[Griff]

I finally got a chance to take the family to the range today, and on the list of things to sort was the Mini-14. Got the thing sighted back in pretty quick, accurate as always...

Had a bunch of mild/sedate loads ready to go to get the gas block set. Set to full open, the Mini was, of course, throwing brass far enough to get a warning from NORAD about air space violations. I began turning the adjustment screw in half turn at a time, and not really noticing any reduction. The short story, I ended up with the screw turned in all the way, to max possible, and brass was still flying 12-15 feet. it never really fully closes, and even at max, the rifle always fully cycled and chambered.

At that point, I just enjoyed the rest of the range time, as there was nothing further I could do there. When I got home, I figured something must be wrong, so I took the block off, and checked all fitment, alignments, etc. Nada.. everything was exactly where it should have been, screwed in where it should, to the distance allowed by design specs, Ruger factory bushing was good.

My expectation was to turn in the screw until such point that it no longer fully cycled, then back it out a bit from there, and continue testing. Maybe that expectation was wrong? Not sure on my next course of action, maybe give ASI a call.

Anyone else try the Gen5 blocks yet?


G

 

[RIBob]

I have yet to install my adj. gas block. When I ordered it, I also bought the gas plug/oriface that the mfr suggested be used with it. What was the internal diameter of the gas plug/oriface installed in the rifle along with the new adj. gas block?

I'd give ASI a call. Can't see anything obviously wrong about your adjustment plan. I would have begun with gas adj fully closed, and opened it up until rifle functioned normally. Then maybe 1/4-1/2 turn further open, just to be sure. But that's just how I'm familiar with adjusting FAL gas systems.

 

[wv.citybilly]

My expectation was to turn in the screw until such point that it no longer fully cycled, then back it out a bit from there, and continue testing.

I have the HBSII from ASI and that's exactly what I did.

 

[Griff]

Thanks Guys I spoke with ASI this Morning, super friendly folks, VERY helpful on the phone. Took some measurements on the pin that goes into the gas tube, OD on mine is about ~.085, the ID of the port on the gas tube itself is ~.093. They checked a few screw/pins they had, and they come in ~.090. So, pin wise, mine is ~.005 smaller OD. Certainly more than enough to change the pressure characteristics. They are sending me out a new screw/pin with a larger OD. We'll see how it goes 🔧🔨🔫

Gas port on the barrel is ~.067, Ruger factory bushing is ~.102, lol.

G

 

[RIBob]

Thanks Guys I spoke with ASI this Morning, super friendly folks, VERY helpful on the phone. Took some measurements on the pin that goes into the gas tube, OD on mine is about ~.085, the ID of the port on the gas tube itself is ~.093. They checked a few screw/pins they had, and they come in ~.090. So, pin wise, mine is ~.005 smaller OD. Certainly more than enough to change the pressure characteristics. They are sending me out a new screw/pin with a larger OD. We'll see how it goes 🔧🔨🔫

Gas port on the barrel is ~.067, Ruger factory bushing is ~.102, lol.

G

Interesting info, and thanks for posting it. I'm having some stainless steel screws made to replicate OEM carbon steel adjustible gas block screws, so OEM dimensions for the gas block/screws are most pertinent.

 

[Griff]

No worries

The screw/pin I am referring to is what ASI calls the GPAS, "Gas Pressure Adjustment Screw". The pin part of that screw that goes into the gas pipe is where the diameter issue is. It allows way too much blow-by at max depth, rendering it effectively useless.

 

[RIBob]

Understood. The shank of my Adjustment screw is "turned-down", almost eliminating the base of the threads on my adjustment screw.

I have not measured the diameter of the "turned-down" section of my Adjustment screw. Will measure it and report.

 

[RIBob]

No worries

The screw/pin I am referring to is what ASI calls the GPAS, "Gas Pressure Adjustment Screw". The pin part of that screw that goes into the gas pipe is where the diameter issue is. It allows way too much blow-by at max depth, rendering it effectively useless.

Can you measure the Outside Diameter of your gas adjustment screw with a caliper or other pecise measuring instrument? We'll need reliable measurements in the .001 inch level of precision.

 

[Griff]

Can you measure the Outside Diameter of your gas adjustment screw with a caliper or other pecise measuring instrument?

For which part... Head? Threads? Pin?

The pin (turned-down) section is as mentioned, mine was ~.085, ASI indicated it should be around ~.090.

Or did you mean another section of that screw?

 

[RIBob]

You got it right; just the turned-down portion. Thanks.

 

[Griff]

The new ASI GPAS arrived the other day, got it all put back together again. New pin is coming in at ~.0905. Now, if I can just get to the range this week, and see how it behaves...

G