Hgunner
You're not being a pest at all.
Sorry but I don't have more data with the 250 XTP. When I shot that one with 28.0 gr. of 4227 it was one of those few times that the first load tried did so well I did not mess with any others.
I one time did an experiment with several different bullets, all loaded with the same powder charge...28.0 4227 and recorded the velocities and accuracy I got with each. I used several different 300 gr. bullets, and all of the jacketed went right at or around 1400 fps. Extreme spreads with each was very close as well, and all were low.
I have not hunted with the 300 XTP Mag. I have read a lot of opinions on the impact velocity needed to get expansion, and don't know what to believe is true. You can search some other forums for opinions on this bullet, and seems it is a love or hate. Some say it acts as a solid, others seem to think it expands. In my very less than expert opinion I would use that bullet for big heavy game, and would use the regular XTP on animals like white tails.I did shoot a deer with a 300 XTP (non mag) but it was from a 45 Colt and was loaded to 1350 fps. Performance was near perfect. Deer was shot at 30 yards behind the shoulder double lung, and while I did not recover the bullet there was strong evidence of expansion and the deer was an easy recovery.
I agree also with the comments on using Alliant 2400. It has been a great powder for me, and I still use lots of it. I just don't use it in my 454's. I have, but found extreme spreads were higher. It is also the only powder that I ever got a load in my FA gun that had sticky extraction. It is good powder, just not working as well for me as 4227. I have also been told that 4227 is easier on forcing cones, and with all the forcing cone problems I have had I look for anyway to avoid them.
I looked at my older 50th Anniversary Sierra manual, and there are some reduced loads with their 240 grain bullet. That manual also has some more reduced loads with their 300 gr bullet too.
When you say you are looking for a load to hunt "from deer to elk" in my opinion finding the right jacketed bullet for both is difficult. If you want one load that is good for both, I would really look to the lead bullets. You mentioned the cast performance bullet, and I think that is a good choice. You will shoot through any deer from any angle, and believe it will do the same on elk. I have had some great results with the Cast Performance 335 gr WLNGC bullet.
Some loads with that bullet and 4227 powder:
25.5 gr. 1247 fps ES 21
27.0 gr. 1335 fps ES 53
28.0 gr 1400 fps ES 9
These were all fired with a 6" barrel gun. My 7.5" does just a shade under 1500 fps with 28.0 grains. I did not really believe that one, so shot the same load on another day, and my average velocity was within 4 fps from the previous.
I am planning a bear hunt this fall and plan to use my 454. The load I have settled on is the 300 grain RCBS semi wadcutter gas check bullet. I am loading it with 28.0 gr. 4227 and depending on barrel length get 1350 to 1450 fps. It is extremely accurate in all of my guns. We shot it in a friend's 454 that is also going on the hunt and his scoped gun is shooting the proverbial "one ragged hole" group at 50 yards. He had a 2" group at 100. I have tried this load in 4 different guns and have not found one yet that it does not shoot well in. Not a top end load by any means, but enough to do the job on about anything I will ever shoot.
For what you are looking for, I think a lead bullet and 27 to 28 gr. of 4227 might be just the ticket.
Good Luck
Dan