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  1. #1

    Low Bore Axis--how important is it?

    New forum member here, and I sure hope I'm not opening a big can of worms with my first post (I did at least do a search first )

    Full disclosure: I've been a "1911 guy" for a while now. However, I recently had a revelation when I bought a 4" N-frame 45 acp revolver as a "fun gun". The revolver was supposed to be a range gun that would let me shoot my 45ACP handloads without me having to then pick up a bunch of cases . Anyway, what really surprised me about the revolver was how much less muzzle flip I was getting using the same 45acp loads as in my 1911. Using a high-hand hold and magna grips, the revolver's front sight would barely move off target after each shot and it ended up that I could not pull the trigger fast enough for me to loose control of the muzzle!

    No doubt about it, the wheelgun was easier to control and I suspected that the difference had to be from the lack of a recriprocating slide or from a lower bore axis (or both).

    So, I got curious about bore axis heights, and started using photos from the internet to measure bore axis heights on various guns. I first scaled all the photos using their barrel lengths, and then measured the distance from the bore axis of each gun to what seemed like the highest point of control for the firing hand. On autoloading pistols this highest point was taken to be where the tangential slope of the tang exceeded 45 degrees (ie, when the tang "flattens out" to the horizontal). On revolvers the highest point was taken to be that of the highest point of contact attainable along the backstrap. Now, I'm completely willing to conceed that this might not be "the" best way to estimate the height of the bore axis with regard to the shooter's hand (there might not even be a "best" way). But it is at least a consistent way to measure.

    Here are some bore axis height measurements (in inches):

    Sig 226 1.44"
    M1911 (GI spec) 1.33"
    HK P30 1.25"
    1911 (beavertail safety) 1.2"
    S&W M&P40 1.08"
    SA XDm 1.05"
    Walther PPs 1.00"
    Glock 19 0.89"
    Steyr M9 0.85
    S&W N-frame (highest possible grip I can get w/ magnas) 0.85" (!!)
    Ruger LCR 0.80"

    Now that all that's done, I'm still left with the question of exactly how important bore axis height really is? Lots of gun board folks say that it's a meaningless measure and that differences on the order of a few milimeters have little bearing on how controllable a gun will be. Intuitively it makes sense to lower the bore as much as possible, but is there a point of diminishing returns?

    What I do know is that I'm suddenly thinking hard about the Steyr and the Glock (and I thought I had sworn off Glocks for good )

    What do all of you think about the importance of bore axis height when it comes to shooting for speed? Over-hyped or of critical importance?

    Thoughts appreciated!

  2. #2
    I've found no consistent effect of bore height.

    The problem in sorting this out is that you'd need two otherwise identical pistols with different bore heights. Comparing different pistols with different bore heights is meaningless due to multitude of other factors that you can't correct for.

    I don't care about perceived muzzle flip - the distance traveled by muzzle is widely considered irrelevant. I do care about my timer's data. According to my timer, I get best splits on high-probability targets with my lowest-bore pistol, but I get best splits on low-probability targets with a pistol that has a highest bore axis. Go figure.

  3. #3
    Site Supporter
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    Slide weight, caliber, and recoil spring play enough into it to think that the number might mean less than what people think.
    Think for yourself, question authority
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  4. #4
    Banned
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    DFW, Texas
    Interesting thread, though I have to question some of your data. Is the XDm really lower than the M&P? That seems wrong to me. You might also consider that the front sight on the revolver is easier to track because it's not reciprocating on a slide. You ought to try shooting the guns back to back, and maybe videotaping from the side to see which has more muzzle flip.

    Also, could you take a look at a few other guns and add them to your list? How about the CZ Shadow? People are always saying it's lower than the Glock 17, but I own both and the Glock seems lower.

    Anyway, my personal opinion is that all things being equal, a low bore axis is better than a high one, but it's certainly not the whole story. In addition to what others have said, I'll add that the shape of a grip makes a huge difference for me. I find that the more real estate there is for both hands to really clamp on, the better I'm able to control recoil.

  5. #5
    I enjoy better recoil control with my G19, over a pistol like a Sig P226. Low bore axis is an attribute that helps to get back on target a bit faster.

  6. #6
    S.M.E.
    Join Date
    Jun 2011
    Location
    FL Space Coast
    I have found that it means far less than I used to think it did.

    When I was bouncing back and forth from a P226 and a G19 I shot nearly identical FAST times and Dot Torture scores as long as I didn't do anything stupid.
    My first exposure to the P30 had me ruminating that "If only the bore axis were lower, that would be a really nice pistol!". As it turned out, it's relatively high bore-axis did not turn into uncontrollable recoil, but rather perfectly within the acceptable 9mm category.

    It is undeniable that when comparing two levers with the same forces and weights involved, the longer one will out perform the shorter one, but with all the variables in handguns along with modern grip/stance for recoil management/sight tracking, it's really a red herring.

  7. #7
    Member
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    Feb 2011
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    South Central NJ
    Personally I believe as the shooter becomes more proficient the less effect low bore axis has on recoil (or maybe we should call it recoil recovery since the physics of the actual recoil of the gun remains the same no matter who shoots it). With regards to the OP. I think the reason he felt less recoil from his N frame revolver was that the majority of the weight sits out in front of the pivot point/Grip. With the revolver you have those 6 heavy 45's sitting out there plus the added weight in the cylinder. With the 1911 those 7 45's are actually sitting where the gun pivots during recoil and doesn't help dampen the recoil as much.
    Scott
    Only Hits Count - The Faster the Hit the more it Counts!!!!!!
    Stephen Hillier - "An amateur practices until he can do it right, a professional practices until he can't do it wrong."

  8. #8
    STAFF
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    Feb 2011
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    Virginia
    Quote Originally Posted by Failure2Stop View Post
    My first exposure to the P30 had me ruminating that "If only the bore axis were lower, that would be a really nice pistol!". As it turned out, it's relatively high bore-axis did not turn into uncontrollable recoil, but rather perfectly within the acceptable 9mm category.
    I had the same experience.

  9. #9
    Member
    Join Date
    Apr 2011
    Location
    NJ
    All else being equal, it will be to your advantage to have a lower bore axis. If you could draw up the perfect pistol in Utopia, then you should add a lower bore axis.

    In the real world, where nothing is otherwise equal, there are other things to consider and it only becomes part of the equation for which pistol makes a good fit for you. Especially in 9mm, it's not as big a deal. I'm no master of recoil management. I've got small wrists and an injured left wrist, yet I do fine with my HK P2000 9mm. You move up to .40, and the pistol I prefer is a SIG P229.....go figure. Even higher bore axis. There's obviously something else going on......

  10. #10
    Quote Originally Posted by Comedian View Post
    I enjoy better recoil control with my G19, over a pistol like a Sig P226. Low bore axis is an attribute that helps to get back on target a bit faster.
    It has much more to do with the shooter than the pistol. Work on your grip strength and technique and the differences will even out for you. I'll admit that a gun with a higher bore axis is less forgiving of a weak grip than one with a lower bore axis, but even SHO or WHO I have plenty of control over my SIG.

    Here's a vid of me shooting my P226ST with factory 9mm 124gr Federal American Eagle ammo. The fact that it's a stainless frame really doesn't make all that much of a difference, I can shoot my alloy frame gun the exact same way.



    I can't see all that much muzzle flip. Look for videos of Ben Stoeger shooting, he's much better than I am and shoots a Beretta, another pistol with a high bore axis. I'm sure if he felt that that slowed him down, he'd jump platforms, considering his lack of sponsorship and his substantial dedication towards improvement.
    Last edited by DonovanM; 08-15-2011 at 10:51 AM.
    All I know is that I know nothing. - Socrates

 

 

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