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View Full Version : How to enlarge a .308 gas port hole without calling NASA



timshufflin
07-05-2017, 12:26 PM
I have seen some of the most ridiculous posts lately regarding the gas port of the .308. First off let me say that the gas port of your Garand should be as small as it can be while having the rifle cycle reliably. When I receive .308 Criterion barrels from Ammo Garand, my Criterion supplier, they come at .086" for gas port. When I assemble someones rifle I may or may not have to enlarge this hole depending on the wear of their firearm. If someone sends me a receiver to mount a new .308 barrel on then I install the barrel as is because I cannot possibly know the condition of the parts that they will be using. Even how you position the gas cylinder can make a difference, yes it's true. You want as little gas as needed because it will treat you to less recoil and your receiver heel to less fatigue, those are good things.

Here's a video on how I enlarge a gas port for the Garand. I don't use a wooden dowel in the barrel, I do stuff some cardboard in them, I don't use a vise, I don't wear a lab coat, I don't care if the drill is square, I don't care about anything except for making the most simple hole you could make. Please, ignore those who try to make this complicated, it is NOT. You don't have to be an engineer to do this, I can do it.


https://youtu.be/i-zm5pyWPSc

Water Monkey
07-05-2017, 01:00 PM
Thank you sir!

canes7
07-05-2017, 02:54 PM
Tim - I know a hole is a hole.... but no lube?

I've only done this 2x. Both times I free handed it, like you. The only differences were that I had put a ring of electrical tape around the bit to use as somewhat of a stop and to know how far I drilled. Second difference is I used some lube. I agree though, to take the time to set it up in a machine is over kill. The gas does not care what angle the hole is. Unless you have no mechanical skill at all you can't get the angle of the drill too far off.

timshufflin
07-05-2017, 03:02 PM
Tim - I know a hole is a hole.... but no lube?

I've only done this 2x. Both times I free handed it, like you. The only differences were that I had put a ring of electrical tape around the bit to use as somewhat of a stop and to know how far I drilled. Second difference is I used some lube. I agree though, to take the time to set it up in a machine is over kill. The gas does not care what angle the hole is. Unless you have no mechanical skill at all you can't get the angle of the drill too far off.

Yep, treat it like a common democrat and go no lube. These things blow through in seconds, I don't know that much heat is even generated because the barrels are so soft. I would think the barrel wall thickness at the gas port is only about .146" so I'm not lubing for a cherry that thin.

timshufflin
07-05-2017, 03:07 PM
One more thing, a common problem when not using lube for drilling is your drill bit wears out. I use 3/32 drill bits on all my Mini-G's, I make a lot of Mini-G's. I drill them all dry and this is only my 3rd 3/32 drill bit after all these years. I don't think much wear is occurring.

Punch The Clown
07-06-2017, 12:29 AM
Amazing! Genius!

Orlando
07-06-2017, 07:41 PM
No lube? You barbarian

jason60chev
07-08-2017, 08:17 PM
Hope that barrel end wasn't cut off of my E model build!!!!! LOL!

Water Monkey
07-30-2017, 11:26 AM
Thank you Shuff! Got her up and running as she should after I drilled her open!!!