What performance level do you demand from your carry gun?

[JCN]

There are archers and there are arrows.

A good archer could still do well with unbalanced arrows, but why pick something that hampers their skill and potential unless it’s a cost or availability issue?

I think I found the limit of my carry gun (P365X with red dot).

I had been casually testing my 25 yard accuracy at speed with that gun over the past month and I was perplexed that the holes didn’t quite show up where I felt they should (using the stock barrel). I’m pretty good at calling my shots from competition so it was kind of a mind fuck.

After doing gun and barrel testing in another thread, I found pretty impressive accuracy with an aftermarket P365 barrel.



Not quite as good as an EDC X9 but I’ll take it.



I found it fairly straightforward to do the “No Fail” test at 25 yards with shots around 2 seconds per string from concealed draw.



With a very accurate competition gun with light trigger it was even easier.



I know people like to say “the gun is more accurate than I am,” but there might actually be a functional interplay where you might not want to accept less mechanical accuracy.

Interestingly, the originator of the drill, Chuck Pressburg... used a KKM barrel in his Glock when he demonstrated this test.

I’m fortunate that I train with guns with excellent mechanical accuracy for competition, but I could see a sloppy gun really messing with someone’s learning if they were trying to extrapolate their trigger press from the hole on target.

[backtrail540]

The last part resonates. Early on when shooting a p30 lem, i changed sights to a 10-8 rear and some random front that I've now forgotten. I ran that setup throughout my p30 tenure and always struggled with 3x5's at speed or 2" dots. I used a drive the dot sight picture back then. Just before selling i switched to a set of dawson fibers and all woes went away. All the sudden i hit the same targets with ease. I was running mismatched sights unknowingly the while time but being a fairly new shooter, i attributed it to my lack of skill when a large part of it was hardware.

[Default.mp3]

I know people like to say “the gun is more accurate than I am,” but there might actually be a functional interplay where you might not want to accept less mechanical accuracy.

Interestingly, the originator of the drill, Chuck Pressburg... used a KKM barrel in his Glock when he demonstrated this test.

I’m fortunate that I train with guns with excellent mechanical accuracy for competition, but I could see a sloppy gun really messing with someone’s learning if they were trying to extrapolate their trigger press from the hole on target.

There was some theorycrafting I did a couple years ago:

Larry Vickers, the tactical luminary that he is, argues for a handgun capable of a 2.5" mechanical accuracy in a 10 shot group: http://www.vickerstactical.com/accuracy.html


I do think that's not a bad standard to meet.


Intrinsic accuracy is good for any shooter, although there are obviously diminishing returns. Even if you can't outshoot your gun, you still gain accuracy overall with a more intrinsically accurate gun.

To expand a little on my previous post, I whipped up a couple of graphics in Excel. I just used a uniformly random distribution for both shooter's muzzle alignment and the gun's intrinsic accuracy. The 95% group was calculated using the STDEV.S function in Excel, and multiplying it to get 4 σs worth of distance (which I think is the correct way to do it?).

Images generated the same way I did the last batch:

@GRV also participated in the latter thread:

At a glance Default.mp3's new images seem to corroborate what I was suggesting, which is that a better shooter will always see more benefit (both absolute and relative) with better equipment than a worse shooter.


His data is looking at what percentage of shots fall in a certain size area. I think that's a pretty good model, and that's basically what I was thinking about when I posted my numbers. However, the truth is that group shooting is a different beast. For good measure I've gone ahead and done some simulations.


Like Default.mp3, I'm assuming that the shooter and the gun are each responsible for a Gaussian distribution that's roughly a certain number of inches wide and that these two distributions add (statistical independence, which seems fair for internal gun modifications).


Where these plots diverge from his however is that I've imagined that each shooter shoots 1000 5-round groups. Each group is measured in the traditional way, by measuring the furthest distance between two points. Then I plot a histogram of the group sizes and statistics for them. Keep in mind, the average size of a 5-shot group is going to be quite different than say a 2-shot group or a 10-shot group for the same shooter.


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It's not worth paying too much attention to the exact numbers for shooter and barrel precision, they are not very meaningful on their own, and it's better to think of them as placeholders for "better shooter", "worse shooter", "better barrel", and so on.


Here are some abbreviated results comparing 2" barrel to 1" barrel average 5-shot group sizes for various shooters:
3" shooter: 3.26" vs. 2.93" = 0.33" improvement (10%)
2" shooter: 2.63" vs. 2.04" = 0.59" improvement (22%)
1" shooter: 2.04" vs. 1.31" = 0.73" improvement (36%)
0.5" shooter: 1.9" vs. 1.03" = 0.87" improvement (46%)


Again, this suggests the better shooter sees more improvement regardless of whether the shooters are better or worse than the equipment itself.


My code could be screwed up, and to be honest I defined shooter and barrel precision by a hand-calibrated confidence interval that could be totally bogus. That shouldn't really effect the conclusion. But, if people want to look for errors or experiment with different group sizes, numbers of trials, and parameters, here's the python code:

import numpy as np
import matplotlib.pyplot as plt
from scipy.spatial.distance import pdist


num_of_groups = 1000
shots_per_group = 5
shooter_precision = 0.5 # inches
barrel_precision = 0 # inches


confidence_tuning = 0.3 # 0.3 -> precision = full-width-quarter-max


def cov(precision):
    return [[(confidence_tuning * precision)**2, 0], [0, (confidence_tuning * precision)**2]] 


def samples(precision):
    return np.random.multivariate_normal([0,0], cov(precision), shots_per_group)


def group_size(group):
    return np.amax(pdist(group))


def group_sizes(shooter_prec, barrel_prec):
    output = []
    for i in range(num_of_groups):
        group = np.add(samples(shooter_prec), samples(barrel_prec))
        output.append(group_size(group))
    return output




dataset = group_sizes(shooter_precision, barrel_precision)




# Plot results:


fig = plt.figure()
fig.suptitle(str(shooter_precision)+'-inch Shooter with '+str(barrel_precision)+'-inch Barrel', fontsize=14, fontweight='bold')
ax = fig.add_subplot(111)
fig.subplots_adjust(top=0.85)
ax.set_title(str(num_of_groups)+' '+str(shots_per_group)+'-shot groups\naverage group size: '+"{0:.2f}".format(np.average(dataset))+' inches, std. dev.: '+ "{0:.2f}".format(np.std(dataset))+" inches")


ax.set_xlabel('size (inches)')
ax.set_ylabel('# of groups')


ax.hist(dataset, bins=np.linspace(0,11,22))
plt.show()

If I wanted to do the actual theoretical math to verify this, which would let us remove the Gaussian assumption and get a parameter-independent result, I wouldn't be bored enough to be on PF.


But I agree with voodoo_man, it's all bullshit unless it adds up in meatspace. So, if SLG is willing to provide all the ammo, equipment, location, and and his time, I will gladly shoot 1000 5-round groups with him........for science!




ETA: The confidence interval was total BS. I retweaked it so that shooter and barrel precisions now correspond to full-width-quarter-maximum, which seems to correspond nicely to average 5-round group capabilities.

[GJM]

JCN, want to ask you something about your groups. I recall a number where you “pull one shot out.” In some 100 yard shooting I did some years back, I frequently found the first hand cycled round was a flyer relative to successive rounds. Is your “shot out” often the first one you fire?

[JCN]

THANK YOU!

Those graphs are exactly what I was feeling and seeing from my shot calling with the factory and then the aftermarket barrels with the P365.

[Default.mp3]

JCN, want to ask you something about your groups. I recall a number where you “pull one shot out.” In some 100 yard shooting I did some years back, I frequently found the first hand cycled round was a flyer relative to successive rounds. Is your “shot out” often the first one you fire?

FWIW, I've seen that before with my guns at 25 yards when zeroing freehand... so it may not be a mechanical issue. But I've seen it enough times to just kinda ignore single flyers. Seen it with rifles, too, at 100 yards, though with a can in play, there's even more variables.

[JCN]

JCN, want to ask you something about your groups. I recall a number where you “pull one shot out.” In some 100 yard shooting I did some years back, I frequently found the first hand cycled round was a flyer relative to successive rounds. Is your “shot out” often the first one you fire?

At least with this last bench rested group test, the one I pulled out was one I called out with a bad trigger press. I think it was somewhere in the middle of the group.

I haven’t noticed any consistent first shot shenanigans on drills, but will pay more attention in the future.

[MVS]

JCN, want to ask you something about your groups. I recall a number where you “pull one shot out.” In some 100 yard shooting I did some years back, I frequently found the first hand cycled round was a flyer relative to successive rounds. Is your “shot out” often the first one you fire?

Back when gun magazines were big and I devoured all of them I could, I remember reading about that. I believe it was Massad Ayoob who wrote it. At that time they used a ransom rest a lot for testing and it still happened with it. IIRC, I have slept some since the nineties.

[JCN]

Back when gun magazines were big and I devoured all of them I could, I remember reading about that. I believe it was Massad Ayoob who wrote it. At that time they used a ransom rest a lot for testing and it still happened with it. IIRC, I have slept some since the nineties.

It was interesting, I watched some videos from the ransom rest company and they were saying it was first shot settle as the grip settled into the insert under load.

[D-der]

JCN, could I inquire, do you find a reasonable improvement in barrel accuracy of the True Precision barrel over the OE Sig ?
It seems every time I check for a non threaded XL barrel they're out of stock.
Appreciate the thread and any feedback.