The Xshot Longshot is horrendously overbarreled if you add a longer barrel without a 250+ fps spring. This fits an adjustable SCAR into the collet so the barrel can be kept to a minimum on sub 250fps setups while maintaining accuracy.
Tensioner cap version requires 3 short m3 screws.
The author remixed this model.
Modified remnant scar to fit in the longshot collet and act as the barrel retention