The FG42 (Fallschirmjagergewehr, in the German tradition of making four little words into one big word) was a rifle ahead of its time, made in small numbers for German parachute troops during WWII. As a service, the Fallschirmjager had some autonomy in weapons procurement, and they instituted a development program for a weapon independent of the rest of the German military. Going into the war, they used a mixture of MP40 and MP38 submachine guns, K98k rifles, and MG34 machine guns. These weapons were dropped in canisters rather than with each individual soldier, which led to serious problems in actions like the attack on Crete. It was decided that the paratroops needed a compact weapon that could serve as both individual shoulder rifle and light support machine gun, giving the rate of fire of the MP40, the range and accuracy of the K98k, and the suppressing capability of the MG34 (much like the US intention for the M14 rifle).
The result was a very optimistic list of requirements for proposals from armsmakers. Among others, the new design was required to use detachable box magazines, be no longer, bulkier, or heavier than a standard K98k, have an integral bipod and bayonet, fire from a closed bolt in semiauto (for accuracy) but from an open bolt in full auto (to improve cooling and prevent cookoffs), and use the standard 8x57mm cartridge. No mean feat to cram all that into one design!
Impressively, Rheinmetall pulled it off – their design was accepted for production as the FG-42. This would be the first model of the rifle, most easily identified by its very steeply canted grip and stamped metal buttstock. It used a long stroke gas piston, and only a couple thousand were produced before some problems became clear, and the design was modified. The bipods were too fragile, the bipod tended to rattle out during firing, the stock was prone to damage, the grip was uncomfortable to use, and the gun was too light to be controllable in full auto fire (remember how I mentioned the M14?). Still, the original design was quite the achievement. The side-mounted magazine was used so that the trigger mechanism could be mounted farther forward than is possible with a bottom-feed magazine, and thus the receiver could be kept shorter. To the same end, the recoil spring was extended into the stock. The guns all had integral rails on the receivers to allow mounting of small optical sights, and the iron sights could be folded down for a clear field of view. You might still see some of these features on more modern rifles…
When some of the faults because apparent, redesigns commenced, and the result was the second model of the FG42 (these changes were not reflected in contemporary nomenclature, and there were many small incremental changes – in hindsight, we separate the guns into two basic types). The later guns were bulkier and heavier, which aided automatic fire somewhat. They used a wooden buttstock, and had improved bayonet retention. The grip was changed to a much more orthodox vertical design, and the bipod was moved from the midpoint of the barrel out to the muzzle. An adjustable gas regulator was also added to the second model guns.
A few thousand more of the second model FG42s were made before their expense and complexity drove them out of production in favor of cheaper designs like the StG44.
We are fortunate to have had access to a second model FG42, and you can see several dozen detailed photos of it disassembled inside, on the FG42 page of the Vault. The rifle was deactivated by removal of the magazine well, but all its internals are intact, and even a destroyed FG42 is a rare bird.
As always, much higher resolution copies of all the photos are available for free download to anyone willing to sign up for email updates.