Please explain INACCURACY on a pistol

B

Burger

New member
All of these slow motion videos shows the bullets leaving the barrel so fast that the slide movement is captured in a couple of frames (if that) while the bullet is already gone. Doesn't this mean the barrel has even less movement by the time the bullets exits the barrel?

After seeing all those slow motion videos of bullets, it seems unfair to blame a firearm for problems with accuracy because there is almost no movement of the barrel to effect the flight/trajectory of a bullet. As long as the barrel is in the exact spot as the previous shot, how is the aim of the barrel effected.

I understand that the flight of the bullet can/will/may be effected by load which effect velosity and then there's the wind as another variable, but is inaccuracy mostly a human constant?
 
Many believe that the more you spend on a firearm the more accurate it is.

Here is the formula:

A = ($+X)(N)/30

A= Accuracy (percentage of chance that bullet will hit target)
$= Cost of weapon
X= Number of letters in brand of firearm
N= Number of magazines supplied with weapon

:D Do the math, it is kind of funny. I made the formula true for high dollar pistols.
 
Well, the more reliable a pistol, such as a glock or XD, the less likely the barrel will return to the exact same place each time. Also, rifling and bullet sizing have effects on a barrel as well. However, most "inaccurate" pistols actually shoot fine. Some people have unrealistic expectations of accuracy and others simply don't want to admit that they're flinching.
 
Also, just he fit/weight of the gun for each individual shooter. In 45, I shoot an XD Tactical with a 5" barrel, and a Hi-point 45 with a 4.5" barrel. They are about the same size overall and the Hi-point is much heavier. I can't seem to shoot the XD worth a damn, and I shoot a lot more accurately with the Hi-point. Go figure...
 
As long as the barrel is in the exact spot as the previous shot, how is the aim of the barrel effected.
Click to expand...

In semi-auto's, you dont actually aim the barrel. You aim the slide which happens to hold the barrel. The problem is that the barrel doesnt always "lockup" to the slide consistently in the same posistion from shot to shot. You may have perfectly aligned the sights (which are affixed to the slide), but the barrel may be slightly misaligned causing poor accuracy.

For example, the standard issue barrel bushing in a 1911 can be rather "loose" in terms of barrel fit to allow for reliable cycling. An accurized 1911 with an especially snug barrel bushing will help keep the barrel consistently in the same position from shot to shot. The problem is that as the barrel heats up from rapid or sustained firing, it can expand enough inside the bushing to lock up tighter than snot...and effect cycling.

Barrel lockup is less of an issue for pistols that have fixed barrels, like the PPK,... but there is still the issue of sights being affixed to the slide instead of the barrel. Revolvers tend to be more accurate because the sights are truly affixed to the barrel.
 
Even with revolvers you have the variation of the timing of the chambers and chamber sizes that change the position each shot hits the forcing cone subtly and can also affect the bullet flight.

You are right though. Most "inaccuracy" problems are shooter, rather than firearm related.
 
Inaccuracy can be increased when a firer does not adhere the norms of proper firing but that is another issue.Some handguns are realy inaccurate due to their material, design and mechanism.Even clones of few guns could not give the desired results like the original ones because metallergy, parts and material effected the accuracy factor.
As you stated that the bullet leaves the barrel so fast that accuracy may hardly be effected by movement of barrel.But the reality is little different as this slightest movement of the barrelchanges the path of bullet where it was originally aimed.
Before a good handgun is brought to market it undergoes hundreds of changes aftest test over tests to bring it highly accurate there fore such handguns have high price.In such tests some time weights is shifted from one point to other or some time rigidity or rlsticity of springs are increased or decreased or sometimes designs are changed by increasing or decreasing the length width or thickness etc....
I hope I tried to justfied my viewpoint :)
 
Barrel movement DOES affect the final point of impact. This is why handguns always have the barrel pointed downwards at rest relative to the level of the sights. (This is masked by the slide on many automatics; it's more obvious on revolvers, particularly snubbies.) Since the barrel centerline of a handgun is almost always well above the centerline of the grip, the barrel pivots up under recoil, so the sight plane is typically set to point the barrel downwards to compensate for this. This also explains why, at typical handgun ranges, a heavier bullet hits higher on the target than a lighter bullet loaded to a similar power level. Heavier bullet = more recoil and (typically) longer time spent within the barrel = more barrel movement before the bullet exits.

Another factor is torque (twisting force). The bullet engaging the rifling creates a torque on the gun in the opposite direction of the rifling; remember Newton's Third Law of Motion. This is most obvious if you shoot a powerful handgun using a relatively limp one-handed hold; you'll notice that the gun doesn't kick straight up, it moves off to one side.

In addition to the uncertainty in barrel lockup mentioned by Skadoosh (good post!), remember that guns and bullets are manufactured by humans and therefore aren't ever dimensionally flawless. Barrels are never perfectly straight, muzzles are never cut exactly perpendicular to the bore axis, rifling is never cut to a perfectly uniform depth, bullets are never perfectly concentric, and so on. Consequently, bullets don't leave the bore going perfectly straight- they wobble, resulting in a slightly helical path as they leave the bore. The bullet's spin subsequently straightens this out for the most part, but the variables in what happens before the bullet stabilizes have an effect in accuracy. A more precisely manufactured (and more expensive!) firearm can minimize these effects but never eliminate them completely.
 
In my opinion, I'd have to answer your question with yes. Inaccuracy in a firearm is mostly due to external factors and not the gun itself. With the stringent design and testing procedures in today's manufacturing the guns themselves are extremely accurate and I doubt I could find one that is less accurate than I am. Maybe that's because I need more practice.
That said, engineering tolerances do somewhat affect the accuracy and reliability but we're talking about fractions of a millimeter here.

Here's a link to a quick discussion from an engineering perspective on how tolerances and clearances affect a firearm. Some of you might find it interesting.

http://i.imgur.com/rowkK.jpg
 
Let's not forget that unless the shooter is using match grade parts all around, including the ammunition, the differences are going to be hard to detect.

Standard "cheap" practice ammo may contain micro variances. They will almost always meet tolerances, but if you want to try something out, weigh your ammo before firing it. Use an accurate scale that can convert to grains. Then, if you feel up to it, empty the powder onto the scale and then measure the bullet by caliper and weigh that too.

Are all 9mm 115gr projectiles exactly 115gr?

Are all .45 ACP 230gr projectiles exactly 230gr?
 
Mechanical accuracy is accomplished by taking measures to insure that the barrel, and to a lesser degree the slide, are locked in the same precise position at the moment of firing, from shot to shot. Hence the fitting of bushing to barrel, bushing to slide, barrel hood to slide, upper and lower lugs and ultimately, the slide to frame in a match-built pistol.

Practical accuracy involves measures taken by the individual shooter to insure that the sights are perfectly aligned at the moment the bullet departs the barrel. If your pistol is mechanically accurate and you accomplish this shot after shot, you are rewarded with small groups precisely where they belong. Precisely zeroed sights, a good trigger and a grip that fits the shooter are all means to this end.
 
Quote:
With the stringent design and testing procedures in today's manufacturing the guns themselves are extremely accurate and I doubt I could find one that is less accurate than I am.
I found one that is very inaccurate(although it's a revolver, not a pistol). I'm still waiting to hear back from the manufacturer. Here's a link to my thread.

http://thefiringline.com/forums/showthread.php?t=482663
Click to expand...

Wow, that is bad. Hopefully you find out what's wrong with it soon, sounds like you may have gotten a defective gun.
 
Burger:

I agree with carguychris 100 percent. Whether you can see it or not the pistol or revolver is moving while the bullet moves down the bore.

Semper Fi.

Gunnery sergeant
Clifford L. Hughes
USMC Retired
 
Mechanical accuracy is accomplished by taking measures to insure that the barrel, and to a lesser degree the slide, are locked in the same precise position at the moment of firing,
Click to expand...

It matters just as much as when the bullet leaves the barrel.

The slide in every auto locked breech recoil operated pistol has started to move before the bullet exits the muzzle.

The ability to maintain the same mechanical relationship from ignition to bullet exit repeatedly is the mechanical accuracy.

The ability to exert the same forces on the gun as it starts to recoil every time is the shooters job.

Your nerves are not fast enough to react whole the bullet is moving down the barrel, so things like muscle tension must be the same and held the same during the barrel travel.

It is being able to repeat everything over and over that gets the best accuracy.
 
Accuracy

Old Bear is correct in my opinion. "Yes" it's human error (barring a defect in the pistol). For me the trigger is pretty much the whole story, the "ALL" if shooting irons.
 
Trigger

Skadosh, of course you are right. I should have worded that post differently. In most cases it's shooter, not the pistol. And there are many things that go into making a marksman. For me, it's much easier to shoot a pistol very accurately, if it has a good trigger. An example would be Glock pistols. My experience is they are really quite accurate. Yet it's difficult for some to shoot them to the level of accuracy they are capable of. Mainly because of the trigger.
 
No offense, but if you think a Glock has a good trigger, you have never shot anything with a good trigger. Well, I guess they would be considered good. But there are some fantastic triggers out there. They are great guns though.
 
You must log in or register to reply here.
Back
Top