Privacy guaranteed - Your email is not shared with anyone.

Welcome to Glock Forum at

Why should YOU join our forums?

  • Reason #1
  • Reason #2
  • Reason #3

Site Description

Super slow motion camera and recoil

Discussion in 'General Firearms Forum' started by ithaca_deerslayer, Mar 27, 2012.

  1. I found this super slow motion youtube video of recoil.

    [ame=""]Firearm cycling slow motion / ciclo das armas camera lenta - YouTube[/ame]

    Does the barrel start to rise before the bullet leaves?

    I've heard it said that slower loads shoot higher from a handgun because they are in the barrel longer. Do you think that is actually true (or if true, is it true for that reason?).

    How much does follow through affect accuracy?

    These are the sorts of questions of interest to me when I look at this video :)

    Oh, also, anyone know of video like this with a Gen 4 Glock so we can see exactly what is going on with the brass to the head ejection pattern :rofl: Do you think Glock has such video? The must have, I'd think.

    Good news is my Gen 4 Glock 17 hasn't brassed me in the head as much recently. Problem seems to have virtually fixed itself.

    And finally, what the heck really is a double-tap??? Because I don't see anyway two bullets are coming out for one recoil :)
    Last edited: Mar 27, 2012
  2. Maine


    Sep 19, 2009

  3. Highspeedlane

    Highspeedlane NRA Life Member

    Jan 25, 2008
    New England
    In all my experience, higher velocity loads tend to print lower on the target at a given range and I've always attributed that to the projectile exiting the bore at a lower point in the arc of recoil.

    Conversely a slower projectile leaves the bore at a higher point.

    Follow through is very important as well.
  4. I believe that the bullet has exited the barrel before the muzzle climbs or recoil begins.
    The flash can only leave the end of the barrel after the bullet has gotten out of the way.
  5. I don't know if this is true or not.
    I don't think it could be in a handgun barrel length.
    I suppose it is possible in a long rifle barrel.
    The slowest bullet is going over 800 feet per second.
    How long is it in a 5 inch barrel.
    I think it is gone before any recoil is started.
  6. bac1023


    Sep 26, 2004
  7. cowboy1964


    Sep 4, 2009
    That case coming out of the AR is awesome. Maybe Gen 4's need a brass deflector!
  8. cowboy1964


    Sep 4, 2009
    hickok45 has said repeatedly that slower bullets impact higher. I've never bought into that but I've shot maybe 0.0001% of the rounds that guy has so what do I know.
  9. DJ Niner

    DJ Niner Moderator

    Feb 13, 2001
    North-Central USA
    The movement of the bullet is what causes the movement of the firearm (recoil). They both start moving at the same time, but the weight/mass of the handgun is far greater than that of the bullet, so the bullet moves fast, and the gun moves comparatively slowly.

    If you have access to a magnum revolver, here is an experiment that you can use to prove the gun moves slightly before the bullet leaves the barrel. Put the (unloaded -- double-check, please!) revolver upside-down on a flat surface, balancing on it's front and rear sights. Find a straight rod about twice the length of the barrel, that is small enough to fit inside the barrel. Slide the rod a little more than halfway down the barrel, and make sure it is laying flat on the inside of the barrel. Now look at the part of the rod sticking out of the barrel, and what it looks like in relation to the flat surface the gun is sitting on.

    The flat surface is the line-of-sight; the handgun's sights are both touching the surface, so we know the top of the front and rear sights are aligned with the flat surface. The rod will be slightly angled upward, away from the surface. This is the line of the barrel (or bore).


    If you flip this image over so the surface is on top and the rod is on the bottom, you now know that the bore line of the barrel is actually pointing BELOW the line of the sights, and angled away from it, so the line of sight and line of the bore would never cross paths in front of the gun.


    This means that the barrel is actually pointing BELOW the target when you align the sights on target, and when you fire, the rotational movement of the gun barrel upward allows the gun to "spit out" the bullet as the line of the barrel/bore rotates past the target, and then it continues on upward through the arc of recoil. It only moves a little bit before the bullet leaves, but if it didn't, the bullet would never get to the center of the target.

    This is more noticeable in a revolver, as the entire weapon rotates as a single unit in recoil. In an autoloader, the slide and barrel move first, and they move in a linear fashion, so the entire weapon does not move as far rotationally as a revolver does, all other things being equal. Due to this, sights on autoloaders are not off-set as much as on revolvers.

    The slide/barrel assembly on autoloaders does start to move to the rear prior to the bullet leaving the barrel. Again, they only move a little bit, but they do move. Check this super-slow-motion video of guns shooting:

    [ame=""]Guns in Slow Motion Compilation - YouTube[/ame]

    At 3:47, an autoloading pistol is fired, and you can see the slide/barrel start to move rearward (the tiny graph-paper stickers on the slide and frame show the difference from their original position). Then you see the air that was in the barrel in front of the bullet (along with a small amount of gasses that blew past the bullet) leave the barrel. Then finally at 3:49, you see the bullet leave the barrel.

    Here's one with a revolver. You can clearly see the precursor wave (air and some gases) exit the barrel as the barrel begins to rise, then you see the flash at the barrel/cylinder junction, then you see the bullet leave and the muzzle flash. The end of the clip has the slowest slo-motion of this shot; watch it in full-screen mode, starting at about 14 seconds into the clip, with your focus on the end of the barrel:
    Last edited: Mar 28, 2012
  10. RedHaze

    RedHaze Handgunner

    Aug 23, 2009
    SE WA
    Double tap, otherwise called a hammer pair, is not two bullets for one recoil.

    It is two SHOTS, one sight picture.
    You align your sights and lock onto the front sight, press press.
    In the Marines we used hammer pairs at indoor distances. With a max of about 10 yards. Usually you'll get two holes about 2 inches apart almost vertically.

    Anything farther out than that got a controlled pair. two shots, two sight pictures.
  11. English


    Dec 24, 2005
    An excellent find ithca. The first sequence answers your question (answered in another way by DJ Niner). Here you can see the slide, barrel and muzzle brake start to recoil before the first and second burst of flame from the compensation ports. If that assembly is recoiling the barrel must also be rising. As a small amount of rise will produce a big difference in point of aim, even at 5 yards, that muzzle lift is small relative to the movement of the slide and so it is not easy to see, but it must be there.

    This effect has to be much greater in a revolver because all of the recoil force has been transmitted to the frame by the time the bullet is leaving the barrel. In an auto, much of that force in still contained in the momentum of the slide and barrel as the bullet is leaving the barrel and so the only force acting on the frame which can produce the rotational couple is the small amount of recoil spring compression. The rest of that momentum is transmitted by increased recoil spring force as it is compressed and by the impacts as the barrel and slide are brought to a stop, but that all happens long after the bullet has left.

    The other thing that is different about the auto is the barrel unlocking process. If, as is usually the case, the barrel unlocks by dropping down at the breach end, that too tilts the barrel upwards. If the recoil moves the assembly far enough to start unlocking before the bullet leaves the barrel then that too will elevate the point of impact and a slower, heavier, bullet with more momentum will give more time for this to happen and lift the slower heavier bullet's point of impact relative to a lighter faster one's.

  12. Thanks for that info.

    So, it seems you could do the same thing for a tripple tap. Press, press, press. Or even a 10 tap. (Deca tap?).

    Perhaps as long as you are not readjusting your sights, but rather just bringing them quickly down to the starting place, and quickly pulling the trigger again, it is a tap? Double, tripple, quad, as long as you can keep doing it without having to pause to readjust with extra movements.
    Last edited: Mar 28, 2012
  13. Tombo 65

    Tombo 65

    Jun 3, 2011
    I reload a lot, and I prefer bullets heavier than typical factory loads for most cartridges in both revolvers and autoloaders. If you buy a custom single action revolver from Bowen or Linebaugh, the front sight is always significantly taller than one on a similar factory model (Bowen and others typically use Ruger frames, and sometimes barrels). The dwell time in the barrel is definitely longer on a heavier bullet, and they do hit noticably higher.

    I've tried light bullets vs heavy bullets in a Ruger Vaquero (fixed sights) and in order to get the poi to equal poa I needed to increase the bullet weight to bring the poi up from where the gun was shooting low the lighter bullets.

    I typically reload 255gr hardcast LSWC bullets for both my G21sf and G37 (they work great in the 45gap, but aren't moving that fast). The 255gr bullets do shoot higher than 200gr or even 230gr bullets out of either gun, but the difference much less significant than it is with a revolver.

    I believe two factors create this difference.

    One is, as stated above, the fact that the full impact of the round going off is delayed and attenuated to some extent in an autoloader by the very nature of the slide/recoil spring/barrel interaction. The recoil is transmitted over a longer period of time, and in a gradually increasing fashion thru the recoil spring first and then the barrel stop/slide impact on the frame. Neither component transmits the full recoil impulse instantly or entirely like you get with a revolver where the case head is in direct contact with the frame immediately upon cartridge ignition. Plus, an autoloader distributes the impulse over a couple of points on the frame (the spring bearing point, the front of the frame where the slide impacts, the barrel connection or stop location, and thru friction on the slide rails). With a revolver the impulse is focused on the rear face of the frame, and specifically over the area of the head of the cartridge.

    The other factor is that a revolver typically has a higher bore axis than a Glock, or most typical autoloaders. The very nature of the single action revolver grip creates a rolling action under recoil (uless you are using a bisley grip frame). Some of the new polymer revolvers have altered the geometry of the frames enough to lower the bore axis, but whole weight distribution and recoil impulse location is different.
  14. M&P15T

    M&P15T Beard One

    Apr 7, 2011
    Arlington, VA.
    What was most interesting to me, from the first video, was the firing of the AR/M4/M16. When the bolt returned to battery, it actually bounced a bit against the breech face before going into full-lock.....

    Kinda makes you wonder about the possibility of an out-of-battery shot, especially with a select-fire AR.
  15. That is great footage to see how the bullet is either pushing air and/or gases escaping.
  16. Yes, I agree. Thanks :)
  17. DreamWeaver88

    DreamWeaver88 ...............

    Mar 10, 2001
    Southeast Michigan
    Yeah, that's what stuck in my mind also....the bolt bouncing back a bit. Weird.

  18. DJ Niner

    DJ Niner Moderator

    Feb 13, 2001
    North-Central USA
    The bolt carrier bounced, but given the amount of movement shown, the bolt itself probably didn't move at all. On most AR-style weapons, the bolt carrier has to move about one-eighth of an inch rearward before the unlocking sequence even begins. You can watch this by turning your (unloaded!) AR-style rifle upside down, with the bolt in the forward/closed position, and looking into the magazine well. Looking at the front edge of the receiver, where the feed ramps are located, you can usually see a tiny part of the bolt body itself between the receiver and the bolt carrier (you'll need good lighting conditions to see this). If you slowly retract the charging handle, you'll be able to see when the bolt begins to rotate, starting the unlocking process, and on most weapons, you have to move the carrier 1/8th inch or more before the bolts starts to rotate.
  19. M&P15T

    M&P15T Beard One

    Apr 7, 2011
    Arlington, VA.
    Excellent point!!:supergrin: