Ive been using a 358156 in .38 brass crimped in the 1st groove over 12.2 gr of 2400 with standard primers. They fit in my Ruger Speed Six .38 Special and the accuracy is excellent; as a matter of fact this load shoots awesome out of all my 357's too. No unburnt powder. Basically my go to mass production load now. Don't have a chrony; but I don't care how fast their going with that level of consistency! Absolutely no signs of pressure brass just falls out.