AK-Builder AK74 5.45x39 barrel

**def90** · November 21, 2012, 16:20

Seeing that it seems to be impossible to find any information on US made AK barrels I thought I would post this here. I will update at the end of the project as well as list any issues noted to me via the builder.

For my 2 Bulgarian kits I decided on using the barrels that AK-Builder sells. From what I can tell online depending on what you read these are either Green Mountain blanks or Montana Rifleman blanks and the external contour is finished by Curtis at AK-Builder.

From AK-Builder website:
"These barrels are made from 4140 rifle blanks with a .214" bore and 1-8 twist. Each barrel is stamped USA 5.45 for 922r compliance.

The gas port is drilled, handguard retainer is cut and extractor clearance is cut on the chamber end."

From my 2 samples the gas port was not drilled, it is started but does not go all the way through to the bore which is probably a good thing as some gas blocks are 90 degree and some are 45 degree. I did not get a chrome lined barrel, they were back ordered and I did not want to wait for them and I am not sold that a barrel needs to be chrome lined anyway. The machine work looks nice and clean.

Crown looks good but I am contemplating having a target crown put on while they are blank just for the hell of it, what could it hurt? Thoughts on this from the peanut gallery?

Barrel diameter measurements with calipers are:

Trunion = 22mm, Rear sight block = 17.52mm, Gas Block = 15.05, and front sight = 14.55.

I plan on parking these this weekend and then sending them out with my parts to have them populated and headspaced.

cbr954fz1 · November 21, 2012, 22:08

thought about doing acouple myself but i'm waiting to see how yours come out...

please keep us updated..cbr

**def90** · December 08, 2012, 11:58

Had 11 degree target crowns pt on the barrels this week.

littlematt · December 11, 2012, 14:26

very cool. i can't wait to hear how they shoot

**MajHenryWest** · December 14, 2012, 01:22

What does it mean to have a barrel "populated"?

ALL FAL · December 14, 2012, 02:03

Barreling the trunion and setting headspace, basic set up of an new barrel for an AK.
I hope this is right.

I have heard of Copulated barrels, Hehe.

With some tuned ammo that AK should really perform.

**def90** · December 14, 2012, 23:10

Quote:

Originally Posted by MajHenryWest

What does it mean to have a barrel "populated"?

Taking all of the components such as front sight block, gas block and rear sight block and installing them onto a virgin barrel.

November 21, 2012, 16:20	#1
def90 Old Fart Silver Contributor FALaholic #: 50609 Join Date: Nov 2009 Location: The Peoples' Republic of Boulder, Colorado Posts: 8,835	AK-Builder AK74 5.45x39 barrel Seeing that it seems to be impossible to find any information on US made AK barrels I thought I would post this here. I will update at the end of the project as well as list any issues noted to me via the builder. For my 2 Bulgarian kits I decided on using the barrels that AK-Builder sells. From what I can tell online depending on what you read these are either Green Mountain blanks or Montana Rifleman blanks and the external contour is finished by Curtis at AK-Builder. From AK-Builder website: "These barrels are made from 4140 rifle blanks with a .214" bore and 1-8 twist. Each barrel is stamped USA 5.45 for 922r compliance. The gas port is drilled, handguard retainer is cut and extractor clearance is cut on the chamber end." From my 2 samples the gas port was not drilled, it is started but does not go all the way through to the bore which is probably a good thing as some gas blocks are 90 degree and some are 45 degree. I did not get a chrome lined barrel, they were back ordered and I did not want to wait for them and I am not sold that a barrel needs to be chrome lined anyway. The machine work looks nice and clean. Crown looks good but I am contemplating having a target crown put on while they are blank just for the hell of it, what could it hurt? Thoughts on this from the peanut gallery? Barrel diameter measurements with calipers are: Trunion = 22mm, Rear sight block = 17.52mm, Gas Block = 15.05, and front sight = 14.55. I plan on parking these this weekend and then sending them out with my parts to have them populated and headspaced. __________________ There is no theory of evolution, just a list of creatures Chuck Norris allows to live. Public libraries cannot let the public decide what is allowed in the library, or it would be brimming with pornography and gun magazines.

December 08, 2012, 11:58	#3
def90 Old Fart Silver Contributor FALaholic #: 50609 Join Date: Nov 2009 Location: The Peoples' Republic of Boulder, Colorado Posts: 8,835	Had 11 degree target crowns pt on the barrels this week. __________________ There is no theory of evolution, just a list of creatures Chuck Norris allows to live. Public libraries cannot let the public decide what is allowed in the library, or it would be brimming with pornography and gun magazines.

December 14, 2012, 01:22	#5
MajHenryWest Senior Member Gold Contributor FALaholic #: 11906 Join Date: Sep 2003 Posts: 656	Question What does it mean to have a barrel "populated"? __________________ ****************************** "Steel is Strong because it Knows the Hammer and White Heat." - Johnny Cash, These Things Shall Pass

December 14, 2012, 02:03	#6
ALL FAL Registered Contributor FALaholic #: 24447 Join Date: Jan 2007 Location: Oregon Posts: 2,167	Barreling the trunion and setting headspace, basic set up of an new barrel for an AK. I hope this is right. I have heard of Copulated barrels, Hehe. With some tuned ammo that AK should really perform. __________________ The Future is ALWAYS Open!! An ARMED society is a POLITE society.

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November 21, 2012, 22:08	#2
cbr954fz1 Registered FALaholic #: 35401 Join Date: Apr 2008 Location: florida Posts: 1,079	thought about doing acouple myself but i'm waiting to see how yours come out... please keep us updated..cbr

December 11, 2012, 14:26	#4
littlematt Registered FALaholic #: 64395 Join Date: Oct 2011 Location: louisiana Posts: 272	very cool. i can't wait to hear how they shoot