Got any reloading ideas for a T/C?

[KillaB]

First post on the forum, been reading for a while. I was hoping for specific info from other shooters that have a similar setup as me. I have the 300 Whisper in a T/C Custom Shop barrel, 16.25 inch barrel with 1 in 10” twist. I am looking to shoot supersonic for whitetail deer. With the Nosler Ballistic Tips, I can’t seat the 125 gr. out far enough in the T/C barrel (throat too long?) but can seat the 150 gr. Also, I’m shooting H110 and have H4227 (but have considered other powders that are recommended) in .223 brass bought from SSK.
Last thought, I did load up Sierra 135 gr. Single shot pistol bullets for hunting last year. Missed a doe and found the bullet in the dirt; unexpanded with the lead tip knocked off. Not impressed with that. Bottom line: is the 150 gr. too heavy and slow for hunting? Any suggestions on bullets or powders are appreciated!