Measuring and Drilling Gas Ports

[jtallen83]

What do I need for tools and bits to drill out an undersized gas port? Any specifics I should look for on the bits or will any decent quality bits work? Once drilled is there a deburring procedure or can I just send a few rounds through to smooth it out?

[sketch]

This is a good ? Ive thought about the burr ? As well after many threads here. 

As for bits i wouldnt go cheep and defitnetly a steel specific grade! Slow and steady?

[Matt.Cross]

What do I need for tools and bits to drill out an undersized gas port? Any specifics I should look for on the bits or will any decent quality bits work? Once drilled is there a deburring procedure or can I just send a few rounds through to smooth it out?

My gas port measures .093" which translates to a #43 drill (number drills, not fractional).

Edited September 14, 2015 by Matt.Cross
Massive error

[jtallen83]

My gas port measures .093" wwhich translates to a #8 drill (number drills, not fractional). A #8 measures .0925" but any drill will "walk" and drill slightly oversize by a few thou.

What type barrel is that port size on? I have a 16 inch rifle gas that I think needs more umph.

[Matt.Cross]

Mid-weight profile, 18.5" rifle length gas system.

[MikedaddyH]

Slow the f... Down ! 

First length of barrel 

Second length of gas system

Third rifle caliber

 

I have a chart that I made up just need to find it !

Matt that drill bit number make NO sense.

#41 ~.094" for rifle gas and 24" barrel?

[MikedaddyH]

Look at the thread 

I have a AR-10T that short cycles ......

I gave it CPR and it went to the top. Has some sizes on the second page Dane Armory post.

[MikedaddyH]

What do I need for tools and bits to drill out an undersized gas port? Any specifics I should look for on the bits or will any decent quality bits work? Once drilled is there a deburring procedure or can I just send a few rounds through to smooth it out?

Run a couple of cloth swabs through the tube to make sure metal is out. Should be GTG shoot.

[jtallen83]

Looks like a 7/64 (.1094) gets me a match for the Fulton Armory rifle length gas system on a 16 incher(.1095). I've got that already. I think I'll set up in a drill press so I can control the depth for sure! Hope this works, she felt smooth the way it was but then that was without much buffer or carrier movement:)

[Matt.Cross]

Matt that drill bit number make NO sense.

#41 ~.094" for rifle gas and 24" barrel?

You're right on, #43 is what I should've said. I'll fix my post quicklike. I am stupid tired ATM, shouldn't be posting anyways... LOL

Edited September 14, 2015 by Matt.Cross

[Robocop1051]

My 17", rifle length gas, .308 has a .099" hole. You max out at .125"

[shepp]

Maybe look for wood dowel to fit inside so just I case it does slam thru u don't damage the rifling???

Edited September 14, 2015 by shepp
I suck at grammar

[jtallen83]

Had one laying around in case of a squib load. Now it looks like X-Caliber may want the whole upper to diagnose the issue...not sure what to do now!

[Malig8r]

JT, if it were me I would send them the upper. I know it would be cool to figure this out yourself but look at it this way. If they screw it they have to fix it on their dime. If you screw it up you eat the cost. 

Don't get me wrong,  I'm all for almost any excuse to buy new tools but in this case I'd let them diagnose the issue & then have em tell ya what was wrong so if something similar ever happens you can then move forward with rectifying it.

Either way, I am sure we would all like the know the path you choose and the results.

[Rsquared]

Either way, I am sure we would all like the know the path you choose and the results.

Nahh! I don't care.

 

 

 

 

 

 

Just kidding JT