The big brass cases is from Rocky Mountain Cartridge and is loaded with a cast slug of pure lead weighing 720 grains.
The bullet mold is from NEI and is a cut down mold for a 900-grain bullet for a .600 Nitro Express. My usual plinking load uses a FED 209 primer and AA5744 for a velocity of 1,000 fps. A better hunting load is to hollow point the slugs with a 3/8-inch drill on a lathe reducing the weight to 550 grains (1-1/4 oz). With 60 grains of 5744 the velocity is 1,330 fps in my TCR-87 with a 23-inch barrel. The barrel on my gun has the outside contour of a 10-ga magnum so with a 20-gauge bore is probably much stronger than most 20-gauge barrels, and the action is strong enough for a .416 Rem Mag. My gun is good for 20,000 psi so I am not concerned about pressure from this load. However, I contacted a technician at accurate arms to confirm my pressure estimate for this load. I told him that the length of the powder column was about the same as a .45-90 loaded with a 300-grain bullet and that a .45 caliber 300-grain bullet and a 550-grain .62 caliber bullet have the same sectional density. Therefore, at the same velocities the .45-90 with a 300-grain bullet and my 20-gauge with the 550-grain bullet would have the same pressure and he agreed. He said the pressure would be about 12,000 psi. I got the velocity up to over 1,500 psi but recoil was higher and I wanted a load that would be very conservative in my gun. Since my barrel has a 1-in-24 twist and can stabilize the 700-grain bullets, I think a 1-in-28 twist would be OK for the 550-grain hollow points. At 100 meters this load in my TCR-87 put 4 of 5 shots in about 2-1/2 inches. I use sabot slugs for deer hunting but shot one deer with the 700 grain load and one deer with the 550-grain hollow point load. Both died. I am thinking about loading sabot bullets in the brass cases. I got bullets and sabots from Ballistic Products in Minnesota. The sabots are slightly too large to fit in the necks of my cases. I pulled the sabots and bullets from Hornaday's 20-gauge SST loads and it appears they will fit, but that would not be a money saving process. I was thinking that I could substitute Hornaday 300-grain .45 caliber slugs for the 250-grain slugs in their SST sabots for a better balistic coeficient and increase the velocity to about 2,200 fps for even better long range performance. The brass cases have more powder capacity. However, I would be experimenting where there may not be any good pressure data to correlate from. Also, the 550-grain hollow points were not of pure lead, but a harder mixture. They seemed to lead the barrel where as my pure lead 700-grain slugs do not lead the barrel. I guess the harder mixture does not obturate to fill the barrel well at such a low pressure, so there must be some gas leakage past the bullet. Also, the hollow point broke apart on the deer I killed with it. However, the deer was bedded down and I shot it in the front of the chest and the slug went through several inches of spinal column. I thought the bullet seemed brittel rather than ductile like a softer lead.
