Why are larger caliber guns more difficult to shoot accurately?

F

FUD

Moderator
I asked a similar question once before but I'll be more direct now ...

I have a S&W 5906 and a 4006. With the exception of one being a 9mm and the other a .40S&W, both guns are identical in shape, size, weight, functionality, etc. Yet I can shoot the 9mm more accurately than the .40S&W.

According to what other members have said in previous posts, recoil doesn't really kick in until the bullet is already on it's projected path. So, why am I more accurate with the 9mm than with the .40S&W?
 
Recoil begins to kick in the second the bullet starts to move, actually...

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Beware the man with the S&W .357 Mag.
Chances are he knows how to use it.
 
FUD, I believe in the example you used the 9 is just more inheriently accurate than the .40. But I know that was just one example.
Mike is correct in that the effects of recoil begin when the cartridge is fired long before it leaves the muzzle.
Much as we all hate to admit it we do, ocassionally, flinch in anticipation of recoil. Both perceived and actual recoil tend to be greater in a revolver than in a semiauto. For more years than I care to count I have shot nothing other than .41 and .44 magnums with any regularity. However, in spite of that I still will ocassionally catch myslef flinching. When I do I know immediately what I am doing and correct the problem.
I had noticed my accuaracy going down hill for a while when a year ago I was diagnoised with disabling arthritis and degenerative joint disease. Since then Terri got her first gun, a Taurus PT92, 9mm. I have shunned the 9 for years due to it's lack of power. (Let's not start the caliber debate again. This is just my opinion...you know what they say about opions ;)) With our first session out the front door into the wood pile I discovered that my shots were more accurate than they had been for some time. Now the PT-92 is a good gun and a great value but it is not a tack driver and no more accurate than my Smiths. The fact is, difficult as it may be to admit, I was shooting better because I was not being beat up by the gun. Am I going to switch to a 9? No. But I have started down loading my .44 and .41 rounds.
To test this theory have someone else load a revolver for you using one or two empty cases placed at random in the cylinder. You might be surprised to discover you jerk the gun when you come to the empties.

I was typing as Parabellum was posting. It looks like we were of the same thought albeit I was a tad more long winded about it. ;)

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Gunslinger

I was promised a Shortycicle and I want a Shortycicle!

[This message has been edited by Gunslinger (edited August 30, 2000).]
 
This is just a hypothesis but I would think that the ratio of the diameter of the bullet to the length of the barrel would have something to do with it. Given the same clearance shouldn't the smaller bullet have a longer barrel in relationship? Some expert help me out- is such a thing a defined parameter? I would think all other things being equal that a .22 would be more accurate out of a certain length barrel than a .45 (no flame intended). Somebody help the novice (me) out.

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Those who use arms well cultivate the Way and keep the rules.Thus they can govern in such a way as to prevail over the corrupt- Sun Tzu, The Art of War
 
Now I find that I shoot bigger bored handguns better than smaller ones. Not including .22's. I can shoot my Beretta 96 far better than my 92. I can also shoot .44mag. better than .357mag. Maybe it's just my guns.

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Fud,

Your interesting question caused me to consider this issue as an aerodynamics analysis, something with which I have lots experience (at least for tactical aircraft). I suggest bullet shaping and flight dynamics may be a substantial part of the answer -- not just human factors such as "flinching". In general, smooth and slender objects tend to exhibit better stability and control than draggy and squat ones. Technically, this is due to their aspect ratio, fineness ratio, and drag count.

For example, I have personally noted that I tend to shoot .45 ACP, .38 Special, and .357 magnum rounds better than the .40 S&W. The "stoutest" of these certainly is the .357 mag, yet I consistently shoot it better than the .40 S&W.

When I carefully look at the bullets -- I have done no real measurement or testing, although I'd love to see some wind tunnel results -- the aerodynamic characteristics (e.g., fineness ratio, low drag smoothing, aspect ratio) seem to favor the 38, 45, and 357 mag. Doesn't the .40 S&W projectile (regardless of weight) seem less aerodynamic than the .38 Special, for example? Also, it's important to remember that the speed of these rounds may change -- within fractions of a second -- from subsonic, to transonic, to supersonic, and back down to subsonic as they move down range. This "velocity band" migration is always difficult to achieve without losing some stability.

Therefore, I presume human factors are part of the dynamic, but aero characteristics are also a key element.

Best regards.


[This message has been edited by RWK (edited August 30, 2000).]
 
One thing I forgot to mention...

The .40 doesn't have a stellar reputation for accuracy...

Part of it could also be your gun, FUD. Even though they're identical, not all guns have the same inherent accuracy potential.

Gunslinger -- We agree on something?

NOOOOOOOOOOOOOOOOOOOOOOOOOOOOO!!!! :D

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Beware the man with the S&W .357 Mag.
Chances are he knows how to use it.
 
What RWK said.

Born out by assorted writings on external ballistics.

Field proven by results turned in with stock handguns in metallic silhouette matches. Knocking over the 45lb ram at two hundred yards with a handgun requires hitting a sweet spot about five inches in diameter (high shoulder hit). .357 has the accuracy but lacks the power to be consistant even with jacketed bullets. .44 mag has both the accuracy and down range power.

With a decent bullet shape, any accuracy problem with the larger bores is usualy shooter problem, not calibre problem.

Sam...my favorite 9mm is the 9X32, 180gr supersonic.
 
Hmmm...I can't tell much difference recoil-wise between the 9, .40 & .38.

The above calibers feel "light" and sometimes "sharp" with hotter loads while the .45 just feels a bit heavier but not as sharp.

Ofcourse all this depends on the weight and grip of the gun.

But, hey I'm a weirdo who ENJOYS recoil...so what do I know?

:D

BTW, I carry a 640 S&W with 110 grain JHP Magnums. I also practice with this load. Now that's a bit of recoil!
 
i don't know if this is true but the .40 in general is a less accurate round than the 9mm. also i believe the 5906 and 4006 only have 4" barrels and the 9mm goes faster than the .40 so it has a flatter trajectory and will hit more at the point of aim farther away.

another thing to consider is that even though most (not all) of the recoil happens after the bullet exits the barrel there is still more recoil. so you may anticipate the more recoil in the .40 and then move the gun down or off target right before it goes off.
 
FUD.....I guess it could be that the 9mm is more on target than the .40. I shoot a 9mm Browning High Power and a .40 High power and would have to say that with the right load for each their accuracy is about the same, with a slight edge to the 9mm. I think that a pre ignition push is more likely. Your brain is trying to react to the recoil of the .40 before it is actually hapening. Just take the .40 to the range by it self and keep shooting . I shoot every week and usually it's .40 or .45ACP. After several years of every Sunday I have lost most of my perception of recoil. I'm not talking .44 mag here just 9mm, .40 and .45ACP. Shoot Safe.....CO

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"I won't be wronged, I won't be insulted, and I won't be laid a hand on. I don't do these things to other people and I require the same from them." From the movie, " The Shootist"
 
There are 2 different aspects to accuracy. One is the intrinsic accuracy of the gun and its load. This can be determined by machine rest firing. It may well be that your 9mm is quite a bit more intrinsically accurate than your 40 happens to be. Then there is the aspect of what the shooter can do with a given gun and load, and that is rarely anywhere near what the machine rest proves is possible, especially from standing and without any sort of a brace. You did not say that you used the sitting braced firing position, proven best accurate load,nor did you test a proven match accurate 19ll and match ammo, which is certainly a larger caliber, but the midrange SWC ammo is very mild in nature. Mostly, it is the greater blast and bounce of the more powerful rounds that make it more difficult for the shooter to maintain his concentration on sight picture and trigger control, but for the sub 10 ft ranges of 80+% of civilian defensive shootings, it is certainly irrelevant, while the extra power may mean everything.
 
There are two reasons why the 40 has a bad reputation for accuracy. First is the fact that most of the barrels I have seen are .402-.403, this doesn't work well with a .400-.401 bullet. Have you slugged your barrel yet?

The second problem with the 40 is the 1 in 16 twist barrel, this doesn't work well with the accepted standard of 180gr@980fps, you either need a lighter, shorter, faster bullet or a faster twist to increase the spin of the bullet, 1 in 14 would be great for the 40S&W. The 1 in 16 works with the 10mm due to the increased velocity of the round which increases the RPM to the point where it is stable.

Why the manufacturers don't fix either or both of these problems is beyond me. With the right load, my Beretta 96 Elite is the most accurate gun I have.

For some in-depth reading on external ballistics, check out: http://www.fulton-armory.com/fly/index.htm

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NRA, GOA
"If you choose not to decide, you still have made a choice"-Neil Peart
Vote in November.
 
Problems with inaccurate fire with larger calibers are often traced to anticipation-flinch. The shooter simply tends to jerk the trigger in anticipation of recoil and blast.

No one like to admit to this problem, so it might help to have an experienced shooter looking over your shoulder.

If that's the problem, it will probably show up by reading your groups. For right-handed shooters, the groups will tend to cluster loosely below and to the left of aim-point.

The only way I know of to cure the problem is very slow and deliberate slow-fire practice, concentrating on squeeeezing that trigger - just as if you were shooting a rifle at 300 yards.

I've seen this problem creep into my own shooting when I haven't shot my compact .45 for some time.

Once cured, regular practice is the best way to prevent re-occurence.
 
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