I'm close to settling on 102gr of RL22 under Barnes banded solids and TSX. About 2400fps, same POI and 1 moa groups. As near as I can tell this may be a shade hotter than standard, but not up to max in the manuals. I'm just soliciting comments regarding pressures. It seems to me that my P17 action should be well up to these loads, the pressures should be reasonable. Do these seem kosher to people here with far more big bore experience than me?

I don't think you're hot rodding the .416 Rigby at all. Is a pretty low pressure cartridge with lots of overhead room in a modern rifle if you use good brass.

I personally prefer 350 gr TSXs at 2700 fps

Marty, what bullet weight??

I agree with mstarling.

Sorry, 400gr.

Marty

I had to opt for 90 grains IMR 4831 for RHINO monometal solids in my CZ 550 due to the ogive / shape. Had to seat them WAY in to chamber properly. Don't know about the Barnes solids but the manual shows you'd be good and since RHINOs and Barnes are similar I wouldn't be concerned, especially since you know the speed. (I get 2360 fps and the manual says 91 grains IMR 4831 for the same speed.)

I show a max load for RL-22 is 104 grains with 400 grainers. With banded bullets you ought to have even more cushion pressure-wise, methinks.

I'm loading for it in a ZKK-602 (not much different than the 550) and loading 103 grs. of H-4831SC with the Hornady 400 gr. SP. That's about all I can take. Jack O'Connor's favorite load was 107 grs. with a 400 gr. bullet. I don't know how RL-22 and H-4831SC compare.