Many years ago someone gave me a bunch of "Hyper Velocity" plastic pellets with an in-bedded BB (or small bearing) to try.
I only fired one through my FWB124 and didn't like the harsh shot. The pellet might have gone supersonic but it was almost like dry-firing the springer - NOT GOOD
Had forgotten about those projectiles, might try one in a PCP just for giggles.
View attachment 541285 As a teenager (back in the 60's), I experimented with adding BBs and nails to the .22 caliber pellets for my Crosman 101. Learned then that it was a waste of time and effort as those abortions were way too heavy and nowhere as accurate as normal pellets.
I still think the to be true with the composite pellets being marketed today - expensive, gimmicky and not practical.
Cheers!