124 grain coated round nose and Prima V was the winner today. But all the targets I have fired look pretty much the same when fired off of a rest. What I have tried so far:
124 MGHP, 4.3 grns of N320 loaded to 1.110
124 ACME, 3.9 grns of Prima V loaded to 1.125
124 MGRN, 4.1 grns of N320 loaded to 1.140
135 ACME, 3.5 grns of Prima V loaded to 1.135
147 ACME, 3.4 grns of N320 loaded to 1.110
147 ACME, 3.0 grns of e3 loaded to 1.110
About the only real difference in any of the groups I found was that the 124 grain bullets printed slightly lower than the heavier ones, otherwise the groups sizes are a coin toss and range from 1.125 to 1.5" for 5 rounds.