Gas port question

[Bluedog225]

 

I am working on understanding the exact specs of my PA-10 so I can ask more intelligent questions about a rebuild.  Generally leaning towards new gas tube (mine is short), appropriate buffer, and spring. 

I’ve got the gas block off and the gas port looks odd to me.  It looks like it was filled and drilled.  Is this normal?  The hole is off-center to the filled area.

Additionally, my 3/32 bit will not fit.  And my selection of smaller bits is limited.  What is a better tool for determining the gas port size with the tolerances needed to get accurate info?  This is the best pic I could get a close range.

Thanks

 

Edited October 6, 2020 by Bluedog225

[DNP]

This has been fired right?  The gas port is smaller than the hole in the gas block and that’s the carbon and BS buildup between the two. 

[Bluedog225]

That’s it.  It came off.  Thanks.  Would have been an odd repair.

[DNP]

Numbered drill bits are really the easiest way to measure.  Some of these guys have that part down to a science and will recommend the right sized port. If 3/32 didn’t fit, I’m guessing they’ll suggest upsizing that port. 

[Bluedog225]

Ok.  I can pick up some bits.  Thanks

[sagebrush]

@Bluedog225ace hardware has number type drill bits, irwin brand i believe

Edited October 7, 2020 by sagebrush

[98Z5V]

9 hours ago, Bluedog225 said:

 

I am working on understanding the exact specs of my PA-10 so I can ask more intelligent questions about a rebuild.  Generally leaning towards new gas tube (mine is short), appropriate buffer, and spring. 

I’ve got the gas block off and the gas port looks odd to me.  It looks like it was filled and drilled.  Is this normal?  The hole is off-center to the filled area.

Additionally, my 3/32 bit will not fit.  And my selection of smaller bits is limited.  What is a better tool for determining the gas port size with the tolerances needed to get accurate info?  This is the best pic I could get a close range.

Thanks

 

If that's a PSA 18" midlength-gas barrel, then taht gas port diameter right there is 0.070".  That ring around it will measure 0.125", because that the max gas diameter of the ID of a gas tube - and that's what they drill the diameter to in a gas block - just like DNP stated.

For an 18" midlength-gas .308 Win barrel, with a 0.750 gas block journal size (gas block diameter), your gas port diameter in the barrel needs to be something between 0.080"~0.085".