I have several different "Trail Guns", but I hold two in high regard:
631 S&W .32 H&R Magnum with a home cast 100 gr Keith or a wadcutter bullet ahead of a load of Bullseye or Win 231:
My other favorite is the S&W Model 60-4 in .38 Special. My preference is to load home cast H&G #251 dbl ended wadcutters:
Of course, if it is just a day plinking, then it is hard to beat the ol' .22/.32 Kit Gun:
I am very partial to center fires for small game use. I have had better results (terminal ballistics) on live game with center fires. Does the job without tearing up meat too badly. I have had some failures with the .22 rimfire out of rifles, much less, a handgun when head shots are not offered.
Dale53