If the bullet killed the deer than it did what it was supposed to do. Bullets react differently depending on what they hit. There is a major difference between hitting soft tissue and hard bone in the way the bullet will function. Personally I am not a fan of a lot of the new bullets they are putting out. Nosler Partitions have been my go to bullet for years and I see no reason to try any of the "ballistic tip" type bullets.
In reality there is no such thing as a "brush gun". Any caliber can and will deflect if it hits an object between you and the intended target.
True words in the above comment. No such thing as a brush gun that cannot be deflected. Once in South Africa I was playing with the rifle a PH buddy of mine carries. It was a 450 Rigby firing a 500 gr bullet with more than 6000 ft lbs of energy. My buddy does some elephant culling in Kruger and uses this rifle. I took a shot at a blue wildebeest cow that had been injured and they wanted put down and the bullet hit a twig about the size of a pencil and deflected so badly that the animal was missed completely. Second round dropped her on her chin. If a 45 caliber rifle with 3 tons of energy isn't a brush buster then nothing is.
Just sayin....