Thanks to movies and video games, tons of people join the military thinking they'll be the next John Wick. Gun-hungry recruits salivate at the prospect of sending rounds downrange using all the latest and greatest weaponry. Unfortunately, that rug will be pulled out from under newcomers when they realize that "military-grade" really just means "broken all the time with no money to fix it."
The famous M203 Grenade Launcher is no exception. Yes, it's a useful tool in combat since it can fire a 40mm grenade and reap an entire cluster of souls and limbs. But, in reality, they're big pieces of sh*t.
It's mostly just annoying to have a fore grip.
(U.S. Marine Corps photo by Lance Cpl. Alexis C. Schneider)
You can't really use a grip
There are fore grips made specifically for the M203, but they aren't all that great. The real tragedy here is that you can't add a cool, angled fore grip or any variation. If you choose to use the M203-specific grip, you have to place it somewhere that won't interfere with the reloading process.
When you get issued an M203, your rifle's sling swivel will turn into your personal noisemaker because it's going to click against the M203 with every step you take.
Aiming is a minor inconvenience with an M203.
(U.S. Marine Corps photo by Lance Cpl. Tojyea G. Matally)
It adds weight to your rifle
Granted, the M203 doesn't weigh so much on its own, but as every infantryman will tell you, "ounces equal pounds, pounds equal pain."
Additionally, when you want to fire from a standing position, you'll have to lift the front end of your rifle, which has now been weighted down. This may seem like a nitpick, but after days of little food, water, and sleep, you'll be feeling it. If you get issued an M203, start hitting the gym because you'll need the extra muscle.
If you've got that M16/M203 combo going on, have fun fitting into tight spaces. It's baffling how often that M203 gets in the way. Want to sit comfortably in any military vehicle? Good luck.
Consider yourself lucky if you can reload with it still attached.
(U.S. Marine Corps photo by Lance Cpl. Isabelo Tabanguil)
They fall off
Easily the worst part of having an M203 is that they're not usable 100% of the time. Most will just fall of the rifle after firing a single shot, which is both dangerous and annoying. If you're in a situation where you have to use that bad boy, you don't have time to pick it up and put it back on. This means you'll just have to hand-fire it, which isn't a bad thing by itself, but it also means you don't have the sights of the rifle for aiming,
With these issues in mind, you'll likely not get to fire it often enough for it to be worthwhile. You'll most likely end up hating the thing and it'll feel like dead weight.