I just spent a while modifying mine so it has a moderator and is an inch shorter overall than the standard model. I swapped the seal, spring and guides. Chopped the barrel and cocking lever by 6". Fitted a small moderator and extended a lower cocking lever to almost reach the end of the moderator. It is now doing 11ftlb but is pellet fussy. It works well with standard .22 JSBs and Hades- 3/4" group at 22m and 6fps variation in velocity. It might improve a bit if I crown the end of the barrel properly instead of just spinning a countersink bit in the end to smooth it off.

It is not bad as a tiny, light springer.

In terms of size, HW57s were competing with Diana 52 carbines. The Diana did everything better but was heavier.

BB