Got done loading up some rounds to fire form. My cartridge is a .280 GNR which is a wildcat based on the .405 Winchester parent cartridge. I've read plenty on how to neck up/down cartridges and done quite a few based on the .30-06 cartridge but I never did have to really fire form any rounds.
The .280 GNR is a Gary Reeder cartridge designed for use in Encore frames. My barrel is a 17" pistol barrel of course about 2" of that is just muzzle brake. Obviously it is a 7mm cartridge with an "Improved" shoulder. This cartridge is supposed to equal .280 AI performance out of a pistol barrel. The guy I got it from had been getting 2900+ fps with 140 grain bullets.
My steps for getting the .405 parent case necked down to 7mm was this. I first ran the virgin cases through my .35 Whelen die and then my 8mm-06 die with decapping rods removed. I was hoping to keep from work hardening the necks by taking them down in steps. Then to get them down to 7mm I ran them through my .280 Rem die and seated the bullets with my GNR seating die. I did try my GNR sizing die, but was worried that the cartridge might not chamber easily since it didn't resize much of the neck.
I did get some cartridges that were already fire formed so I loaded them up as well with two different 140 grain bullets. I loaded the Nosler BT to where the boat tail was just below the base of the neck. The other bullet is some bulk stuff I bought at a gun show with a cannelure and I loaded to it thus the difference in length. However as long as the Nosler bullets are they still chamber in the barrel without hitting the lands.
Can't wait to see what I can do with this cartridge!
The .280 GNR is a Gary Reeder cartridge designed for use in Encore frames. My barrel is a 17" pistol barrel of course about 2" of that is just muzzle brake. Obviously it is a 7mm cartridge with an "Improved" shoulder. This cartridge is supposed to equal .280 AI performance out of a pistol barrel. The guy I got it from had been getting 2900+ fps with 140 grain bullets.
My steps for getting the .405 parent case necked down to 7mm was this. I first ran the virgin cases through my .35 Whelen die and then my 8mm-06 die with decapping rods removed. I was hoping to keep from work hardening the necks by taking them down in steps. Then to get them down to 7mm I ran them through my .280 Rem die and seated the bullets with my GNR seating die. I did try my GNR sizing die, but was worried that the cartridge might not chamber easily since it didn't resize much of the neck.
I did get some cartridges that were already fire formed so I loaded them up as well with two different 140 grain bullets. I loaded the Nosler BT to where the boat tail was just below the base of the neck. The other bullet is some bulk stuff I bought at a gun show with a cannelure and I loaded to it thus the difference in length. However as long as the Nosler bullets are they still chamber in the barrel without hitting the lands.
Can't wait to see what I can do with this cartridge!
