Rob - First off, welcome to the forum. Lots of guys here with the same interests and lots of knowledge.
Like you, I'm addicted to PD and ground squirrel shooting, and try to get out in the field at least 30 days a year sniping the little buggers with various rifles and calibers. I've found the .20 calibers to be outstanding in this regard, especially for work under 600 yards.
As for taking videos of flying rats, here's what a good friend of mine here from SA uses to capture great "launch" vids using a neat bracket that attaches to the scope, and also holds the camera. Here's a couple of shots to illustrate the device:
Simple, highly effective, and the best device I've seen to date for accomplishing this hard to do task:
The videos this little system produces are quite outstanding; works very well indeed. Hope this helps in the quest for saving field fun for later.
