cascadedad/
philnie
Please remember I am not an expert, but if I were you two I would develope a load using T7-3f. Triple Seven requires more heat than the pyro's to start. I would suggest the 3f because it is easier to ignite and on some cold, damp Washington morning that is going to make a big difference since you are limited to #11 caps. You have to keep everything dry and it needs to ignite now! when you pull the trigger. Shooting now and through the summer will not give you a good indication of what your gun will do when it really is cold. In fact your point of impact between the warm weather now and the cold weather later may change a bit... Sabots are really suseptible to heat.
Because of the area that you hunt in I still would suggest the 260 vs the 310. Velocity and accuracy being the key... When you look at the hunting regulations for Washington you will understand what I am about to say about hunting elk. Getting an elk permit in Washington is not automatic and it is not easy... often the seasons do not even coincide. You probably will not be able to do a darn thing about any elk you see. Set up for deer and when you get a chance change to an elk load, although the 260 will job on elk also - if it gets penetration.
I am looking for my range log book but those velocities I got for you aff the Wholesale hunter site a low for what you will actually shoot with T7... I just had the log the other night now I can not find it...Found it I actually put it back with the chronograph...
With 110 grains of T7-2f shooting an Omega I was getting:
1880 fps
1877 fps
1854 fps
That is really getting along for a 260 grain bullet.
Here is ballistic chart for a 250 grain Gold Dot pushed by 100 grains of T7-2f