Ok I've decided that I want too use Cast Performance 325gr. LFNGC . But all the data I've found is for plain base not gas check, anyone have any ideas were I can find some accurate data.
Thanks

What load have you been using for the 325 jacketed ones you have been loading?

I suspect that what you want to do ,
is a head scratch-er like I went thru years back with the Roland 460.
With gas checks in my 44 mag I run about the same as I do with lead bullets,don't see the need to abuse my guns.
I have switched totally away from lead,gas checks etc and now coat all my pistol rounds.
Mainly because of the grease streaks [wax]in the dammest places plus my hands.
Went the book routs and bought up to date ones,never found what was necessary in my case so I just did the ladder thingy.

Have you got the bullets yet?

The last two CP HC I bought had some load info inside the box. It was 45/454 and 44 but I don't think any 460.

What powder? The Hodgdon site has a fair amount of data to get you going.

http://www.hodgdonreloading.com/data/pistol

Same bullet I run in my FA 83, .454 Cassull. 20.0 of 2400, 7 1/2 primer and I get 1200 from a 7.5" barrel. Still shoots through an elk at far less than full Cassull velocity.