I recently posted a range report on another forum about shooting 3 different 9mm handguns with reloaded ammunition. In that post, I noted that my reloads were too long for the S&W M&P9 2.0 compact. The first round I tried fired, but the second failed to go fully into battery and jammed the gun. These very same loads functioned fine in my HK VP9, Sig P365, Ruger SR1911 Cmd and Ruger SR9C. I was using Winchester brass and Sierra 125 gr JHP's. The data that I used was from LoadData.com. It listed 1.130" as the COAL of their loads tested with that bullet. I later downloaded Sierra's Volume 6 reloading data app to my iPhone. Their data shows an overall length of 1.030", or .1" shorter than LoadData.com's data. At first I thought I might have misread LoadData's info. I did some digging and found a printout I made and sure enough it said 1.130".

Tonight I read an article in the January 2021 issue of Shooting Times. The article was entitled "Fast 9mm Loads." I was surprised to find that they too discovered the the M&P's have a short-throated chamber. As a result, they had problems with their handload's COAL functioning in their M&P. They ended up shooting them in a Glock 19.

I have loaded thousands of rounds of ammo for semi-auto pistols over the years. The majority of these were .45 Auto, but many were .40 S&W and some were .380 Auto and .38 Super. I have had more difficulty reloading the 9mm rounds, than all the others combined. I find that they are pickier about case length, and now I find that there are some differences in chamber throats too. They say that there are more 9mm handguns in the world than any other. You would think they would be more uniform.

As a side note, shortening overall length as much as .1" can cause a rise in chamber pressure. I need to revisit my powder charges to make sure they are safe. I refuse to maintain different COAL's for different guns. I will drop all my 9mm handloads with 125 gr Sierra's overall length to 1.030" They should still function in my VP9, P365, SR1911 and SR9C. Have any of you have noticed this problem in your M&P's?