My Father is 73. He is retired from the Air Force and has firearm training. Has decided he wants a home defense pistol. I let him try out my 6" barrel .357. He liked it but wanted something slightly smaller in 4" barrel. He wants a revolver. Worried about recoil in smaller frame but also want it to be capable. Could go with .357 and use .38 if too much. Saw a .45 revolver which was interesting. Any ideas?