IMG_20160308_132236

Robert Farago asks: “What exactly does it mean to have a high or low bore axis? What effect does that have on shooting the gun?” Great question, Robert! Bore axis has a huge impact on how a handgun shoots, and understanding that concept will give you a better idea which firearm best fits your needs . . .

AxnsMeqCAAEOG6S

Every semi-automatic handgun on the market works in pretty much the same way: there’s a barrel that stays more or less fixed in position, and a slide that moves back and forth in order to eject the spent cartridge and load a fresh one into the chamber. As always there are exceptions to the rule, but 99% of what you’ll find out there operates this way. The guns are designed so that there’s enough space between the top of your shooting hand and the bottom of the slide that the slide shouldn’t interfere with your fleshy bits. Every so often a gun manufacturer will cut that margin too slim and the slide will “bite” the webbing of your hand while moving, a phenomenon known as “slide bite.”

NOTE: Bore axis is also applicable to revolvers, but the best illustration is in semi-auto handguns.

The phrase “bore axis” in this context refers to the relationship between the barrel of the handgun and the shooter’s hand — “high” bore axis means that the barrel is positioned well above the top of the hand and “low” bore axis means, strangely enough, that it’s closer. Although no actual definition exists for the difference between the two, an “I know it when I see it” approach is usually used to differentiate one from the other. The common question at this point is, if slide bite is a potential issue, then why bother making the bore axis low in the first place? The reason is simple: recoil management.

An ideal handgun would place the barrel of the gun directly in the middle of the shooter’s grip in the crook between the thumb and forefinger. This would allow the recoil from each round to be directly absorbed back into the hand. But since the slide would have nowhere to go to cycle the gun that’s a tough design to pull off. Instead, the barrel and slide are typically positioned above the grip to allow that slide to cycle unobstructed. That’s good for manufacturing, but that can be bad for perceived recoil and speed on the range. Here’s why:

A classic example of a “high bore axis” handgun is the SIG SAUER P226 (pictured above and in video here). The barrel is positioned well above the top of the shooter’s hand allowing the slide to cycle with ease, but that same position means results in more actual and felt recoil.

Just like if you were holding one end of a lever, the same weight placed one inch away feels much lighter than if you placed it one foot away. The longer the lever, the more perceived force for the same weight. In our example here, the relatively high bore of the P226 means that the recoil of a standard 9mm round feels more stout. The lever in this example is the distance between the center of the barrel and the top of the shooter’s hand.

StrikeOne_bore-axis

The Arsenal Strike One may be the best example of a low bore axis handgun on the market. The entire gun is designed to keep the bore of the gun as close to the top of the shooter’s hand as possible As a result that lever effect is reduced and the perceived recoil is much lighter. Less recoil means that the gun is easier to get back on target for follow-up shots, and is much easier to handle for new shooters.

In short, the lower the bore axis of the gun the less perceived recoil is felt by the shooter. Even though you’re firing the exact same cartridge with the exact same recoil, one feels lighter because it’s exerting less leverage, snapping your hand back (and your sights off target) less. Sure, you can train to get your high bore axis firearm back on target quickly, but why make shooting harder on yourself if you don’t have to?

RAP-height

[Email your firearms-related questions to “Ask Foghorn” via thetruthaboutguns@gmail.com. Click here to browse previous posts]

Recommended For You

43 Responses to What Does ‘High’ or ‘Low’ Bore Axis Mean? Ask Foghorn

  1. That’s what I love about my CZ P09. It’s low also and feels a lot milder even with +P loads.

    • 5.7 also has the best capacity on the market for a full size handgun with standard size mags. You are correct though, that thing kicks…like a fly.

  2. Nick, you didn’t mention that any technique which can be applied to help reduce flip in a high-bore-axis firearm can also be used with a low-bore-axis handgun, so the lower bore axis will ALWAYS have less flip in guns of the same caliber and similar weight.

  3. Maybe I’m doing it wrong but I shoot “high bore axis” (Sigs, XD’s, 1911’s) guns better, faster, more accurately and with more consistency than I do “low bore axis” (Glocks, M&P’s) guns.

    I’m probably doing it wrong.

    • Me too. The gun I shoot most accurately and fastest is a sig p229. Perhaps I’m doing it wrong too.

        • I think more people would be Asking Foghorn if the forum weren’t quite so awful. I tried to participate, but it was extremely buggy and basically impossible to use on mobile.

          If they wanted to run the feature more regularly, they could have a weekly post (or whatever frequency) that would be open call for Foghorn questions. Sort of like the caption contest. That way, there’d be a regular stream of questions for Nick to draw from, and site users would know that maybe, say Sunday afternoons, they’re going to get a chance to drop a question into the mix.

        • I think more people would be ‘asking Foghorn’ if he didn’t post things like telling people not to engrave Form 1 items, prompting David Goldman to follow-up with an article titled “Gun Trusts: Engraving Requirements and believing what you read on the Internet”.

      • IF you are gripping the gun hard enough and consistently enough, and it is aggressively enough stippled, that it does not move at all in any other direction than straight up and back; IOW you’re fast enough to do well at gun games, lowering your bore axis will at some point help.

        If you are amongst the remaining 98% of us, trading the very predictable and repeatable straight up (and down) flip of a Sig or other similar design, for movement that depends on exactly how you hold the gun in relation to bones, fleshy parts etc of your hand, is probably at best a wash. Certainly so with 9mm ammo for most normal sized people firing full sized guns.

        Comparing a Sig to a Glock (or other plastic gun) isn’t really fair to the latter, as a corresponding classic Sig is generally 40% heavier. The new P320 is more even for even. Full size, all steel, $3500 1911s (middle of the road bore axis) are an even less fair comparison, for reasons of weight, trigger, and the absolutely incredible, velcro like, stippling jobs the best 1911 smiths are applying these days.

        In general, the obsession with bore axis in some quarters of the handgunning public, is at best insanely exaggerated. Kind of like latching on to the aerodynamic benefits of tailfins on an old Cadillac. There’s probably something to it, but the reason it got popular, is because it allows the intellectually lazy to latch onto some sort of sciency sounding simple “explanation” for something, that in reality is infinitely more complex.

        Of course, it also allows hucksters on the manufacturing side a quick way to slap together something that is ostensibly “better” than what else is out there, simply by overfocusing on one, rather irrelevant aspect of a gun, which with striker guns are almost trivially easy to get as low as one can go.

        Grip shape, grip angle, trigger, how well the grip shape is matched to trigger weight and pull length etc., are much more important factors than simply how much polymer has been dremeled out of the back of the grip. And even the above factors, more than anything, come down to simple familiarity.

        • So, to be clear, when you say it’s not fair to compare a SIG or steel-frame 1911 to a plastic-framed Glock, it’s because you are claiming the SIG and/or 1911 has LESS muzzle flip, primarily due to their increased weight? Is that what I read, above?

        • Yes. Like for like, heavier guns will exhibit less felt recoil. There are a myriad of other factors coming into play as well, bore axis one of them.

  4. Everything else being equal, yes, bore axis has an effect. However, making everything else equal is quite troublesome. For example, the P226 mentioned will have a heavier slide and frame than the Arsenal mentioned. This will absorb felt recoil. Additionally the Arsenal doesn’t use a standard Browning action. I haven’t shot one, so I can’t say whether the system used mitigates felt recoil or exacerbates it. Add in recoil spring strength, cocking action, tightness of tolerances, lubrication, grip…the list goes on.

    Bore axis can have an impact, because physics. But there’s other factors in play at the same time. And, for any leverage bore axis plays on recoil also comes into play as the pistol returns to battery. Because physics.

    So while bore axis certainly exists, I am skeptical as to the impact. You were talking about doing videos…maybe TTAG do a video a la Mythbusters to find out the actual effect. The problem will be accounting for other variables.

    Personally, I call bore axis LGS BS. But I’m open to the idea that I could be wrong.

    • Well said, and excellent points.

      The problem is trying to distill the totality of a ‘design’ down to one (or just a few) element. The same problem exists when talking about boats, for example. Picking a handful of parameters and trying to encapsulate the gestalt of the whole is impossible.

      So, your point “However, making everything else equal is quite troublesome” is exactly the issue. If EVERYTHING else is equal, you are talking about the SAME GUN and a comparison is moot.

      My approach is merely phenomenological: just shoot this gun and that gun and see which I like better. “Why” doesn’t really matter. Whether or not it fits some oversimplified model of which “should be” better doesn’t really matter.

      At the end of the day, the “whole gun” is what I’d shoot, not a single parameter or even a small set of parameters.

    • There are a handful of things that can lead to muzzle flip — the action type, recoil spring type and stiffness, slide weight and length, hammer/striker spring strength, and more. However, I do agree with Nick that it’s fair to generalize that a high bore axis pistol is going to have more muzzle flip than a low bore axis pistol. Everything else may not be equal, but it’s usually pretty close when comparing guns in the same size category. E.g. the last slides I weighed were the Ruger American to compare it to a Glock 17… 353 grams vs. 358 grams, respectively.

      There’s a lot of subjective and personal stuff that affects control and perception of recoil, like hand size and ergonomic preferences (e.g. grip angle, shape, texture), too. But a higher bore axis does give the energy of the slide more leverage over your hands/wrists and applies more torque to them. It just does. Other differences may compensate for and offset that to varying degrees, but the fact will always remain that lowering the bore axis from there will still have a very direct effect on reducing muzzle flip, which affects perceived recoil.

    • Agree, all else being equal, low bore axis does have an effect. But all else is never equal. I love my P09, but the difference between that and say an XDm, Glock, FNX is nominal. I think some people puke a little when they see things being exaggerated. Does it have an effect? Yes. Is it a profound effect? No. All of the other variables factor in just as much, if not more.

      Now… having said all that 🙂 If PMG will ever actually ever start shipping the new Stryk A (with the stippling option and the flat trigger as was displayed at Shot), I’ll be in line for one to give it a try.

  5. While only semis will suffer from slide bite, my understanding was that bore axis is an issue for all handguns. That was the impetus behind the Chiappa Rhino. The article is really focused on semis and doesn’t mention revolvers at all, though.

    I guess I thought wrong?

    • No, you have it correct.

      Besides the Rhino, there are very high-end match pistols for an Olympic discipline called “free pistol” where the bore axis is basically in line with the ball of your thumb as it sits in the grip. Look for pictures of the following pistols:

      Vostok TOZ-35,
      Hammerli FP60, FP10, and the older 102 to 107 series,
      Pardini FPM

      There are others. I’m just giving you three families of free pistols so you can see the similarities, and how they put the bore axis directly in line with the ball of your thumb while it is in the grip.

      Your mission, should you choose to accept it, is to use a single-shot, falling block pistol (of the sort I just enumerated above) and put 10 shots of .22LR into the 9-ring on a paper target, 50 meters away. The 9-ring is about 4 inches in diameter.

    • You are correct – for an article leading into a discussion of bore axis, the start of the second paragraph is rather misleading. Bore axis applies to all handguns (and arguably all held firearms). It makes the most sense to talk about this in terms of handguns, as the pros/cons of a bore axis on a shouldered firearm will be entirely different and have a lower impact on the person holding the firearm.

      As mentioned, revolvers have been manufactured to fire from the lowest cylinder for this reason – Chiappa, Mateba, etc.

      The other point needing some clarification is:

      “An ideal handgun would place the barrel of the gun directly in the middle of the shooter’s grip in the crook between the thumb and forefinger. This would allow the recoil from each round to be directly absorbed back into the hand.”

      This is arguable, and depends where you want the recoil to ‘go’. In a perfect world, the bore would be inline with a locked wrist, elbow and shoulder… and your shoulder would extend out directly from your center of mass. This is obviously impossible, but having the bore extending from between your index and thumb is still going to put the flipping impulse into your wrist. If you want an example of a bore axis that is about as good as it gets on a handgun, look at Olympic-style match pistols (such as a Steyr Match FP .22LR).

      • That’s true. Physics applies to everything, any handgun or rifle, and your body. Even without a gun, just take a standing shooting stance and pretend to shoot with your finger… You will see that your thumb is above the center of your wrist, and your shoulder is above your center of gravity. In theory, for minimum flip everything has to be as close to center of gravity as possible. That also explains why shooting prone is the most stable.

  6. Another interesting example is from the world of revolvers, since bore axis applies to a degree there as well. The Chiappa Rhino fires from the six o’clock cylinder, as opposed to the twelve o’clock in the traditional revolver design. That puts the bore axis between the thumb and index finger, rather than a couple inches above the hand. From what I hear, it makes the Rhino more controllable compared to similarly sized revolvers.

  7. When it comes to heavy recoiling handguns a high bore axis is your friend, hence the scarcity of magnum semi-auto pistols other than the 17 pound Desert Eagle. A low bore axis on a 9mm reduces muzzle flip and allows you to get back on target for quicker follow up shots. However it pushes most of the recoil staight back into your hand. Revolvers have a very high bore axis (except for the Chiappa Rhino) so most of that energy is converted to rotational force (muzzle flip). You can forget quick follow up shots with a .44 magnum, but a low bore axis would result in some very short range sessions.

    • Indeed, and some young(er) shooters are discovering exactly this issue with high powered rifles.

      If you look at high power (I mean “African Big Five type rifles, ie, .375 H&H and up in recoil) rifles, you see that they have a significant drop at the heel, and they use either a Monte Carlo buttpiece, or they have the “hogback” type of drop that European (esp. German/Czech) guns use. By putting the bore axis above the point where the heel mounts to your shoulder, the rifle tends to have lots of rise as the moment arm rotates upward around your the heel of the butt. Make the rifle weigh about 10 lbs and you get significant use of the recoil kinetic energy to lift the gun, rather than just shove straight back into your shoulder.

      Meaning: the straight-comb AR-15 type stock is a horrible configuration for a high-recoil cartridge.

      • It would make sense that recoil acts in the same manner whether you’re shooting pistols or rifles. I don’t have any experience shooting dangerous game rifles, but one observation from shooting 3″ shotgun slugs from a bench – it really, really sucks. When you’re standing the recoil not only has to move a 6-10 pound gun, but 30-50 pounds of shoulder as well. At the bench you’re just leaned forward forcing your shoulder to take the full force of the recoil. It’s a similar situation with handguns in that a low bore axis pushes the recoil into your braced hand, whereas a high axis flips not only the handgun but your hand, wrist and with really heavy recoiling revolvers your whole forearm. And the absorption of the recoil is spread out over 6″ or a foot of motion instead of a fraction of an inch.

        Of course in extreme situations, the last bit of recoil is absorbed by the shooters forehead…

    • I assume that’s why the Jericho .45 is so unpleasant to shoot? It’s based on the CZ design, and I find that the metal frame just batters the web of my hand between the thumb and trigger finger. I shoot a variety of .45 and 10mm handguns, but I find that the Jericho hurts like no other .45.

      • It may be the girth makes you wrap around more taking the recoil more towards your thumb knuckle than you are used to…

        A the barrel should align down your wrist to your elbow. If it’s shooting off to the side when you have pad of finger on trigger, girth is to large.

        I’ve got small hands and small gloves. So I’ve personally studied the issue…

    • “When it comes to heavy recoiling handguns a high bore axis is your friend,…”

      When I had that Super Redhawk in .44 mag, I really hated that muzzle flip. Having that relatively heavy pistol scope on that 7 inch barrel really helped to tame it.

      Instead of hating the muzzle flip, it looks like I should have just been learning to just ride with it and let the muzzle rise soak up some of the recoil.

      Now I hate even more having trading that hand cannon off for a (embarrassed mumble)…

      Live and learn, *again*.

      • The good news is that Ruger is still making the Super Redhawk.

        My philosophy with the .44 mag and up is just to let the recoil happen.

  8. A deeply undercut stock that places the strong hand closer to the center of the slide does wonders to mitigate recoil and control muzzle rise. It doesn’t take much to make a big difference.

    The late, lamented Caracal, aside from having a very low bore axis, also had this deep cut. As a result, it shot more like a pussycat than a wildcat.

    Ruger’s new American Pistol incorporates a barrel cam that supposedly reduces recoil and muzzle flip by controlling rearward movement of the slide when firing. Not having tested the American, I don’t know if this cam works, but it should.

    In short, a low bore axis, without more, is better than a high one, also without more, for recoil management. However, recent innovations may make bore axis discussions of academic interest only within the very near future.

  9. The concept in play here is known in physics as Moment (or torque, when dealing with angular motion) and can be defined as τ=r*F.

    *THE MORE YOU KNOW*

  10. Is it the bore axis per se or is it the height of the center of mass of the slide and the height of the recoil spring guide rod versus the positioning of the web of the hand?

    Not a physicist so i cant elaborate on the reason. But it feels to me, that when the gun recoils, the slide imparts a torquing motion around the base of the guide rod and this “twisting” is what causes the recoil transmitted to the hand.

    Someone enlighten me

    • It’s a mix of many things, but it’s mostly the center of the bore line. That’s because it’s the acceleration of the bullet plus the explosion of the gasses that is pushing back on the gun. The actual rearwards motion is caused by that, which is always going to be centered in the bore. Doesn’t matter if anything actually reciprocates (e.g. a revolver still kicks and a lower bore axis makes a difference in reducing muzzle flip there as well). But once you add a reciprocating slide that hits home at the back of its travel, etc, then you’re adding further variables as well like the center of mass of the slide compared to the height of your hands (its polar moment of inertia compared to your hands, basically). But mainly I do believe it really is bore axis that’s the primary factor.

    • What you’re getting at is the importance of the mass distribution in perceived recoil, and you’re quite right to bring this up. Bore axis, in this article and among enthusiasts, is seemingly used with an implicit assumption that the difference in mass distribution between guns is negligible or that the moment arm alone is a dominant factor in recoil perception; the former might be okay with substantially similar guns (meaning, Glock vs. XD, not Glock vs. Sig), but the latter is a gross oversimplification and seems likely wrong to me.

      I can say that bore axis is *a* factor in perceived recoil.

  11. The new Kalashnikov PL-14 has the lowest bore axis I have ever seen, besides maybe a Chiappa Rhino, too bad nobody is distributing them in the states…

    • I was unaware of that pistol, very cool. It reminds me of the Steyr M9. To me the Steyr seems to have a fairly low bore-axis, and happens to be one of my favorite handguns for several reasons; one of them being that the M9 makes it look like I’m a far better shot than I actually am.

    • Oh that is one slick looking pistola. Very video game looking, like something from Perfect Dark. It’s a shame we won’t be getting any here in the states. Thanks Obummer.

  12. Higher bore axis = “flipier” for want of a better term
    Lower bore axis = more “felt” recoil.

    All in all I prefer a higher bore axis than one that pounds on the nerve cluster in my right hand.

  13. Even with that stupid ass light under the barrel, the 226 was kicking like a mule!! And that’s a pissy 9mm!! Can you imagine in a .45? Oh, wait, I can!! ‘Cause I just bought the new, sort of, Sig P320 Compact .45. It is, without a doubt one of the heaviest slides I’ve ever felt on a Semi Auto handgun!! Unless the 9 round mag is in it, it’s so top heavy you can’t believe!! And even with a full mag, it just barely balances it out!! And of course, since I bought it, sight unseen, so to speak, I cannot get money back!! I based my purchase of the .45, on the feel I got for the 320 9mm. That one felt good, so I assumed, and we all know what that does, the .45 was gonna be the same exact way!!! NOT!! I took it to the range the day after I got it, and it kicks and does muzzle flips, I thought it was trying out to be in the circus!!! So now, a gun that I was so excited to get, I don’t even care about!! In my mind, it’s become a $500 paperweight!! I should’ve just stuck with my Sig Ultra Compact 2 Tone, 7+1. But since I customized it, I wanted something that I wouldn’t lose any sleep over, if it got confiscated after a shoot out with a bad guy! Because down here, in South Fucking Florida, the odds of you ever getting your gun back, are pretty much non existent!! So now it’s back to square 1 to find a carry gun!!

Leave a Reply

Your email address will not be published. Required fields are marked *