Geth Reviews an Okay Gun: The Type 100 Submachine Gun

 Now, I reviewed two weapons prior that were pretty terrible, the Chauchat and the Type 94 pistol. Both of these weapons had so many flaws I was forced to give them bad reviews. The Type 100 SMG of Japanese WW2 fame was far from the best gun deployed, but on the whole, it was quite good for what it was made for and the limitations its sponsor nation had.

First, a little background. Japan was oddly late to the idea of incorporating SMGs into their arsenal during World War II. Despite having battlefields ideal for their deployment and being well suited for the mission they needed them for, they showed oddly little interest until very late into the war, and they never deployed the gun in question in very large numbers even after they proved their worth, likely due to shortage of materials over any other reason.

Like many Japanese weapons of the period, it is a product of Kirijo Nambu, who made and/or refined practically every weapon the Japanese would carry as small arms. While some of his designs were pretty horrible, like the Type 94, this was actually a pretty decent weapon design. After a few false starts with some earlier prototypes that never saw much use beyond proof of concept prototypes, the Type 100 (formal name 一〇〇式機関短銃, Hyaku-shiki kikan-tanjū) was finally accepted for deployment in 1940.


Before covering the gun features, it bears noting this was a very late time to consider submachine guns compared to every other force in WW2. It would have been far more useful to their arsenal several years prior, as SMGs were ideal for use in the jungle and for close-quarters assault missions as opposed to rather ungainly long rifles and machine guns.

That aside, it had at least three variants, the 1940 original, the paratrooper version of the 1940 model, and the 1944 late model.

Here is the list of features common to the original model:

• The ammo used was the standard, slightly underpowered 8mm Nambu pistol cartridge. While not as powerful as the rounds used by other nations, it was more than adequate for the limited mission needs of the Japanese.
• The design takes a LOT of cues from the German MP18 of World War I fame. Given it was the basis of many designs of the period, including the Beretta SMG the Italians used, this was not a bad choice for the base concept. The gun was a mix of wood and metal, with wood making up most of the furniture of the weapon.
• The feed mechanism was a good idea in theory but not so great in practice. It was designed so a round had to be fully chambered before it would fire. While an ideal safety feature, this meant you couldn't even do a dry fire to check the cycle of action, you had to have some sort of round fully loaded. This also hurt the fire rate, it being a rather paltry 400-450 RPM (Rounds per minute) at best on a good day.
• It was plated with chrome for easier cleaning around the barrel. The barrel also had an integral compensator.
• It had adjustable iron sights.
• It had a curved box magazine with a 30-round capacity.
• The firing mechanism was a blowback action. While adequate, the complex safety features hobbled the firing rate.
• It had support for a bipod, muzzle brake, and bayonet lug,

The paratrooper variant was more or less similar to the original, except the stock was made for folding via a metallic hinge. While a practical idea, given the need for portability, it did slightly weaken the integrity of the gun due to the fact it effectively loosed the front and back ends of the stock, making for slightly worse recoil.

The late 1944 variant, which was most often encountered later in the war, was greatly simplified and was much cruder than the earlier versions, losing many frills and niceties in an attempt to streamline production.

To cut costs, a lot of features were cut down, removed, or simplified:

• The adjustable tangent iron sight was replaced with a fixed welded peep sight. This was arguably the biggest downgrade since this meant the sight could not be adjusted and if it was welded crooked, you were basically stuck with a bad sight that was already marginal at best.
• The finish and quality took a nosedive. The wood and metal were not finished, lots of welding was used wherever possible, and this was not very fun to hold with ungloved hands.
• The muzzle brake attachment was deleted and a much simpler integrated version was done by drilling a port hole or two into the barrel end.
• The bayonet lug was replaced with a much simpler attachment point. The bipod attachment was deleted.
• The stock was reverted to the non-paratrooper version, which was actually a good idea, the paratrooper version was less sturdy.
• The complicated fire control mechanism was removed and the rate of fire increased to 800 RPM

Essentially, this late war version wasn't that much of a downgrade in overall performance aside from the sights and it did see some use in many of the latter campaigns. It's only real flaw aside from the inherently low powered ammunition is the limited number produced, as Japan did not have the ability to make these in numbers that would have made any real difference.

That said, it was overall a weapon that "too little, too late", but that could be said of a lot of their war efforts, so this gun alone was not going to make or break the Japanese forces any worse than they were historically. Regardless, it was one of Kirijo Nambu's more competent designs despite it's flaws, and while I'd prefer something better, it was, at worst, acceptable for the mission assigned to it, just never produced in quantity that mattered.