Glad you found a good load, Bob. I am assuming your gun is rifled.

I'm also finding out, somewhat to my dismay, just how much different 'holds' can effect impacts of a double. I thought I was holding properly using the bag under my left hand, just as I would hold when shooting offhand, but the gun certainly shoots better and with less dispersion offhand, than off bags. I can consistantly hit better offhand, than my bench groups indicate I should be able to.

As rigbymaster indicated, follow through is very important with low velocity firearms - this means the hold must be the same shot to shot, so the recoil and therefore barrel kick is the same shot to shot. The more recoil, the more exacting must be the consistancy of everything involved, form loading to holding and shooting.