At the time of their introduction - late 70s early 80s - they were seen as powerful but agricultural. The sweet trigger of the Hammerli 400 series they were copies of didn’t carry across. People who liked the military look bought them - there were few military lookalikes and no air soft for that market - but they weren’t relatively cheap like BSAs and Webley compared to the German guns. There were gimmicks like autoloaders and high-level open sights for those looking for novelty. Almost no one used a Jackal or similar for early FT, certainly no one made the prize list running one. The Feinwerkau Sport, the HW35 & 80 and the Original Diana 45 set the standard and the clunky sidelevers simply weren’t as accurate by a long way.
There were issues of barrels not seating properly, allowing a gap between the tap and barrel throat that spoiled accuracy - RustyBuzz knows the story.
By the time the quality ones were produced, the HW80 and more so the almost perfect HW77 were in production. The tap-loading sidelevers, while excellent in themselves, could not compete in terms of performance and were more expensive.
I think the latter models were maybe some of the best taploaders ever made, but at a time when that format was dead. Like most other British airguns of that era they came ten years too late.
Air Arms very sensibly dropped tap-loading and copied the HW77, added useful additional features and the rest is history …
I think the stocks are nice but never liked any of them as they never lived up to the promise of a full-power Hammerli 401, a superb little rifle.