Is a barrel's length measured from the beginning of the tennon threads to the muzzle, or is it measured from the end of the chamber where the bullet tip rests?
How to measure barrel length?
- Thread starter BigDon
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Doom2
Well-Known Member
Put a dowel down the barrel against the bolt face. Mark the dowel at the muzzle crown or the end of a fixed non removable muzzle device.
^^^
This- neither of those mentioned in the OP is correct.
BATFE- measured from the boltface.
Some mistakenly also think it's measuring from the receiver/barrel shoulder junction.
Usually no need for precision here, and you certainly don't want to "cut it close" if you're after minimum legal length.
This- neither of those mentioned in the OP is correct.
BATFE- measured from the boltface.
Some mistakenly also think it's measuring from the receiver/barrel shoulder junction.
Usually no need for precision here, and you certainly don't want to "cut it close" if you're after minimum legal length.
MagnumManiac
Well-Known Member
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- Feb 25, 2008
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When looking at a complete rifle, where the vent hole is in the action, this is adjacent to the end of the chamber, this is where you measure from. If it's the barrel only, it's the entire length from one end to the other.
Hope this as clear as mud.
Cheers.
Hope this as clear as mud.
Cheers.
J E Custom
Well-Known Member
There is a legal way to measure barrel length and it is from the bolt face to the muzzle. There is also an effective barrel length measurement that Is from the beginning of the lands to the muzzle. (this measurement is not used because most people cant find that point and because It varies based on the cartridge it's self and is the point that the barrel takes control of the bullet and pressure.
It is however a good way to understand the velocity gain in actual barrel length. A good example of the difference in this way of measuring effective barrel length would be the difference in a 7 mm short magnum and a standard 7 mm rem magnum with the same barrel length from the bolt face to the muzzle. The difference is 0.409 in actual effective length. Not much, but a 1/2 inch can increase the velocity with all things being equal. with even shorter cartridges, the effective barrel length can be more The 7 mm BR would be more than 1.500 inches longer than the 7 rem mag in the same length.
So the right/universal way to measure the barrel length that best fits all cartridges is the bolt/ breach face to the muzzle.
J E CUSTOM
It is however a good way to understand the velocity gain in actual barrel length. A good example of the difference in this way of measuring effective barrel length would be the difference in a 7 mm short magnum and a standard 7 mm rem magnum with the same barrel length from the bolt face to the muzzle. The difference is 0.409 in actual effective length. Not much, but a 1/2 inch can increase the velocity with all things being equal. with even shorter cartridges, the effective barrel length can be more The 7 mm BR would be more than 1.500 inches longer than the 7 rem mag in the same length.
So the right/universal way to measure the barrel length that best fits all cartridges is the bolt/ breach face to the muzzle.
J E CUSTOM
LoneTraveler
Well-Known Member
JE Custom covered the many way a barrel can be measured to figure bullet travel and ballistics.
To be Legal by Federal Law.
If you are measuring a barrel to check if it is legal by BATFE regulations.
When I was in the BATF class at the State Police Academy the instructor's demonstration was, Remove any removable Chokes or Flash Suppressors. Close the action, Insert Dowel Rod from muzzle to Breech Face, Mark Dowel Rod even with muzzle, Measure Dowel Rod from Breech Face End to muzzle mark on Dowel Rod Shotgun, 18 inch barrel, 26 inches overall. Rifle, Barrel Rifled and 16 inches in length, 26 inches overall
Years ago someone imported a European Alpine Military Rifle, That had a sleeve added by welding or silver solder to the end of its 40 Centimeter barrel, So it could be imported and sold in the USA.
To be Legal by Federal Law.
If you are measuring a barrel to check if it is legal by BATFE regulations.
When I was in the BATF class at the State Police Academy the instructor's demonstration was, Remove any removable Chokes or Flash Suppressors. Close the action, Insert Dowel Rod from muzzle to Breech Face, Mark Dowel Rod even with muzzle, Measure Dowel Rod from Breech Face End to muzzle mark on Dowel Rod Shotgun, 18 inch barrel, 26 inches overall. Rifle, Barrel Rifled and 16 inches in length, 26 inches overall
Years ago someone imported a European Alpine Military Rifle, That had a sleeve added by welding or silver solder to the end of its 40 Centimeter barrel, So it could be imported and sold in the USA.
nmbarta
Well-Known Member
JE's explanation of this is part of the reason why some people think shorter cartridges are more efficient. I'm not saying they are or aren't. But when comparing a 7mm wsm to a 7mm rem mag, and comparing velocity to powder charge in relation to barrel length, this is usually overlooked. The wsm appears to have a slight advantage in efficiency, (this argument could be made for several cartridges") but if you really want to compare efficiency, this has to be taken into consideration.
Varmint Hunter
Well-Known Member
Powder burn starts at the primer. Both the 7WSM and the 7Mag would effectively be burning powder at the same point. I'd be surprised if a shorter cartridge benefits from just being shorter. Based on the short/fat cartridge craze I assume that keeping more powder closer to the primer results in more efficient combustion.
But who knows?
But who knows?
J E Custom
Well-Known Member
Efficiency is a different subject altogether, and has nothing to do with how to measure barrel length.
There are many considerations when choosing barrel length and other considerations when wanting to use effective barrel length to get the most of a cartridge and rifle combo.
A short cartridge and short action can have a longer barrel and still be the same overall length with the added effective barrel length. Cartridge design can/will have the most effect on efficiency. Velocity is effected by barrel length if everything else is the same.
I probably didn't explain it very well and should just have stated the correct way to measure a barrel only. Through the bore from the breach face/bolt to the muzzle of the bore without attachments.
J E CUSTOM
There are many considerations when choosing barrel length and other considerations when wanting to use effective barrel length to get the most of a cartridge and rifle combo.
A short cartridge and short action can have a longer barrel and still be the same overall length with the added effective barrel length. Cartridge design can/will have the most effect on efficiency. Velocity is effected by barrel length if everything else is the same.
I probably didn't explain it very well and should just have stated the correct way to measure a barrel only. Through the bore from the breach face/bolt to the muzzle of the bore without attachments.
J E CUSTOM
