"En bloc", of course, is French, meaning "in a single block". It derives from the CLIPS for the various Berthier rifles, all of which utilise MANNLICHER magazines.
The Americans had very much a slavish devotion to everything French at the time of the Great War, being that France had helped the US during its own Revolution and, when the French were revolting themselves, the Americans stood back and watched with wonder. Somehow, the Yanks managed to ignore the less savoury aspects of things (the Terror, 25 years of war under that interesting little Corsican, several more revolutions and revolts and Restorations and Empires). By the time War One came along, the French were on their Third Republic, having cast aside 3 Monarchies, 1 Directorate, 1 Consulate, 2 Empires, various and sundry Revolutions and even a couple of occupying foreign Armies, one after each of the Napoleons. All of this blinded the Americans and they thought evidently that whatever was French MUST be the best.
So they entered World War One and tried to use the Hotchkiss MG even though they already had the far-superior Vickers, tried to use the CSRG even though this meant spurning the superior Lewis, tried to use the 75 even though they didn't have the correct specs to make it. Factories tooled to make the Nieuport fighter after it was obsolete, ignoring the Camel and the tough-as-nails SE5 and so forth and so on. Finally the Americans started using American designs and, once they got them stopped from falling apart, things stabilised and Production got underway. Even the Lewis was allowed to come home again and seems to have remained; it is the guts of the M-60.
But this idea of the en-bloc CLIP stayed on. Garand (but what did he know, anyway?) wanted to use Lee-type MAGAZINES on his rifle, but was constrained into working with CLIPS because Pederson wanted to use CLIPS and Saint JMB had said that Pederson was the world's best designer and NOBODY (to this day) has dared say that JMB did not walk on water...... so the PEDERSON CLIP, an en-bloc type, was used in the GARAND rifle which worked very well and in the PEDERSON rifle which failed the tests. So the US adopted the GARAND rifle with PEDERSON clips. There followed immediately a motion to fire that Canadian fellow Garand, now that they had his design (and so very cheaply; poor Garand was being paid a third of what Pederson was getting.... and Garand's design won!): a salary unit which could be saved. More HONOURABLE heads on the Board (heads with such names as Whelan and Hatcher and many others) turned this down vociferously.
The US entered the semiautomatic combat rifle business with a vengeance and today, almost 80 years later, guys with SMGs are crouching in jungles and under rocks, waiting for that "CLANNNNNNG!!!!!" which announces that The Other Guy has shot his rifle dry.
But we can blame it all on the French.
That's okay; they'll find something to blame on us.
That's what being friends is all about!
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