Ok, 44 grs of Varget is your starting point, so now what? The safest method of finding your maximum load is by shooting across a chronograph. One of three things will happen; your accuracy will drop off and you'll loose interest in proceeding further, you will reach 2900 fps where you should stop as this is the maximum velocity listed for Varget with a 150 gr bullet in several manuals (assuming you have a normal length barrel), or your velocity increase will plateau. This indicates that the maximum pressure is near, in which case you should consider half a grain below this load is maximum in your rifle.