Our club sets up two tables at 15 yards away, 5 pins each except we cut the top 6" off the pin and set up 3 tops with two bodies on the ends. So using a large caliber magnum isn't necessary. Shooting just the tops at 15 yards is plenty challenging and fun since we shoot head to head.
I use either my 4" model 10 38 special or my 4" 686-6 depending on what mood i'm in. For the most part I use my reloads. 148 grain wadcutters over 2.7 grains Titegroup set at COAL 1.18". Even at 15 yards those loads will penetrate a pin & protrude maybe 1-2mm out of the body. Another favorite load I like is 158 grain LRN over 4.8 grains Power Pistol COAL of 1.455" and finally a 158 grain SWC-HP over 3.8 grains Titegroup & COAL 1.590". These loads mentioned are a great balance between knock down power & accuracy.
The last several pin matches that I shot at a local indoor range were the man on man variety. I shot my Glock M-35, .40 S&W with a Lonewolf ported Barrel. Ammo was some of my handloads with 180 Hornady XTP's at about 900 FPS. Worked nicely with little muzzle flip.
Here is a dead on shot of one of my wadcutters in a pin head. Our club sets up 3 pin heads and two pin bodies at 15-17 yards. This was with my model 10-8 4" heavy barrel 38 special using fixed sights. The recipe for my wadcutters is Hornady 148gr HBWC, 2.7gr Titegroup & OAL of 1.18".