Steve, you have a nickel 4" m25-5 in 45 Colt. The grips are Smith & Wesson, but may not be original to your revolver, most 25-5's came with target stocks. The 25-5 dates back to the late 70's and 80's. The 45 Colt is not obsolete and is quiet popular with new loads being introduced often. You have a fine shooter! Bob!