Home Forums Reloading Handgun Reloading Small Rifle Primers substituted for Small Pistol? .38 special

I used some small rifle primers (CCI 400) for 9mm & a 38 +P load in 357 brass. About 30% of the 38 cartridges didn't fire the first try but they did fire the second try. I contacted CCI and the response I got stated the 400 and 550 primers are NOT the same.