I had a 220 in 38 Super and 9x19. Too big and heavy for an 8/9 shot. Holding on any of the large frame Glocks is like shaking hands with a 2x4 for me, and I have long fingers.
Unless you are against a 1911, consider one of those.
Rangers, Glock 21? I will believe it when I see it. Who told you that? If it was a recruiter, then my point is made.
If your goal is to be a better shooter in the Military, get a Beretta 92 and a full size AR-15. Put a lot of ammo downrange and get some good instruction on how to do it right. Perfect practice makes perfect.