I thought the 40 was going to be the perfect round because it was between the 9mm and 45 acp. I got my P99 with S&W 40 and thought the gun was not very accurate. Then I got a compact XD in 40 and same thing. I was given a new compact XD 9 mm for doing some work and I was able to shoot much better with it. The 40 is just to snappy for me. I think it's easier to shoot the 45 acp than the S&W 40. I pick brass up all the time at my range and have to say the 40 is the most popular. 80% of the brass I find is 40. It was just not meant to be for me.