I am a V-Mach approved tuner, i also supply my own tuning kit for SMK XS19,XS20,XS36/2 XS38 and XS208 models , i now sell these kits under the name ARC Tuning. These kits are not V-Mach kits, the XS 19 spring kit consists of a steel piston liner, a Titan spring with a spring guide and top hat and power adjustment washers. With the kit you get a small bar to tap out the pin holding the cylinder end and a tool to remove the standard spring guide. This kit is £44.00 i can also supply piston seals, barrel seals and small tubs of moly grease. My own .22 XS19 will fire a Air Arms Field pellet at 11.70 ft lbs and can be cocked with my little finger.
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.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.