I set up the chrony for some 9mm loads today. I had previously loaded some light win 231 loads and had a few issues. The bullet I used is a Rainier 'plated' 115 grn RN. I set the COL at 1.10 & 1.09. The gun was a 92fs. The 1st loads were with a 4.1 grn charge of win 231. I would get a stove-pipe on average every 3-4 shots. I used that charge from the lower spectrum of data from my Sierra manual. I later see the Hodgdon site has 4.3 - 4.8grn win 231 for a 115 lead bullet. I think I would be fine if I bumped up the 231 charge some. Four shots through the chrony averaged 959fps. The data with the 4.3-4.8 lists expected fps 1079 - 1135. Win 231 also gets high marks as a 9mm powder overall. These cases also ejected right next to the gun, one foot over. My next load was 4.2 of Tightgroup with the same bullet. The Hodgdon site lists a range of 3.9 to 4.3 with a 115 grn lead bullet. This load cycled great, the cases were ejected about 4 ft from the gun. I averaged 1087fps, all within about 40 fps of each other. The 'book' speed for the powder range was 1075 to 1151, so it's right where it should be. The thing about Tightgroup is you have to be very careful with those small powder charges. I weighed each charge and double checked a few times & zeroed the electronic scale often. I have some older reloads with Bullseye powder to burn up but after that I may just stick with tightgroup. Anyway, just though I would pass it on.