How about cold temperature?
I was out testing in the cold, and the temps did not get above 28 or so. I noticed a larger ES and SD, about 11.6 with a charge of 3.7 gr of Bullseye. It was also pretty windy today, and at times the chronograph was shaking in the breeze, so I guess that would effect the results? Would the cold result in less reliable ignition, compared to when it's 10-20 degrees warmer? Also my hands were very cold, so my hold on the gun was probably not as consistent.
On the plus side they all fired properly, now that the primer seating depth on the 1050 is set correctly (way too high from the factory!) The 952 started to have trouble going fully into battery after another 100 rounds, but I didn't clean from the last time, and didn't relube, so the gun was very cold, dirty, and not wet with lube. For comparison, the M&P9c worked just fine. Not as accurate, but definitely more reliable. I think they both need a good bath...