Just finished an AR in 300 blk that I plan on taking to South Carolina next month on a hog hunt. As long as you don't try to make a long range shooter out of it, it should be fine. I found a load using 125gr ballistic tips that the gun really likes. I just got some Barnes Tac-TX bullets that are specifically designed for the blackout that I need to shoot this weekend to see how they do.
I would be worried about bullet performance at 300 yards (not enough velocity to expand bullet). Not sure of all manufacture's data but according to Nosler, Ballistic Tips need a minimum velocity of 1800 fps for expansion. With the 300blk, it does not take a lot of distance to drop to that velocity. However, Barnes is claiming full expansion and 20" of penetration at 300 yards with their Tac TX round.
I would go with the 125 grain Nosler Ballistic Tip for Pa whitetails. You will get good penetration and expansion at 300 blkout speeds. A lot of guys also use 110 grain Barnes and even the 110 Vmax has it's fans.
Here is my blackout build. All Palmetto State Armory
Tried flip up offset sites on this one.
Here are the two bullets I've tried so far, the 125 nosler and 110 barnes next to a 230gr bullet I cast but have not tried yet. This 4 shot 100yd. group (didn't load five for some reason) was with the noslers and lil-gun powder. H110 was not as tight.
With the lighter bullets, I think it would make an excellent deer cartridge. I use a 25 TCU with 85gr ballistic tips, a 223 necked up to 25 cal. for deer. I have killed deer from 30 yards to 228 yards with it. All deer dropped on the spot or within 25 yards.