CMP rules state once every five years you have to shoot at least 50rds at silhouette targets during an organized Club event. It doesn't require you shoot a M1, follow an officially sanctioned NRA/CMP Service Rifle course-of-fire, or even hit the target. As long as it's a Club "organized event" you could qualified with a Daisy Red Rider at 10 paces, or with a handgun on a 50ft indoor range.
If your not looking for a private shooting range to join (which might cost $65 to $250 per year), my recommendation would be to join your State CMP affiliate (usually less than $20/yr), then look for a local pistol club/range that allows non-members to compete in handgun silhouette matches, most do to encourage new members and charge a few bucks more. The match might cost you $10 - you provide your own ammo and gun. The club you shoot at does not have to be CMP affiliated, but they do have to be able to provide you some kind of score card or letter stating you shot the 50rds.
Bottom line is you can use any kind of cartridge, rifle, handgun, or pelletgun that the club allows. The CMP has no specific requirement in that regard. -- Kernel
