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Wild Bunch 1911


WiggleyDY

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From the hood on the barrel chamber to muzzle of barrel - the hood and rest of chamber is part of the barrel on any semi-auto pistol.    So if you have the barrel out, you measure the longest length, from hood face to muzzle.   If you have barrel assembled in the gun, find the slide's breech face (it's inside the recess for the hood), measure from there to the muzzle.   You can even drop a pencil down barrel (with slide closed) and mark pencil at the muzzle, and measure that length.  Same either way.   Because FFL defines barrel length as "bolt face to muzzle."

 

Most 1911s are 5" barrels.  If it is a military surplus gun, or Colt Government model, or Springfield MilSpec model, it's a 5". 

 

Commander lengths are 4.25"   Some concealment type guns made since 1980s have even shorter barrels.

 

Long Slides are 6" (or longer). 

 

And ALL the makers list the barrel length in the specifications for the gun.

 

Good luck, GJ

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Rear of the chamber to end of barrel.

 

If there were a round seated in the firearm; the primer end of the cartridge case is the rear of the chamber.

 

Unlike a revolver where the barrel is separated from the chamber; all firearms with integral chamber and barrel include the chamber length in the measurement.

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18 minutes ago, Doc Coles SASS 1188 said:

Unload the gun, put a dowel down the barrel and mark it at the muzzle.  Pull it out and measure from the mark to the end of the dowel and that is the barrel length.

:D

Remember do all the above with the slide closed.

Don't want the man to end up thinking he has a 6 3/4" barrel.

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Just sitting here blank faced drinking bourbon, reading how much people write and how many people reply with so many ways to do something so simple. 

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Fill it up with water, then measure the volume of the water the barrel holds.  Then use the formula for finding the volume in a cylinder. 

 

V = (pi X r^2) X L.  Where V is the volume in cubic inches and L is the length of your barrel in inches. 

 

Since it's a .45 we can fill in the piRsquared part with .159.  So :

V = .159 X L

 

Rearrange it to solve for L and you get

L = V / .159

 

Just divide the volume you get by .159 and VIOLA, you got your barrel length.  It doesn't get any simpler than that. 

 

Yes, I took Last Chance's post as a challenge. 

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I prefer to use a known quantity of inert gas such as 1 mole Argon to fill the barrel. Then I measure the temperature and the pressure of the gas, and plug it in to the ideal gas law to get the volume.

 

V = (nRT)/P where V = Volume, n = Moles, P = pressure, T = Temperature, and R = 8.31432×10^3 N⋅m⋅kmol−1⋅K−1

 

Once I have the volume, I just use Ramblin Gamblers methods to solve for length. I prefer the Gas method because its less messy, when you're done you just uncork it and let it waft some where.

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1 hour ago, Ramblin Gambler said:

Fill it up with water, then measure the volume of the water the barrel holds.  Then use the formula for finding the volume in a cylinder. 

 

V = (pi X r^2) X L.  Where V is the volume in cubic inches and L is the length of your barrel in inches. 

 

Since it's a .45 we can fill in the piRsquared part with .159.  So :

V = .159 X L

 

Rearrange it to solve for L and you get

L = V / .159

 

Just divide the volume you get by .159 and VIOLA, you got your barrel length.  It doesn't get any simpler than that. 

  

Yes, I took Last Chance's post as a challenge. 

 

wait,  your method requires measuring the length of the barrel.  which is what we are trying to determine by using the volume so wouldn't it be:

 

fill the barrel with water, measure the volume of the water, calculate the inside diameter @ .450 inches and then extrapolate the barrel length

 

so

 

V= (diameter/2)^2 X pi X length X 7.48 gallons/cubic foot. Substituting terms V = (0.450/2) squared X 3.1416 X 12 = 1.908522 gallons per foot.

 

so 1.908522/12in = 0.15904 gallons per inch

 

so by measuring the amount of water from the barrel at 0.7952 gallons, and dividing it by 0.15904 gallons per inch, you have a 5" barrel

 

pretty simple

 

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26 minutes ago, Boomstick Bruce said:

 

wait,  your method requires measuring the length of the barrel.  which is what we are trying to determine by using the volume so wouldn't it be:

 

fill the barrel with water, measure the volume of the water, calculate the inside diameter @ .450 inches and then extrapolate the barrel length

 

so

 

V= (diameter/2)^2 X pi X length X 7.48 gallons/cubic foot. Substituting terms V = (0.450/2) squared X 3.1416 X 12 = 1.908522 gallons per foot.

 

so 1.908522/12in = 0.15904 gallons per inch

 

so by measuring the amount of water from the barrel at 0.7952 gallons, and dividing it by 0.15904 gallons per inch, you have a 5" barrel

 

pretty simple

 

 

To be fair, he actually did end up with L = V/.159 so he would be solving for L since he measured volume instead :D

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Shoot a round through a chronograph, then measure the distance from the breach of your gun and then the muzzle to the chronograph. Now divide that speed by that distance in inches and you will know what your barrel length is.

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