The factory spring is very weak and if it has been cut down to much even by adding pre load spacers you have a job to get power out of them. I often get new Expresses doing 10.5 and under and i up rate them, as well as the AR1 kits i now do a stage one kit for these rifles that is not so expensive.
.22 Venom Mach 1 (FAC) 6-25x56 Millett.
.22 Venom Mach 2 Thumbhole 6.5-20x40 Leupold EFR.
.22 Venom Mach 2 Sporter 4-12x40 Leupold.
.177 Venom Vantage 4-16x50.
.177 Venom Daystate 8-32x56 AGS.
.22 Venom Datstate 4-16x56 AGS.
.22 Webley Venom FX2000 6-18x40 Busnel Legend.
.177 Titan MPT by Steve Pope 6-24x40 Tasco.
.177 Pro-Sport 4-16x50.
.22 Webley FX2000 3-9x33 Leupold EFR.
.177 Logan Solo 4-16x50.
.22 HW90 (spring powered) 4-16x50
.22 Gamo Stutzen.
.177 Walther lever action.