hulley, if you're gonna use cast bullets frequently, you're probably going to need a Lyman manual, either the 49th edition, the Pistol & Revolver III or their dedicated casting and loading guide.
Unfortunately, in the newer data, the closest bullet weight above 140 is 150 grs. and they didn't load with Unique. Personally, I've never cared much for Unique in .357 Magnum loads and there are better powders that are just as universal in application like True Blue that's a very dense spherical that meters night and day better than flake powders. Plus, Ramshot has excellent load data that is pressure tested.
In the load data that 44 AMP listed from the Lyman 45th, the bullet used was a full wadcutter and data for that bullet would be higher pressure than with the bullet your using because the wadcutter has a much longer bearing surface so it's load range will be a bit more limited. Even still, the data from the 45th was reduced in my 46th where no load exceeds 40,700 CUP. Different pressure testing method, but with the current SAAMI limit of 35,000 PSI, they will run higher than that when measured in the CUP system and because of that, I'll list data for the same #358495 141 gr. Wadcutter:
Unique Start: 5.8 grs. 960 FPS @ 14,600 CUP.
Max: 7.9 grs. 1289 FPS @ 40,300 CUP.
2400 Start: 10.5 grs. 1015 FPS @ 18,200 CUP.
Max: 14.6 grs. 1376 FPS @ 39,700 CUP.
With either of these two powders, loads are gonna be fairly dirty until you get at least over the mid-charge level and start working towards top-end loads. Becasue of the Wadcutter bullet type used for these loads, the load range for a 140 gr. TCFP should run a bit higher, but if your after good general use plinking loads, this data will be fine for that. The powder I'd be using for this application would be Ramshot True Blue and again, nobody gives as broad a range of load data as Western Powder Co. who owns both Ramshot and Accurate powders. AA#5 could also be used and AA#7 is even better for mid to upper range .357 Magnum loads although I still prefer True Blue for that application. Ramshot used the LaserCast 140 in their .38 Sp. and .38 Sp.+P load data, btw.
Unfortunately, in the newer data, the closest bullet weight above 140 is 150 grs. and they didn't load with Unique. Personally, I've never cared much for Unique in .357 Magnum loads and there are better powders that are just as universal in application like True Blue that's a very dense spherical that meters night and day better than flake powders. Plus, Ramshot has excellent load data that is pressure tested.
In the load data that 44 AMP listed from the Lyman 45th, the bullet used was a full wadcutter and data for that bullet would be higher pressure than with the bullet your using because the wadcutter has a much longer bearing surface so it's load range will be a bit more limited. Even still, the data from the 45th was reduced in my 46th where no load exceeds 40,700 CUP. Different pressure testing method, but with the current SAAMI limit of 35,000 PSI, they will run higher than that when measured in the CUP system and because of that, I'll list data for the same #358495 141 gr. Wadcutter:
Unique Start: 5.8 grs. 960 FPS @ 14,600 CUP.
Max: 7.9 grs. 1289 FPS @ 40,300 CUP.
2400 Start: 10.5 grs. 1015 FPS @ 18,200 CUP.
Max: 14.6 grs. 1376 FPS @ 39,700 CUP.
With either of these two powders, loads are gonna be fairly dirty until you get at least over the mid-charge level and start working towards top-end loads. Becasue of the Wadcutter bullet type used for these loads, the load range for a 140 gr. TCFP should run a bit higher, but if your after good general use plinking loads, this data will be fine for that. The powder I'd be using for this application would be Ramshot True Blue and again, nobody gives as broad a range of load data as Western Powder Co. who owns both Ramshot and Accurate powders. AA#5 could also be used and AA#7 is even better for mid to upper range .357 Magnum loads although I still prefer True Blue for that application. Ramshot used the LaserCast 140 in their .38 Sp. and .38 Sp.+P load data, btw.
