7.62x39 build questions
I'm building a 7.62x39mm AR for a customer. He provided me with a barrel blank and gas block, and wants a 20" barrel with a rifle length gas system. I already bought the reamers and headspace gauges.
Will this even run with a rifle length gas system? What's my options for a 7.62x39mm rifle?
Runs well. Use m4 style feed ramps. Also check out the variants section.
Topic Moved
Will the 7.62 round have enough pressure to cycle well with a 20" bbl and rifle gas system? What gas port size should I use?
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By "customer" you mean someone is paying you, and you are asking questions like this on the internet? Shouldn't you know this already?
As for a gasport diameter start I would start with a .082", If it needs to get resized to a larger diameter you will have plenty of room to do so.
JMHO, you will have to test fire the barrel once it has been threaded, ported and the M4 barrel extension torqued and pinned...The X39 round
can be a little picky with the rifle length gas system in the AR-15 platform...
Good Luck.
http://illirianengineeringc.ipage.com/Originally Posted By BB:
By "customer" you mean someone is paying you, and you are asking questions like this on the internet? Shouldn't you know this already?
I build bolt guns and ARs, I'm turning down a barrel blank. I've made AR barrels from blanks before, but only in .223 and .308.
I'm just making sure that it will run with a rifle length gas system.
Posted Via AR15.Com MobileOriginally Posted By Dr69er:
As for a gasport diameter start I would start with a .082", If it needs to get resized to a larger diameter you will have plenty of room to do so.
JMHO, you will have to test fire the barrel once it has been threaded, ported and the M4 barrel extension torqued and pinned...The X39 round
can be a little picky with the rifle length gas system in the AR-15 platform...
Good Luck.
http://illirianengineeringc.ipage.com/
This is why I'm asking. Would a midlength be better?
Posted Via AR15.Com MobileI had a Colt Blue Label 20" in 762x39 and had no problems. It did not shoot any more accurate than my Model 1 which is very good, so I sold it.((((((((((Edit)))))))) The Model 1 is a 16"
I'll sell you a model 1 sales in 20" if you are interested, then you don't have to worry about it.Georgetown Texas
Originally Posted By TexasRifleman:
Originally Posted By Dr69er:
As for a gasport diameter start I would start with a .082", If it needs to get resized to a larger diameter you will have plenty of room to do so.
JMHO, you will have to test fire the barrel once it has been threaded, ported and the M4 barrel extension torqued and pinned...The X39 round
can be a little picky with the rifle length gas system in the AR-15 platform...
Good Luck.
http://illirianengineeringc.ipage.com/
This is why I'm asking. Would a midlength be better?
Posted Via AR15.Com Mobile
Not necessarily, the 20" bbl. length was designed for a rifle length gas system...and when we are talking about the x39 cartridge in the
AR-15 a mid-length or a rifle gas system is preferred due to the cartridge case design/case taper of the x39mm round. Because of the
considerable case taper of the x39mm cartridge bolt thrust can become a Issue for the AR-15 action,..so in 16" to 18" bbl. length(s)
I would go with a mid-length gas system, with a 20" or longer bbl. length I would go with the rifle length gas system.
Hope it helps you...
http://illirianengineeringc.ipage.com/
