Airmasters and Venom were the two big ‘tuners and modifiers’ back in the day. Venom sold good kits as well. But today they are a dozen or more excellent tuners and modifiers offering bespoke solutions to improving a springer, some of them far more radical than Venom. The knowledge and skill is more widespread and diverse now so people can go after particular solutions. True there are only a few stock makers to choose from but CS offers a good range at a low price to the individual wanting to get a better fit. There’s fewer people willing to spend a fortune on a full custom springer since the PCPs arrived. There are several good spring guide kits available and several different aftermarket brands of piston and breech seal. It’s a bit like the market for airguns in the U.K. was once completely covered by Webley and BSA; there are many more options today.
Venom were pathfinders and now there’s a whole complex market.
I think their main legacy are the innovations included in the Air Arms springers, the TX and the ProSport, which basically offer a Venom type tune out of the box. Apart from all the old Venom custom rifles that drive the collectors into a frenzy ...