Zachary,
Nosler has never, to my knowledge, reccomended any Balistic Tip bullets in 30 cal or smaller as an elk bullet. The 338 Balistic Tip is recognized as a dependable elk getter.
I know several people that use the 25, 270, and 284 Balistic Tips as deer bullets with great success, even in high velocity cartridges like the 25-06, 270 Win, and 7MM RM. I have killed several deer with the 30 cal 165 gr Balistic Tip in my 30-06 at 2900 fps MV. Only once did I fail to achieve a one shot kill with this bullet, and that was only the fault of the marksman.
I have only seen the 165 gr Balistic Tip exit a deer on neck or head shots. On any chest shots I have taken, the bullet has fragmented inside the deer, totally destroying the heart, lungs, and (depending on the angle of the shot) possibly the liver and diaphram. While any of these organs makes for a lethal shot. A deer will never travel very far if you manage to destroy them in combination.
On the other hand, a premium bullet can not make up for poor shot placement. A gut shot deer is still gut shot even with the best bullet money can buy.
Judging from the performance in the field which I have witnessed and experienced, I would not hesitate to use the heavier Balistic Tip bullets in any caliber above 243 for deer hunting. But I definitely want a less frangible bullet when elk hunting.
One of the best guides to the proper use of a bullet is in the manufacturers' own loading manuals. Most of them will give a guide as to the weight of game and muzzle velocity the bullet was designed for. Many Balistic Tip bullets were designed as varmint bullets and are therefor very frangible. These are usually the lightest weight for caliber, and are identified as such in the Nosler manual.