I have built several XP-100 pistols, using the Kelbly (formerly Lee Six) rear grip stocks. They are great. My personal ground hog/prairie dog pistol is a 15" barrel 223 Culver. That is a 223 with a 35 degree shoulder. I have dispatched hundreds of varmints with this outfit since building it in 1994. With the 15" HV barrel it weighs just short of 14 Lbs. I have another stock in the shop now that i asked Jim to make as heavy as possible. It weighs 12 Lbs. 12 Oz. I'm planning a 6MM DJ ( .070" longer, at the shoulder, BR) with an 8 twist barrel. The stocks are a little rough on the exterior but very well made.