I want to use Alliant 2400 or Winchester 296 with 50gr. SP and Rem 7 1/2 SR primers. Anyone have powder amount suggestions? Thanks.

Nothing I have lists those powders. I checked the Lee manual, the Alliant free manual, and Steve's Pages.

Neither of those powders are suitable for your load, if you are intending on using it in a rifle.

I would suggest you use:
Benchmark From 22.5 grains to 24.0 grains
Remington 7-1/2 Primer


If you are using it in a handgun, then:
2400 From 11.9 grains to 16.2 grains
Remington 7-1/2 Primer

But you would be better off with:
IMR-4198 From 17.5 grains to 20.5 grains
Remington 7-1/2 Primer

In my benchrest rifle, 19.6 grains of IMR 4198 with a 52 gr bullet gave best accuracy. But, in my sporter, RL-7 works best with a 50 gr bullet. 4198 doesn't work well in that rifle. It all depends on what your rifle likes.
Don

I'm really not looking for the most accurate at this time. I just want to use what I already have safely.

Well, the two powders you asked about are basically pistol powders. And you were asking about a rifle cartridge.

with the 55gr fmj 13.5 gr. 2400, 2600 fps

same bullet 15gr. 2400, 2750fps

46gr. hprn, 16gr. 2400, 3000fps, dirty, not max.

Non of these loadings had great repeatability. roger