Barrel length

J E Custom

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Joined
Jul 29, 2004
Messages
10,723
Location
Texas
The way to measure is to make sure the weapon is empty of all ammo, close the action/bolt.
insert a cleaning rod in the muzzle until it makes contact with the bolt face and make a mark on the rod at the crown.

Remove the cleaning rod and measure the rod from end to mark.

That Is barrel length.

J E CUSTOM
 

RustyRick

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Jul 5, 2013
Messages
264
Location
North Western Alberta
Done :)

I find that a little subjective as cases from different calibers vary SO much that the ratio of bolts face to crown (which include case length) would not be consistent.

But rifling to crown would always indicate a TRUE barrel length.

When we are in an industry that measures things by .001 I'd think we be exact on this one.

But oh hum I lost my bet. GRR
 

J E Custom

Well-Known Member
Joined
Jul 29, 2004
Messages
10,723
Location
Texas
Done :)

I find that a little subjective as cases from different calibers vary SO much that the ratio of bolts face to crown (which include case length) would not be consistent.

But rifling to crown would always indicate a TRUE barrel length.

When we are in an industry that measures things by .001 I'd think we be exact on this one.

But oh hum I lost my bet. GRR


You are correct about the effective barrel length being the point that the bullet touches the rifling
and that would be where the barrel starts to have an effect on the bullet.

A short mag would have slightly more rifle bore than a standard magnum even though the barrel was the same length measured to the bolt face.

The measurement to the bolt face started hundreds of years ago when all weapons were muzzle
loaders and you measured all the way to the breach block or back of the chamber. ram rods were marked with this dimension to prevent loading with no powder or an over charge.

This method of measuring barrel length has stuck and when cartridge guns came along it did not change.

If you think about it, on modern weapons the barrel tenon is flush with, or recessed to clear the bolt or action. so the tenon is part of the barrel and the measurement is still very close from muzzle to bolt face.

It is also the official way to measure rifles, pistols, shotguns for any barrel length compliance length
if required.

J E CUSTOM
 
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