Do I have to change anything.

[Frank38]

I have been loading 3 grains of Bullseye under cast 100 grain SWC in my 357 Ruger Security 6. in 38 Special cases.

Will I have to change anything if I use 357 cases, as I have been given 200 Starline new brass cases.

[Scharfschuetze]

No, but many reloaders will up the Bullseye chage by .2 grains or so to compensate for the larger volume of the 357 case over the 38 Special. If you use the same charge in both cases, you'll just loose a little velocity in the 357 cases. No big deal and your targets will not notice a thing.

I do this with my 148 grain WC loads. From the classic 2.7 grains in the 38 to 3.0 in the 357 and I get about the same velocity (750 fps or so depending on the barrel) by doing so.

[dverna]

You will get less pressure and velocity in the larger case.

[Frank38]

I've been seating the bullet tip flush with the case mouth. I'll increase the powder a little and leave the seating the same.