Hi guys,
I'm new to the forum and just caught up with this discussion. I have a 590 that I have fired various types of shells through. Using the Mossberg pistol grip, I found it very difficult to control the weapon, especially with 3" shells. Using Magnums, I couldn't even hold onto it with my left hand, it would jump out every time. At a recent gun show, I picked up some Estate Catridge Inc. low-recoil SWAT shells that have about half the charge of a regular shell. I picked up both OO and OOO buck to test out with my pistol grip. These are intended for use by SWAT entry teams when the expected engagement ranges will be quite close - similar to the situation you'd be in if, God forbid, you had to defend your house.
I also ordered a Speedfeed IV Tactical Stock from Airzona Gun Runners (their prices were as much as $20 cheaper than other online dealers). This is a solid stock with pistol grip. I haven't had a chance to use it yet, but it should provide much better control for high-powered loads.
Dave in Kentucky