Quantcast
  1. Sign up now and join over 35,000 northwest gun owners. It's quick, easy, and 100% free!

Minimum impact to discharge bullet primer???

Discussion in 'General Firearm Discussion' started by Rotty, Jan 29, 2013.

  1. Rotty

    Rotty Skagit County Active Member

    Messages:
    513
    Likes Received:
    221
    I only ask this question because....I don't know. What would be the minimum impact to set off a bullet? If the trigger pull on single action is 5-6 lbs how much force is actually being applied to the primer when the hammer strikes the firing pin and the firing pin strikes the primer? Max impact most likely varies from each gun/rifle/shotgun. Knowing the max impact is not as important because the end result is.....BANG!!! But I would like to know what the minimum amount of impact is needed to set off a bullet.


    More curiosity than anything.:)
     
  2. raindog

    raindog Portland, OR Active Member

    Messages:
    574
    Likes Received:
    145
    Geoff on Dropping the M1911

    "Reading through Hatcher’s Notebooks, one finds that he established primer detonation force is in the range of 12 in./oz. for “no fire” to the upper scale of 60 in./oz. for “all fire.” This was for 30 cal. centerfire rifle ammo."
     
  3. moose

    moose northwet coast Well-Known Member

    Messages:
    1,160
    Likes Received:
    354
    It depends on the primer. Some primers are harder than others. Federals are on the soft end of the spectrum, CCI's on the harder end. Military primers are even harder, mainly to prevent slamfires.
     
  4. Rotty

    Rotty Skagit County Active Member

    Messages:
    513
    Likes Received:
    221
    So if you manually de-cocked a 1911 style hand gun used in that article with a round in the chamber. You could reasonably do so without discharging the weapon. As per the article;

    Quote
    Reading through Hatcher’s Notebooks, one finds that he established primer detonation force is in the range of 12 in./oz. for “no fire” to the upper scale of 60 in./oz. for “all fire.” This was for 30 cal. centerfire rifle ammo. We’ll assume, for the sake of argument that there’s no substantial difference between primers of various brands and sizes. The midpoint between the “all fire” and the “no fire” is 36 in./oz. I’ve just weighed a half dozen firing pins from my parts box and come up with an average of 65 grains, or .148 oz. If we have a free floating firing pin with no spring to impede forward movement, dropping the gun perpendicular on the muzzle from a height of 10 feet will generate almost 18 in./oz.
    Again, assuming Hatcher’s midpoint of 38 in./oz. would cause 50% of the rounds to fire we’d have to drop the gun, muzzle down, from a minimum of 20 feet. We’re approaching Dean’s figure of four stories here. Once we add the FP spring to the equation – and my (VERY) informal testing of spring weight indicates a rate of between 3 and 3.5 Lb. So we add 48 oz more to the 36 to overcome the spring and then set off 50% and we’re getting into a drop range that’s achieved only be mountain climbers and pilots. The same values hold true of falling on the hammer (if down). Unquote

    The in./oz ratio I don't quite understand but the explanation comparison of dropping the gun 20 feet to reach 50% potential of discharge was more my speed.
     
  5. Mark W.

    Mark W. Silverton, OR Bronze Supporter Bronze Supporter

    Messages:
    5,782
    Likes Received:
    4,988
    in/oz is a torque measurement like foot/pounds only less