A ground squirrel was sighted in my wife's garden. This means I need to be ready NOW (otherwise my airgun rationale and budget as garden defender could be at risk). This would most likely be a quick offhand shot and I'm still working on that with that big pistol. So a shoulder stock would help.I made a small block to clamp to the grip using the existing internal cylinder. I contoured it to the grip with a sanding drum. It looks like something around a 14mm radius. I had a HDPE (cutting board type material) bar from some other experiments that attaches to the block with a step index. The custom butt pad works surprisingly well and is comfortable. The assembly is rigid and works well.Long term I will probably do some upgrades, but right now it is Game On squirrel!