I think the best bet would be to try to find someone to weigh them and see.

That being said to go along with the above post, I've found the Powerbelts to be easy to load, and I've also found them to be very accurate and to shoot extremely well. I used them for a couple of years, but I found the performance on deer to be horrible and they don't usually exit, and they don't usually leave a blood trail. I've since switched bullets and am much happier. I've got a friend that still uses the Powerbelts, and he constantly is complaining about the same thing I didn't like about them. He refuses to change bullets though as the shop that sold him his gun told him not to shoot anything else in it as the gun was made for the Powerbelts. He then had another guy tell him that his only shot Powerbelts well. So he chooses to listen to the bull those guys told him instead of shoot a bullet that performs well.