Clear Winners were borderline unshootable for the recoil, the Sonics left you with no such qualms.About the same time these pink Express HV cartridges were about there was also a green Gamebore cartridge called "Super XLR" cam paced in a green box. They were not the same as the current xlr and were priced about £77 a thousand - i used these combined with Gamebore Clear Winner for any slightly longer / harder targets.
I also used to quite like the Victory cartridges - Compact, Challenger and finally Sonic's. Seem to remember these were sensible money too. They sponsored a lot of shooters for a while - they were all kitted out in their maroon skeet vests?