Quote Originally Posted by Shed tuner View Post
yes.. if the gun's action slides backwards at say 20fps, then you will get a reading 20 fps lower. One could argue that is the real reading - ie that's the velocity the rifle discharges a shot at.

but you seem to have got a 5 fps variance with the action locked forwwards - which makes sense - but a much bigger one with the scope fitted - which doesn't.
Hi Jon

When I did accelerometer based tests on my TX200SR Mk1; I found that the action was travelling forwards (lunge or surge phase) at pellet exit was 1.5 fps so the pellet velocity measured in free space beyond the muzzle would be 1.5fps high - well within the usual pellet too pellet spread methinks!

That was one helluva nice shooting rifle though! Was a casualty of one of my clearouts!

atvb
David