As I posted in an earlier thread, I have been disappointed in my usual 9mm load in my Kimber 1911. This load (5.5 gn of locally repackaged Winchester Action Pistol powder under a 124 gn PRN projectile) is the same as the commercial loading the repackager is selling and which I have used often.
After my last outing with this load I decided to try my old “standby powder” for several different calibres, Tightgroup.
I loaded up some 4.2 gn Tightgroup loads and while accuracy was much better I thought the load felt a bit light so the other day I loaded up just under 150 9mm rounds using a max charge of 4.4 gn powder.
Today I had a bit of time to compare the two loads using a standard drill consisting of:
5 X draw and fire a single shot no time.
Draw and fire 5 shots, no time.
5 X draw and fire a single shot in under 3’seconds.
5 X draw and fire 2nshots in under 3.5 seconds.
The intention of this drill is to fire all A zone hits on an IPSC target at 7.5 and then at 15 meters (with 3.5 and 4 seconds for the timed fire strings) in order to build accuracy. If you don’t get all A zone hits then shoot that string again until you do.
I have shot this drill so often I now start at 10 meters. In order to compare the two loads I decided that what was shot would stand unless the string was so bad. The goal was, the same in competition, 75-80% A hits. I also timed the draw and fire 5 X string in order to get a hit factor to compare.
The results:
First up the 4.2 gn load. The 5 X 2 shot string results were not as good as they should be. of the 10 rounds there were 5 A’s, 4 C’s and 1 “I don’t know where it went”. Obviously a fault on my part so I decided to reshoot that string.
Final result was a score of 110/125 with 80% A zone hits and a 5 shot string hit factor of 2.9639. Most of the timed shots were 2.8 and 3.3 seconds.
Next was the 4.4 gn load. Overall I felt that the load shot much better for me. There were no reshoot strings. Timed strings were under 2.5 seconds and around 2.8-3 seconds for the double shots. The overall score was 117/125 with 88% of shots landing in the A zone. The 5 shot string hit factor was 3.5360. Also apparant was that while the lighter load group was centered to the right in the A zone the 4.4’gn group was centered right in the centre.
I had patched out both targets before thinking to get them boots, so I fired another 10’rounds on the 4.4 gn target the make 35 round groups and took the pics.
Now I know this is not definitive. Had I gotten used to the pistol for the second target after shooting .45 for the last two months? Did my shooting improve as the comparison progressed? And does a .2 gn charge increase, often within the margin of drop to drop of some powder measures, really make such a difference?
I’m not sure either way, but I know which load I’d be more confident shooting out to 35’meters and on Sunday I’ll chrono both loads then shoot the 4.4 gn load in a 48 round Classic Pistol Service Match and compare the score my last one using the Kimber and the 4.2 gn load.
But I think I already know what I’ll be shooting the next time I compete with the Kimber.