Hand Length to Gun Fit: A Case Study: Analysis and Conclusion (Part 3)

[Doc_Glock]

Still working to boil this down.

I collapsed all the words into this, and incorporated the concept of "ideal fit" (I went with GC to HL (92%), instead of HL to GC (108%). Seemed to fit the words better. All these cell texts might serve as captions to the front side of the "Handout" (i.e. graphic aid chart) in callout boxes, maybe. I also used "idea" to convince myself to remove the "you can use any gun smaller than your hand length" which is of course rubbish - you need a gun that fits, not too large or too small.

(Funny, the "ideal" magic ratio of 92% (inverse of 108) is almost exactly the original grip circumference values..and is consistent for all the sizes. Huh. It's almost like some kind of odd Fibonacci Sequence.

Rich: I sadly have not followed these threads enough which is unfortunate because as a Hand surgeon and shooter you would think I would be more interested.

Anyway:

Two measurements I think are important:
1. trigger reach for index finger.
2. Grip circumference for the gripping fingers.

Essentially the hand needs to do two different functions and the gun size affects each one. Thankfully hands are amazingly adaptable so we can shoot all kinds of different guns well with a little practice.

For me personally I want the largest grip I can get for the gripping surface while still reaching the trigger.

Also: finger flexion follows a fibonacci sequence:

[RJ]

Aha! Fibonacci! I knew there was some value in staying awake in math class.

Kidding. Thanks @Doc_Glock, very interesting stuff.

[RJ]

As a short footnote to this whole study, @GJM's thread on Macro vs. Glock 19 size got me thinking about a short detour I hadn't done in the original work. It is outlined in this thread:

https://pistol-forum.com/showthread....ne-or-mid-size

So what I realized was I had never gone back and compared my "categories" by size (or Grip Circumference, more accurately) with what actual pistol maker were using for their nomenclature.

So I took a quick look at several; initial results below.

First, auto-loading pistols:



I am not as familiar with revolvers, but I did want to include a sample, so I picked S&W (please let me know if anything in this is incorrect, I am not much of a wheel-gun guy.)



And lastly, as a sort of control, I included the same data from the Grip Survey tab on my study, arranged in similar fashion:


Looking at all this, I noticed a few things. Glocks for instance, all seem to have the same Grip Circumference, but they classify pistols not by frame size, like you might think, but by slide length. Sig has a completely unique category, "Carry", that's not apparently used by anyone else. And a good portion of manufacturers simply don't classify their guns by size, at all, leaving you to figure it out.

Anyway, just wanted to read this into the study, as it were, for the record.

[BN]

A thought on your revolver listing.

The K and L frames might be switched. The K has a smaller frame than the L, but the L was designed to have the exact same grip size and distance to the trigger as the K-Frame.

[RJ]

I have a second footnote to add:

After the initial study was concluded, I kept asking on various forums for additional hand/grip data, from owners. This ended up with me getting a total of 27 separate data points.

Averaging the data across the folks who reported data for at least one (sometimes more) of their guns, I plotted their grip size average ratio to their hand length, then added a trend line:



So what you are looking at is a chart where hand length in inches is across the bottom (X), and for the Vertical (Y), the ratio of GC to HL. What's interesting to me is that the notion that folks with smaller hands preferred ratios almost exactly the same as their hand size seems to be confirmed.

As hand sizes got larger, their owners GC to HL ratio got generally smaller.

OK I think that's it. As you can tell, I like messing around with this stuff.

[sickeness]

I appreciate the effort that you put into this post but I am sure that there are many nuances involved in hand fit that can't be numerically dissected and evaluated. For example I have very small hands but find that although the VP9 has a small circumference, it does not fit my hand at all, while a beretta with a large circumference fits my hand quite well. The grip shape and angles play a much larger role in comfort and control than the physical grip size.

[sickeness]

More thoughts:

Your study appears primarily based on the assumption that the primary hand should have a full grip around the circumference of the gun, which I feel is deeply flawed.
You are equating the assumption of proper handgun fit which is a complex concept to that of glove size which is not. A glove either fits or it doesn't, a handgun may fit in some ways leading it to be disadvantageous in others.

As stated before by other posters, one tends to shoot the best with the largest gun that fits their hands. I appreciate the effort and mathematical analysis that you put into it, but have to say that I strongly feel that in total it is a wasted effort because your study is based on the aforementioned flawed assumption. The important factors at play in performance based on grip I would say is to find the grip where you can both comfortably reach the trigger and have enough surface area to engage the maximal surface of both palms. In fact I find that not having a full strong-hand grip and having adequate room to seat my support hand around the gun is a major factor in establishing recoil control over the pistol.

Sample size of myself but according to your study based on my hand size (7) I should be shooting a G48 or P365 sized gun, I own both of these guns and cannot shoot them well at all and find them if anything way too small to have a proper two-handed grip. Having small hands, despite popular belief I have been told over the years, I find that I shoot best with a 92FS which is a gun considered to have a extremely large grip. The contour of the grip I find allows me to have full contact around the circumference while having a trigger that is reachable. On the other hand I cannot shoot a CZ75 for shit because although the grip is smaller, the trigger reach is excessive.

[John Hearne]

First, I can't believe I had missed this wonderful data drive thread until today.

Second, I think that you have a great "starting point" for appropriate gun fit. I checked both my hand and my wife's hands and found the chart holding up pretty well.

Third, the next step would be to calculate ideal grip length. Just by serendipity, a P320 Compact length with magazine inserted is as small of a grip as I can shoot well. Someone with a different hand size would get a different result. I wonder how strongly the palm to finger tip measurement correlates with other hand size dimensions. The other issue I see is that palm to finger tip doesn't account for variations such as long palms and short fingers or long fingers and short palms.

FWIW, when I offer my Who Wins lecture to groups with lots of firearms instructors, the section with the most response/feedback is the one on gun fit. For years, people struggled to shoot guns that were too big for their hands. In recent years, with the rise of micro-9's, I've seen the problem reverse - people shooting guns too small for their hands. The Sig P365 fills a very nice niche for a really small gun that has a lot of capability. The problem is that the gun is too small for most males to shoot well. I only half joke that the P365 turns 9mm into 40 S&W.

Regarding an earlier observation about the guns being too large for the population's hand size, Tom Givens has quipped that the Glock 17/22 is too large for 80% of the public to shoot well. Once again, Tom is right....

[RJ]

A thought on your revolver listing.

The K and L frames might be switched. The K has a smaller frame than the L, but the L was designed to have the exact same grip size and distance to the trigger as the K-Frame.

Thanks! I have swapped L and K frame columns. I'll refresh the table with Colt and Ruger data soon, will be interesting to compare.

[RJ]

First, I can't believe I had missed this wonderful data drive thread until today.

Second, I think that you have a great "starting point" for appropriate gun fit. I checked both my hand and my wife's hands and found the chart holding up pretty well.

Third, the next step would be to calculate ideal grip length. Just by serendipity, a P320 Compact length with magazine inserted is as small of a grip as I can shoot well. Someone with a different hand size would get a different result. I wonder how strongly the palm to finger tip measurement correlates with other hand size dimensions. The other issue I see is that palm to finger tip doesn't account for variations such as long palms and short fingers or long fingers and short palms.

FWIW, when I offer my Who Wins lecture to groups with lots of firearms instructors, the section with the most response/feedback is the one on gun fit. For years, people struggled to shoot guns that were too big for their hands. In recent years, with the rise of micro-9's, I've seen the problem reverse - people shooting guns too small for their hands. The Sig P365 fills a very nice niche for a really small gun that has a lot of capability. The problem is that the gun is too small for most males to shoot well. I only half joke that the P365 turns 9mm into 40 S&W.

Regarding an earlier observation about the guns being too large for the population's hand size, Tom Givens has quipped that the Glock 17/22 is too large for 80% of the public to shoot well. Once again, Tom is right....

Thanks John.

I will ponder these points and maybe go back to MIL-STD-147D as a reference to see if there's any relationship between palm to fingertip and other hand dimensions.

I agree with you that Tom is usually right.