I am trying to find some load information for use in my Marlin 357. I am using a Saeco 351 200gr cast bullet but I have to use it in 38 special brass and crimp over the front driving band to get the correct O.A.L. Does anyone have any load data for this using Alliant 2400 and AA1680? I am also looking for data using the Oregon Trail 180gr TC in 357 brass using AA1680. Thanks for any help you can give me.

I think that AA1680 is going to be too slow for the limited amount of space available. The heaviest bullet that I have data for in a 38 Spl is a 175 grain cast. The max charge of 2400 is 9.3 grains using a magnum primer for a velocity of 945 fps out of a 6 inch barrel.
The data for a 357 is with a 180 gr. cast bullet. Max charge of 2400 is 12.0 gr for a velocity of 1200 fps out of a 6 inch barrel.
Sorry, I could not dig up anything for a 200 gr. bullet.

Hi:
Alliant has this data. Should be close enough to work with, as the 351 bullet should be close to a round nose in overall length. Proceed with caution, of course.
http://recipes.alliantpowder.com/rg.taf?_function=pistolrevolver&step=2&bulletID=32&cartridgeID=1015&caliber=%2E357&cartridgedescr=Mag%2E&bulletdescr=200%20LRN

Bye
Jack

Send a note to Alliant with your questions. I have found them to be quite responsive. There is an email link on their web site.