Bullet size question

nanewt02 · March 12, 2013, 11:29 PM

im looking on Pacnors custom barrel page and they offer a barrel i want in 20mm, however, it has (.825) next to it. 20mm is .79 something. is there any barrel maker out there who makes a true 20mm? i need something around the .79 area .

still confused why pacnor says 20mm, but states .825

Jimro · March 13, 2013, 07:36 AM

PacNor lists the groove to groove dimension. Call them directly to see what the land to land dimension is.

Some quick math in my head says that .825 minus .790 is .035, which would give a rifling depth of .0175". But you'll need a barrel with the groove to groove diameter matched to the projectile you want to use.

Jimro

March 12, 2013, 11:29 PM	#1
nanewt02 Senior Member Join Date: February 25, 2013 Posts: 249	Bullet size question im looking on Pacnors custom barrel page and they offer a barrel i want in 20mm, however, it has (.825) next to it. 20mm is .79 something. is there any barrel maker out there who makes a true 20mm? i need something around the .79 area . still confused why pacnor says 20mm, but states .825

March 13, 2013, 07:36 AM	#2
Jimro Senior Member Join Date: October 18, 2006 Posts: 7,097	PacNor lists the groove to groove dimension. Call them directly to see what the land to land dimension is. Some quick math in my head says that .825 minus .790 is .035, which would give a rifling depth of .0175". But you'll need a barrel with the groove to groove diameter matched to the projectile you want to use. Jimro __________________ Machine guns are awesome until you have to carry one.