Sounds like you did alright with measuring. The shorter barrel won't hurt you in terms of twist. It's tough to add velocity, and gain stability. JBM has an online stability calculator that's easy to use to help sorting stability issues between bullets.
If what cartridge you're using has been mentioned I missed it.
Butterbean is a high velocity guy, I'm historically a bigger bullet fan, and when changing bullet weights it's usually 25-30 grains at a time. He says use the 152, but he generally uses lighter faster, I like the 174 grains Hammer Hunters in my .30 calibers, which my minimum in .308's used to be 200 grains. Whose right? Split the difference, and use a 166 Hammer Hunter?
Hammer's are slowly changing how I view terminal performance. A lighter bullet that has consistent performance can work very well. The 181's likely will work fine for you, but a little more stability helps keep the bullet square to the target, and in my opinion helps with expansion, and straight line penetration.
Good Luck!