Actually, the mainspring of the Diana 48/52 sidelevers is also held in place by these two pins only, and their unrestricted versions are pretty strong, about 18 - 19 ftlbs in .177.
However, the spring preload of the Model 50 is much higher than that of the 48/52.
Cheers,
-Topi
I think i will go for a standard airsporter spring for my rifle and see how it goes.
Sabre