Ar15 Gas port hole

S

shepherm

Guest
Ok I am building a 6x45 and plan on using the rifle gas tube but how do I know where to drill the hole. I have the barrel on the lathe and turning it down but need to know how far the gas block and port is from the chamber end.
Thanks
Mark
 
Gas port location

The standard location is 12.415" from where the extension touches the barrel or 13.040" if you use 0.625" for the tenon length. You may have to experiment with the gas port diameter, as 0.0935 may not be large enough with your small case in a larger diameter bore than the 223/5.56.

The shoulder for the gas block is determined by the gas block hole location. Measure the hole location precisely - each one is different, even from the same manufacturer.

Have fun,

HPC
 
Ok great thanks for the help. I got the barrel turned down to 1in and threaded for the extension. Now I am going to finish turning it to the .937 for the gas block and then order the reamer.
 
Centering in the groove

For the standard EPVAT barrels I drill and tap every day, I useally use a shopmade jig that slides into the bore and lets me use a indicator to time the location of the port. For the non standard calibers, twists and location, I use a Hawkeye borescope with a right angle lens to find the groove at the port location. I did a 7.62mm 1-12" barrel last month that had 18 test ports in it, all in the same groove. Try a couple of holes in a scrap barrel to learn the method that will work for you.
 
You must log in or register to reply here.
Back
Top