I am using the 250 grain shockwaves... I have a new TC Omega, but both my father (TC Encore) and friend (remington) have the same problem. Basically you are cutting groves in the plastic while you push it through the rifling, so there is where the problem exists.

On the other hand My friend had a gun (I think it was a Knight) that was .504 and was significantly easier to load the shockwaves.

I will be using powerbelts from now on, range and accuracy are more than sufficient for my hunting needs.