Did you ever notice that when you shoot your big boomer from a standing position that the recoil seems a lot milder than at a bench? Folks who spend a lot of time shooting these type of guns have a stand-up bench. That way, the gun shoots just as it would when you are using it in the field. You have the same mass and movement behind the gun as you would have when shooting it "for serious'. There will be no POI change to take account for. Heck, last August, I shot a big Cape Buffalo at a really close distance and I don't think that I even heard the gun fire. I know a guy who does a lot of testing and load development with BIG double rifles. He has a stand-up bench for this testing. I actually have a chunk of Sorbothane that is about 3/4" thick that I use on "Kicking" guns up to my .375 H&H and from there on I use a stand-up rest. Take a look in Graeme Wright's book "Shooting the British Double Rifle". He covers the subject of shooting rests and sleds very well.
Just a thought,
Craig
Just a thought,
Craig