Built one (20 VT) on my rear grip Savage left hand repeater action with a single shot follower. 16" barrel. A little too much recoil (if you want to call it that) for what I was after. Final goal was to be able to see my hits thru the scope. Got close to my initial goal but not close enough for my liking.
Switched to the "short" version. (20 VT with the shoulder pushed back .200") Got even closer but still not what I was really after. 100 yards I could "almost" see the holes forming. Anything out to around 150 yards and you could see your hits. That was enough time for the rig to settle back down from the recoil jump. Straight pipe isn't enough weight to get the job done. Next step in a "20 TCM". That should get me what I want.
Even built one in the 17 VHA. Still havn't worked out all the kinks or got enough load data yet.