Gas Port Data

[Muzap]

Yes, pin gauges can and should be calibrated. They can be sent out to a metrology lab or the user can verify diameter with a calibrated mic, caliper or go/nogo gauge. The metrology lab can also ensure the pin gauges are round and parallel[/QUOTE]

That's what I meant when I said "confirm it with a calibrated micrometer." You're right that this is a form of calibration. Where I work, and most places where pin gauges are used professionally, they have a "no calibration required" label rather than a calibration done/required sticker, as they can't be adjusted, only verified. I apologize for the murky terminology; I'm just used to thinking of them as non-calibrated tooling.

[jpmuscle]

Best set of quality yet reasonable priced pin gauges? Anddd go

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[Iraqgunz]

Yes, especially if it's not being suppressed. People need to be more concerned about function, and not a little overgassing. That function should also include less than ideal conditions. A 16" mid seems to work just fine across the board at .076.

All the way up to .080? Interesting. I always thought the common .078 was sufficient and anything beyond that was too much. When talking about a 16mid, what would you say is the ideal size?

[SkipD]

Yes, pin gauges can and should be calibrated. They can be sent out to a metrology lab or the user can verify diameter with a calibrated mic, caliper or go/nogo gauge. The metrology lab can also ensure the pin gauges are round and parallel.

That's what I meant when I said "confirm it with a calibrated micrometer." You're right that this is a form of calibration. Where I work, and most places where pin gauges are used professionally, they have a "no calibration required" label rather than a calibration done/required sticker, as they can't be adjusted, only verified. I apologize for the murky terminology; I'm just used to thinking of them as non-calibrated tooling.

I worked for 39 years in the industrial process control systems business. Much of my work in the latter years was controlling calibration process documents, calibration documents, etc., as well as doing calibration of temperature, pressure, flow, and physical measurement systems among others. One thing that most folks don't realize is the "calibration" is very simply the act of comparing an unknown quantity to a known (usually certified) quantity and reporting the results. Adjustment of the unknown is a separate step and another calibration must be done after the last adjustment.

Depending on what the pin gauges would be used for, periodic calibration may be required even though they cannot be adjusted if they fail the calibration tolerance. They would have to be replaced and the new pieces would have to be calibrated.

[Muzap]

I worked for 39 years in the industrial process control systems business. Much of my work in the latter years was controlling calibration process documents, calibration documents, etc., as well as doing calibration of temperature, pressure, flow, and physical measurement systems among others. One thing that most folks don't realize is the "calibration" is very simply the act of comparing an unknown quantity to a known (usually certified) quantity and reporting the results. Adjustment of the unknown is a separate step and another calibration must be done after the last adjustment.

Depending on what the pin gauges would be used for, periodic calibration may be required even though they cannot be adjusted if they fail the calibration tolerance. They would have to be replaced and the new pieces would have to be calibrated.

Okay, so:
Use pin gauges to find port diameter.
Verify pin gauge with calibrated micrometer.
Done.
That's the point I was making. Do this, and you'll get an accurate measurement.

[Defaultmp3]

Bump for exposure.

[Serious Account]

Bump

And does anyone here know the port size of the new Colt midlength rifle?

[Bob Sacamano]

Thanks for sharing this info. Should a standard spec shared by retailers. Nothing worse than having to buy something to see if it will meet your specs.

Measured with a minus set of pin gauges. Port sizes reported are for the largest pin that fit into the port.

BCM 20" Rifle Gas Gov Profile Chrome Lined: 0.093"

Daniel Defense 14.5 Carbine Gas CHF Chrome Lined: 0.066"

WOA 10.5 HBAR Carbine Gas SS: 0.078"

Noveske 10.5 Carbine Switchblock S Port: 0.063"

[vicious_cb]

Thanks for sharing this info. Should a standard spec shared by retailers. Nothing worse than having to buy something to see if it will meet your specs.

Measured with a minus set of pin gauges. Port sizes reported are for the largest pin that fit into the port.

BCM 20" Rifle Gas Gov Profile Chrome Lined: 0.093"

Daniel Defense 14.5 Carbine Gas CHF Chrome Lined: 0.066"

WOA 10.5 HBAR Carbine Gas SS: 0.078"

Noveske 10.5 Carbine Switchblock S Port: 0.063"

Very close to the reported 0.067" I got from 2 mfg sources.

[tom12.7]

For a few reasons, I would lean towards that selected as if Colt sized porting for that emphasized offering for similar barrels/ chambers/ throat/ etc..
Using a larger port than required leads to many negatives with this system, adding stresses and strains that the majority do not need to be there to begin with and some timing issues that can be avoided.
Why sacrifice reliability, durability, timing, etc. overall to achieve more reliability for a select minority of the few that are almost excluded totally from any possible serious use?
Why cater to them, the ammunition should cater to the platform, not the other way around.
A change in porting of .003" may not sound like much and it isn't for the most part, but the wrong direction for the majority is still the wrong direction overall.