Clip-on wheel weights plus 1.5 or 2 % tin.
For rifle approximately 92-6-2, but will caveat that my rifle loads are all in the 1500-1600 fps range.
Similar to yourself, I switched to this alloy when I was able to buy about 1,000 lbs of pure lead. I only did that after reading how it could be used for something other than muzzle loaders here on this website. Makes me sick to think of the pure lead I turned down prior to that. Previous to this I used nothing but clip on wheel weights with a few stick-on weights added just to use them up. Everything I've ever cast has been air-cooled also. My method for handling higher velocity is gas checks. Since that only applies to rifles for me, the cost of a gas check isn't significant because of the quantity needed. All my rifle hunting loads are somewhere between 2,000 and 2,100 ft/sec.
BP | Bronze Point | IMR | Improved Military Rifle | PTD | Pointed |
BR | Bench Rest | M | Magnum | RN | Round Nose |
BT | Boat Tail | PL | Power-Lokt | SP | Soft Point |
C | Compressed Charge | PR | Primer | SPCL | Soft Point "Core-Lokt" |
HP | Hollow Point | PSPCL | Pointed Soft Point "Core Lokt" | C.O.L. | Cartridge Overall Length |
PSP | Pointed Soft Point | Spz | Spitzer Point | SBT | Spitzer Boat Tail |
LRN | Lead Round Nose | LWC | Lead Wad Cutter | LSWC | Lead Semi Wad Cutter |
GC | Gas Check |