Powerbelts have killed many, many deer and have their pros and cons. Personally, I think they are a bit expensive for what you are getting.
Pros: Easy to load, wide availability, usually pretty accurate
Cons: Expensive (at least where I shop), velocity limitations, questionable terminal performance, especially with lighter weights
You should be okay with your 295's, but please don't use 150 grains of powder. 100 grains of pellets or 80 grains loose powder should be a max load for that bullet.