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Alignment index vs bore-axis height

Discussion in 'Handguns: Revolvers' started by labnoti, Feb 11, 2019.

  1. labnoti

    labnoti Member

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    On some handgun grips, your trigger finger is aligned or parallel with the bore axis whereas with another gun or grip the axis of the trigger finger is not aligned but diverging from the bore axis to a lesser or greater degree.

    With automatic pistols, the grip is most often fixed by the curve of the tang or beavertail above the backstrap and while grip side panels and backstrap inserts can change the width of the grip or the amount of palm-swell, the alignment index and height of the bore axis usually have a fixed relationship. Automatics tend to have alignment indexes that are close to parallel and fairly low bore axis in part because they do not have a large cylindrical magazine between the bore and the trigger like most revolvers.

    Some guns like the 1911 or P226 have a greater bore axis height but maintain a near parallel alignment index. An AR pistol would be an even more extreme example. Other guns, striving for an even lower bore axis can have a grip so high on the backstrap that axis of the trigger finger begins to diverge from parallel. Glock and the Steyr M9 would be examples.

    With revolvers, the size of the cylinder and frame usually determine the height of the bore axis above the trigger. It can also vary a little with the diameter of the chambers and how many are bored in the cylinder. The alignment index is somewhat determined by the shape of the grip frame and the style of grip panels or stocks. There is a lot of freedom in the design of these parts on a revolver compared to an automatic where the grip frame most often contains the magazine. There is also often a greater degree of freedom in how the revolver stocks are gripped.

    On a traditional single action grip (i.e.1873), the alignment index with most people's grip is close to parallel. The bore axis is quite high, and with most guns, the opportunity to take a higher grip is limited by the cocked hammer spur. This could be mitigated to some degree by reshaping the spur or with short-stroke parts, but as the palm begins to ride higher on the backstrap, the alignment index begins to diverge.

    With double-action revolvers like Smith & Wessons or Rugers, going from the smallest to larger frame sizes there are increasingly greater bore axis heights, but all the frames have substantially higher backstraps than the traditional single-action shape. This allows one to take a low grip and keep a closer to parallel alignment index, or to grip the gun higher on the backstrap sometimes resulting in extremely divergent alignment indices. Stocks with finger grooves tend to force a certain grip height or you suffer misaligned grooves, whereas smooth stocks allow for more freedom in the grip choice.

    I've noticed that speed gunners that seem to live for low split times tend to prefer and advise the highest grip possible. They can have the grip so high on the backstrap that they need to bob the hammer. For them, it seems that this is the only way of controlling recoil in rapid-fire where there is a power-factor requirement that can achieve the fastest times. It results in a difficult alignment index but I imagine they simply determine to overcome this with lots of training.

    Revolver shooters from other disciplines, especially those where a timer is not used, might have a different perspective.

    What is your discipline, and do your grip your revolver high with the trigger finger at a steep angle or lower and nearer to parallel with the bore axis?

    I grip my revolver so the web of my thumb just barely overlaps the very top of the backstrap. It is possible to go about a quarter-inch above the backstrap before the double-action hammer stroke begins to hit the web. I am considering the trade-offs of lowering my grip so the web is about an eighth of an inch below the top of the backstrap. This seems like a small change in grip height, but the effect on the angle of the alignment index is significant. The difference between 0 degrees and 20 degrees is not huge, but the closer you get to 90 degrees, the difficulty increases greatly. Try wrapping your hand over the top-strap and pulling the trigger.
     
  2. RevolvingGarbage

    RevolvingGarbage Member

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    I think the answer is always to do what feels best and produces the best results for a given person. I've always been partial to taking as high of a grip as possible on a revolver, though I've never owned a single action only gun.

    I've noticed with one of my recent acquisitions, an Enfield snub, that while the grip is designed with huge scalloped sections for your thumb and forefinger to rest in, I can achieve a much higher and more comfortable hand position for rapid fire by choking my hand up higher so that the web of my hand is nearly in contact with the hammer. It being a DA only revolver and firing low powered ammo, this grip is easy to maintain even firing very rapidly and it has the nice side effect of allowing the thumb to rest on the stirrup latch for less movement to execute a reload.

    With a hammerless design and especially one firing low powered .38S&W, you can get your hand in a position on the gun such that the bore is in a lower position relative to the hand than even most semi auto pistols will allow for.
     
  3. RevolvingGarbage

    RevolvingGarbage Member

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    Choking all the way up on a hammerless gun shown here:

    IMG_20190211_140735.jpg
    IMG_20190211_140821.jpg
     
  4. 460Shooter

    460Shooter Member

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    While recoil seems a bit lessened to me the higher I keep m y grip, I tend to have a cleaner and more controlled trigger stroke if I keep my strong hand a bit lower, with only the very top of the web of my hand touching the top rear of the grip, and a very strong support hand grip.
     
  5. Hondo 60
    • Contributing Member

    Hondo 60 Member

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    What works for me, may or may not work for you.

    But I also try to get a "high" grip on my revolvers.
    I also reload my own & can tailor them to my gun.
    Usually I load them kinda light, but still 700+ fps.

    .38 Spl is 800-850, so not "mouse farts" but still not +P range either.

    I think the final answer is gonna reside with doing what's most comfortable for you.
    That's the fun of shooting ... finding a gun that feels right for you
     
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  6. MrBorland

    MrBorland Moderator

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    I've never found "alignment index" to be an issue, not never heard any decent revolver shooter worry about it, nor do I recall reading any suggestion by the great shooters of of yore (e.g. Ed McGivern or Harry Reeves) that one should grip their DA revolver low to align their finger with the trigger.

    Grip your DA revolver high. You shouldn't see backstrap peeking out from under the webbing between your thumb and trigger finger. It's the shortest distance to the trigger, offers the best trigger control (particularly the DA trigger), and the best recoil management. From what I've seen, many grip their DA revolver too low.
     
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  7. forrest r

    forrest r Member

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    You want to hold a revolver/pistol so that you can pull the trigger strait back. Once the strong hand's hold is established the support hand (2 handed hold only) is brought into position. Where the axis of the bore ends up, depends on the shooter's hand size and the size of the firearm. Some use a "high mount" when using a 2 handed hold with the support hand adjusting for the angled trigger pull. Changing grips is another common thing to do to lower the axis of the bore while maintaining a strait trigger pull.

    Glad to see people still remember Harry Reeves, he represented our country well with a free pistol. Most target pistols are deasigned to have the bores axis line up with the web of the shooters hand. Then the grips are fine tuned (sanded/bondo/shaped) to fine tune the grips to the shooters hand/hold. 10m pellet pistol, 25m sport pistol & 50m free pistol with the grips customized to fit my hand.
    YyeYw7R.jpg

    I also use a contender to practice for the free pistol. The contender is heavier, the 9mm or 357 bbl/ammo combo's recoil teaches the shooter to have a good follow thru. The bore axis is higher and the recoil str along with the extremely heavy 14oz trigger teaches trigger control.
    oCLC4Gy.jpg

    Ed McGivern,
    IMHO the best revolver shooter there ever was!!! He set records with the s&w k-frames that are still there to this day that other exhibition shooters could only dream about.
    McGivern, along with his friend Elmer Keith, were instrumental in pushing the envelope in the early days of magnum revolvers. While Keith was primarily interested in hunting, McGivern was more interested in police use of the revolver. McGivern demonstrated that with proper sights and use, the 357magnumcould be used on man-sized targets at ranges of up to 600 yards (550 m). McGivern experimented with different types of iron sights including peep sights, and telescopic sights. His preferred type of iron sight for this use was a small-diameter rear aperture and a post with a gold bead for the front.

    McGivern went on to instruct police agencies, including the FBI, in his shooting techniques.
    .https://en.wikipedia.org/wiki/Ed_McGivern
     
  8. labnoti

    labnoti Member

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    The shortest distance to the trigger is a function of the grip frame. For example, with a steep backstrap angle on a Bisley-style gripframe, there is no appreciable difference in the distance to the trigger. Moreover, a gripframe could be designed to give a shorter distance at a lower grip height. But more importantly, the shortest distance isn't the ideal distance. If it were, we would be trying to make grips with shorter and shorter distances. Rather there is some ideal distance and we shouldn't assume that the highest grip is going to achieve it every time.

    A high angle in the alignment index most certainly does not give the best trigger control. Just look at the first picture in this thread. The angle of that finger to the trigger just looks horribly tortured. But if this example is not extreme enough, grip your revolver much higher than you would normally, so that the hammer spur is in your palm. Do you get good trigger control from there? With my shrouded Centennial, the spur is not even an issue, but the high alignment index is. From that high position, my finger muscles are much more effective at pulling up than they are at pulling the trigger back. It seems to me that again there is some happy medium and exactly where that is cannot be arbitrarily determined as always as high as possible.

    I do believe the highest practical grip offers the lowest practical bore-axis height and therefore the best recoil management. That much is intuitive. And I think that is the reason you will also see all those "great revolver shooters" do this is because many of them are concerned foremost with the fastest rapid fire. Certainly, most competitive revolver shooters of the present age are in sports with shot timers and they win with the lowest split times. It doesn't surprise me that a bullseye shooter writes, "You want to hold a revolver/pistol so that you can pull the trigger strait back."

    I have learned and do shoot a DA with my grip exactly as you described (no backstrap peeking above the web). But I have noticed that the high angle of alignment index this results in is one of the most profound differences between a revolver and an autoloader that I never hear discussed.
     
  9. forrest r

    forrest r Member

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    Labnoti you are absolutely correct when you write:
    It doesn't surprise me that a bullseye shooter writes, "You want to hold a revolver/pistol so that you can pull the trigger strait back."

    You really don't have a choice of a high or low grip in your 1st picture. Just not enough real estate to move your hand around much. A ca undercover does the same thing to me that is showed in your 1st picture. To get a "lower" grip I'd have to remove my bottom finger from the grip altogether. Take a picture or 2 of a high mount with a n-frame s&w where you have room to settle in.

    For games of speed I use a high mount and a 2 handed hold preferring medium sized frames. My ppc revolver built on a k-frame (model 10)
    k2b51Hx.jpg

    Custom dw's with 1 in 10 twist bbl.'s heavy shrouds and muzzle breaks setup for fullhouse 357's. These revolvers are excellent for high mounting with their backstrap design/angle and short hammer spurs. Note that the 4" revolver is setup with a trigger stop along with having a full # lighter trigger when I had the trigger work done on both of them.
    lwCejE1.jpg

    The s&w competitor isn't bad for a box stock revolver. It could use some trigger work but the stock trigger is actually pretty good and ignites everything. I do like the weights to tune the balance of the revolver. The l-frames were designed for 2 handed speed shooting with the bottom of the backstrap taking on a rounded (bisley) profile. Where the dw's are more striat back.
    TqNbjbt.jpg
    Bought that s&w 686 competitor to shoot shotgun shells with. Same rules as bowling pins except:
    12ga shotgun shells are used instead of bowling pins
    We shoot the shotgun shells at 50ft instead of the typical 25ft/bowling pin setup
    12ga shotgun shells are +/- 1" wide x 3" high so you need a good load/highly accurate load. Couple that with speed and trigger control to be able to not only hit something. Excel/win when you hit the loud button. I developed 2 different loads for that 686 to play around with 12ga shotgun shells on the bowling pin table. 6-shot test groups, not hand/cherry picked by any means. Nothing more then the test targets used that day to test loads with.
    AL4WBux.jpg

    So ya bullseye shooting strait pull and custom/hand fitted grips. Speed shooting, high mounts 2 hands and I prefer gripper grips.
     
  10. 9mmepiphany

    9mmepiphany Moderator

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    It isn't arbitrarily determined. The shortest trigger stroke is determined by the arc through which the trigger travels on a DA revolver. On most DA revolvers, the top of the recoil shoulder is in a direct line in the trigger travels arc
    While we hear this oft repeated it doesn't mean what many believe it to mean. It means that the trigger should travel (be pulled/pressed) to the rear without side to side pressure...it doesn't mean it has to be pulled parallel to the bore.

    You have to remember that many of these cliches come from the time of the 1911, or when revolvers were shot in SA. The 1911 trigger does indeed move straight to the rear, but most pistol's triggers move in an arc. If you tried to stroke a DA revolver trigger as you would a 1911 trigger, you're finger would have to slide downward toward the tip of the trigger as it moved further rearward.

    Wanting a trigger to breaks "straight to the rear" is what is causing the proliferation of straight triggers being made for polymer pistols. The sear breaks when the trigger is at 90 degrees to the bore line
     
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