The evolution of western 40mm grenade launchers is a bit of a back-and-forth affair. Initially, we had the M79, which is a single barrel, break-action weapon with its own wooden stock. Sort of an old shotgun given a huge dose of steroids. It was proven super effective in Vietnam, launching a very reasonable amount of high explosives with a minimum of setup. Of course there were drawbacks, especially due to the low rate of fire and limited amount of rounds that could be carried.

The first approach to fix this was called the “China Lake Grenade Launcher.” Taking yet more cues from shotguns, this was a pump-action grenade launcher, with a three-shot magazine for the fat 40mm rounds. Where the M79 weighed about 6 lbs empty and 6.5 lbs loaded, the China Lake launcher weighed 8.2 lbs empty and about 10.2 lbs loaded. Usage was mostly confined to Navy SEALs, who were generally fond of the weapon. The US Army was focused on its SPIW program, which would end up going nowhere. Unfortunately, that meant that the sensible China Lake launcher also went nowhere.

The other approach was the cheap and cheerful M203, an underbarrel launcher that attached to the rifleman’s M16. It’s much lighter at 3 lbs, but has a shorter effective range and makes the rifle a bit awkward to use. Also, the sights aren’t integral with the M203, which leads to more opportunities to lose or screw up a zero. Some standalone launchers were made starting in the 90s, but they never achieved much in the way of widespread use. The original M203 attaches to an M16A1 or M4 by means of a pair of barrel brackets. Some newer variations can be attached to picatinny rails instead.

Replacements to the M203 have been concerned with fixing some of its less than desirable traits, chief among them the inability to use longer ammunition. The US Army’s replacement for the M203, the HK M320¹ does this by means of a side-opening action. It also has an integrated grip to facilitate standalone usage, and has integral sights. These don’t have to be rezeroed if the launcher is moved between rifles or attached to the stock kit. However, the M320 is a bit heavier than the M203. The integrated pistol grip and included vertical folding foregrip seem to indicate that the M320 is optimized for standalone use.

The big competitor to the M320 is FN’s EGLM, which had an extension to move the trigger down where it could be fired from the rifle’s regular grip using the middle finger of the rifleman. Extensions are available for both 5.56 magazines and 7.62 NATO magazines. The EGLM can also accommodate longer rounds, but does not have integral sights. Also, like the M320, it has a double action trigger. This is marketed as giving second strike capability, but I really don’t think that’s all that important given that you aren’t using super old grenades.

So let’s get to picking. There are a bunch of other grenade launchers out there that are marketed in packages to go with various other service rifles, but that’s not a big deal to us M4 users in Borgundy. And when I go looking for fancy rounds that you can’t fit in an M203, I mostly get a bunch of “less-than-lethal” options². Great if you’re the LAPD, but I don’t really see the utility for standard issue to the infantry. The other thing that you can load in the EGLM and the M320 is the Pike missile, which is a pretty cool laser guided mini missile with about 2,000 m of range. However, that’s quite a bit of reach for the regular grenadier in the rifle squad, given that the standard 40mm round has an effective range of about 400 m. Again, it seems kind of a niche weapon. Great for special forces. I’ve also mentioned that I’m not buying the second strike argument as anything anywhere close to necessary. The M79 and M203 don’t have that, and soldiers have been using those effectively in combat since the 1960s. And at the end of the day, the venerable M203, even with the picatinny rail adapter, is going to be way cheaper than the competition.

So we’ll go with the M203A2 (or equivalent; the M203 is a widely licensed system), which has the picatinny rail attachments. We’d want to purchase the stock kits to go with these as well, since we’d expect³ these to be used more often in the standalone configuration as long as we can keep that configuration reasonably compact and light.

We should also talk about the the Milkor MGL (M32 in US Service), which is sort of like a successor to the China Lake Launcher idea, albeit from South Africa. It has a six-round, revolver-style magazine. Clearly, it’s trading weight for capacity. An M203 in standalone configuration weighs a bit less than 5 lbs unloaded, depending on options.⁴ The six-shot M32 weighs 15.4 lbs unloaded. And that revolver magazine makes for a pretty bulky gun. Anyway, I’m kind of skeptical of the M32, given that the grenadier is still likely to have to carry a carbine in addition to it. At least the rounds it fires actually work, unlike the XM25. I think it would be reasonable to procure some M32s, but I’m not really sure where to put them in the TO&E. Probably in the back of a vehicle somewhere.

And there you have it. Cheap and cheerful launchers for cheap and cheerful grenades. In terms of basis of issue, I think two per squad is a pretty reasonable choice.