I decided to give this another try last night just to see if I came up with the same results. 40grains fffg goex loaded no problems.
My powder measure is not marked with the number of grains you are loading, the lowest setting is 20 grains and you have to count clicks in five grain increments. I must have clicked one time too many the first time I tried this and was probably loading 45 grains instead of 40. It's not one of those twist and click measures, you have to pull one tube out from the main tube to adjust it and it takes a bit of pressure to do it. Sometimes I'm too cheap for my own good.
If I was loading 45 grains before, at least I know that the gun will shoot that much with no problems and I'm glad that BP allows you some tolerance for errors. That's exactly why I don't reload anything smokeless, I'm my own worst enemy sometimes...
