Mossie
Swiss is supposed to give another 100-170 f.p.s. from the same charge load. My guns max. is 120 grains of 2f and 110 grains of 3f. I would not push it beyond that.
I would bet that it will quite a bit more than 100-170 FPS... In fact if you load up 100 grains of 2f - I would bet you will be shooting a 250 close to 1800fps and a 300 near 1700.
I have no personal experiance with Swiss other than what Cdad has told me and information I have read on the net - so only you will know for sure... but I'll bet - it will exceed you estimates...
Here check this out....
