How does it adapt to the variance? All my airsoft ARs vary significantly in the sizing of their buffer tubes; a stock that's tight on a TM will wobble like crazy on an Avalon/VFC.
I'm also unsure why you'd need a shim for commercial spec buffer tubes? Mil spec tubes are the thinner ones.
And is there a site selling them that ships outside the US? Or do you have to contact HolsterOps directly? Attempting to go through their checkout, they don't allow any country but US to be selected for the address.