I built one of those jigs, but don't use it now. A gunsmith friend does it a different way and it's what I do now. Maybe some of you guys would comment about it. Not sure how it would work for cast, but drop it does work just fine. He lays the gun on a table with the trigger guard back, off the table. He puts a couple bags of shot [ 50#s ] on the muzzles. Two heat lamps and a rag soaked in some type of oil wrapped tightly around the wrist. One bag of shot is put on the butt. He then puts a stop of some sort the distance away he wants the stock to move. He then goes to some other gunsmithing activity, or reloading, and keeps a eye on the progress being made. He hasn't bent a lot of stocks, but has never broken one. He claims if it doesn't want to bend, it won't. I've had to put two bags on the butt on a couple, but also haven't had a problem with breaking stocks. It's pretty simple and the only out lay is the two heat lamps and light fixtures which are pretty cheap. I just thought I'd throw this out there. Any thoughts ?