I load 180 gr XTPs with 7.9 gr of LongShot and CCI 550 primers. I have chronographed the 180 gr at 1056 ft/s from a 3.5" barrel, 1108 from a 4" bbl, 1207 from a 6" bbl, 1308 from a 16" bbl, and 1194 from a 4 5/8 in Ruger Vaquero revolver. Based on gelatin data I have seen for the XTP which suggests that expansion may be dubious below about 1150 ft/s, I only use it in the 16 inch carbine, the 6 inch longslide, and the 4 5/8 inch Ruger Vaquero. In the 3.5 and 4.0 inch barrels, I have only used and carried the load with Speer Gold Dots which seem well suited to 1100 ft/s and slower velocities.

As always, the chronograph velocities jump around a bit when spot tested, but remain pretty consistent with my original 5 or 6 shot groups. I haven't kept good data, but it appears the velocities generally remain within about +/-20 ft/s with an occasional shot variation of about +/-40 ft/s.

The performance of the 180 gr XTP from a carbine into gelatin is very interesting. Do you have any data on how a 200 gr XTP would perform from a carbine?

I bought one of these Wiley Clapp GP100 10 mm several months ago from Bud's gun shop. I have been using it as a concealed carry backup in either a Tuff products holster in my back pocket or a Bianchi leather high-ride holster. I carry a 1911 as my primary carry gun with the same ammo. I shot it with some 180 gr XTPs over AA #9 powder that chronograph about 1242 ft/s from my Colt DE. I found the double action trigger to be very smooth. I though the recoil was like a nice push. Some stiff 125 gr 357's that I shot the same day from a 2.5 in bbl 686 produced a much sharper recoil. While it is a little heavy, it carries well and I hardly notice it. A friend has solicited to buy it if I ever want to sell it. Maybe my heirs will sell it to him some day.