuracy of any bullet/powder combination is a competition bullet seater die. Cuts down on flyers in groups because it maintains better bullet/cartridge alignment

To develop a load one can use the relative burn rate chart on the Hodgdon web site. Superformance is listed as slower burning than H4831. I have started out with Superformance loads that are 2 grains less than those listed for H4831 and looked for overpressure signs such as flat primers, trouble extracting the case or expansion of the case head. I also have a chronograph which helps. In the 330 Dakota for a 225 grain TTSX bullet, Hodgdon lists 84 grains of H4831. I used 82 grains of Superformance and got 3006 fps with no pressure signs at all. Be sure to follow case length and overall length recommendations for the cartridge/bullet combination. Prior to attempting the above, I studied the available load data from various sources to be sure that powders listed as faster burning than H4831, as expected, used smaller charges than H4831, and vice versa for slower burning powders. This tells me that the burn rate chart accurately predicts the relative behavior of the powders in the cartridge in question. For the .270, today I tested 130 grain TSX bullet in once fired full length sized Federal brass using 58 gr of Superformance and Federal 215M primers. There was no head expansion, and primer flattening was no different than seen on factory ammo, and there was no problem with extraction. Have not chronographed this load yet. Too much wind today. All my load development for this powder is in modern bolt action rifles. Although this experimenting is fun, one does it at his/her own risk. If one wants to try this, be sure to have reliable published load data for the cartridge in question and check all the numbers yourself. Do not trust my numbers. Remember that in hot weather chamber pressures will likely be higher than in cold weather. The temp today was 40 degrees F. I would not recommend ever exceeding the listed H4831 charge.