Break That Case: A Visceral Illustration of Primary Extraction, with Bloke on the Range

Back in the days of the fighting bolt action rifle, clever small arms designers came up with a number of minor but ingenious features to make the soldier’s life a little less hard when trying to cycle their rifle’s action by hand as they faced down the enemy. Many of these special features have since made their way into many of the world’s modern hunting rifles, but they were pioneered by designers coming up with new and better weapons of war.

One of these detail features that got a decent amount of press and attention once upon a time is called primary extraction. The idea here was that a rifle would have some kind of special camming surface in the receiver which would act against surfaces on the bolt to provide a mechanical advantage in the initial part of extraction. If the rifle had a stiff case, this extra leverage would help the soldier get the case unstuck from the chamber so that he could continue fighting.

To better illustrate how this works, TFB’s own Mike B on his channel Bloke on the Range set up a few rifles with deliberately bunged-up cases to show his viewers how a little extra leverage goes a long way:





Nathaniel F

Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. In addition to contributing to The Firearm Blog, he runs 196,800 Revolutions Per Minute, a blog devoted to modern small arms design and theory. He is also the author of the original web serial Heartblood, which is being updated and edited regularly. He can be reached via email at nathaniel.f@staff.thefirearmblog.com.


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  • Major Tom

    That extra leverage is why like on a Mosin-Magant it’ll eject an unfired cartridge all the way across a room.

    • Sledgecrowbar

      I think you might just be using the hammer too hard.

      • Major Tom

        What hammer? I barely pulled the bolt back and it just shot across the room some 5-6 meters.

  • Joe Moore

    Yeah I like him and the video, but the M1 definitely has visible primary extraction.

    • gunsandrockets

      Yeah, the Mini-14 has the same thing.

    • In later comments, he corrected himself on the M1. In his defense, it is very small and hard to see.

  • Dougscamo

    My father served from ’40-’45 in the US Army….started with a Springfield and transitioned to the Garand before going to the Pacific….enjoyed telling about having to kick the bolt open to eject the case numerous times on his Garand….
    Darn good video and amazing that it is still available!