My load for my Swiss K-31 using 150 grain pellets (Hornady SP Interlocks or SSTs) uses 45 grains of IMR 4064 with CCI 200 primers. Since the K-31s have very short throated chambers, I set them for an OAL 2.875". I mounted a no drill and tap scout scope mount on this K-31 and with a 2X7 inexpensive scope, I'm getting 1/2" three shot groups at 100 yds.