MARSOC is fairly obvious, with Recon Rickies a close 2nd. But there are times when it may be beneficial in S-2 roles or Civil Affairs. Shit, I was a gun bunny but still mexican'd a M9 when my Lt wanted me to come with him to meet the locals. We had fully geared up Marines around but I guess since I was 6'5" and looked like a serial killer at the time I was a good fit to "down dress" with him.
Keep in mind that this is not the first time that the Glock 19 has been issued. It's just that they have gone from the Gen3 to the Gock 19M. MARSOC and I believe Force Recon have been deploying the Glock 19 Gen3 for a while. Other branches have also been using the Glock 19 for a while with their special operations folks.
I think the main reason for the Military Glock 19 vs the Glock 17 are similar reasons that the Civilian CCW community greatly prefers the 19 to the 17. I's small enough to easily conceal yet large enough to shoot effectively. I've been told by our Glock rep that the US Civilian market buys 9 of the model 19 for every 1 of the 17 sold.
After studying the thread, I think that since the Sig offering has been derailed, Marines are hoping that Glocks will replace it. Hence this public attempt to start buying them. Also, being that the Marine Corps historically has been underfunded, their worn out and lost equipment from Iraqi and Afghanistan wars may include large numbers of handguns. Therefore, Marine Corps pistol reserves may be slim. I have no data to back up my comments about low handgun reserve.
I think that Marine leadership also saw what a waste the MHS was when multiple people in powerful roles where hinting that the Glock the was easiest choice. Not to mention almost two decades of Glocks successfully filling the role. The Marines like to spend money, as shown by the current push for a HK for every rifleman, but after the IFV program I think they have stayed away from dog and pony shows.
The old time saying about the Marines being underfunded and under-equipped is mostly irrelevant since 05-07ish or so. They are fickle about money but the units that have needs are taken care of. Like every service, there are units that have wants but no real needs. I think that is where some of the grief arises.
Well, perhaps the Marines have smarter E2's and O4's than the Army used to have, but as much as I like the G19, unless the pistol was only going to be used by Raiders/Recon and the like--who tend to be a bit older and have a lot more training--I'd really want a safety on that pistol. Because when troops start shooting their legs the blame will end up on the Gunny's and the like and not on the general officers.