Blood trails also depend a lot on where you hit the deer, and whether or not you get a pass-thru.

A hit higher in the body may leave less of a blood trail than one lower in the body. A hit thru both lungs that exits usually leaves a better blood trail than a heart or liver shot because the deer is often bleeding from the mouth.

Having said that, bullet selection can make a difference. I would stay away from Powerbelts, personally. Barnes bullets have a good reputation for pass-thrus and blood trails, I'm kind of surprised you are not getting good trails with them.

For me, surprisingly the bullet that has provided the best blood trails has been the "little" 200 grain Shockwave. It penetrates very well, so I always get pass-thru's, except once on a frontal shot. Most of the deer shot with this have fallen within sight, and the blood trails with this bullet have been better than other bullets I have used. The 250 grain .452 Deep Curl would be a close second for me....