Good evening, guys! Here is the first operational LMG, the danish Madsen. Based in the falling block mecanism (an odd choice, at least for an automatic weapon), it was a reliable weapon, built in an astonishing variety of calibers, both rimmed or rimless, stock appearence and barrel lengths. As a proof of its quality, it was sold from the russo-japanese war to the post-WWII era, to more than 34 countries, and was used in almost all the continents.
The danish Model 21 was closely related to the previous model 1903. It was chambered for the rimmed 8x58 danish round.
The short barreled Model 15 was considered as "machine carbine" by the Netherlands East Indies Army. It was chambered also for a rimmed round, 6.5 x 53.
The finns selected the Madsen Model 20 in the russian standard round with a long barrel.
Model 29 had a different stock with a double set of triggers, it was capable of being fired from a tripod and from an AA mount.
Finally, Model 47 chambered in 7.92x57 was employed by Portugal well until the 1960s in Africa.
Credits: I copied Scootia's shading for the rivets and round surfaces (and plagiarism is a sincere form of praise