Gap 10 under gassed and not loading next round?

[giannid]

My buddy came over today with a rifle he picked up used and was told it was a gen 1. We had a bunch of different 308 ammo we shot through it and it would usually eject the brass, but not load the next round from the magazine. Has a surefire socom brake so I figured someone adjusted the gas block down for a suppressor. After looking at the gas block, I see no way to adjust it. Included is a picture of the gas block. Anyone know what it is and if it's adjustable? I figure it has to be turned down or the rifle would run properly.

 

[hlee]

Is that little bright circle on the left side of the gas block a set screw or a roll pin? That block looks like a vanilla non-adjustable low pro gas block- available from a dozen vendors for a few bucks. But, if that circle is a set screw, that could be your adjustment. That said, an adjustable gas block is not an absolute requirement for proper function (suppressed or not), but it does add margin for tuning a rifle.

Load a single round in the mag and see if the rifle will lock back on empty.

Check gas block alignment.

Use plenty of lube.

What buffer is being used?

Any info from the previous owner on round count and functionality?

 

[bigjake83]

Load a single round in the mag and see if the rifle will lock back on empty.

Check gas block alignment.

Use plenty of lube.

What buffer is being used?

This^^^

Then report back, you may have to actually weigh the buffer.

The gas block isn't misaligned and is a non-adjustable so I'd bet it's running a heavy buffer that is designed for suppressed operations.

 

[msgriff]

That does not look like an adjustable gas block. Other gas tuning methods to look for would include a RCA tunable gas key and a BRT EZTune gas tube. Over-speed is often confused for under-gassed, check your buffer weight. And make sure the buffer length and spring is correct for the receiver extension

 

[giannid]

Is that little bright circle on the left side of the gas block a set screw or a roll pin? That block looks like a vanilla non-adjustable low pro gas block- available from a dozen vendors for a few bucks. But, if that circle is a set screw, that could be your adjustment. That said, an adjustable gas block is not an absolute requirement for proper function (suppressed or not), but it does add margin for tuning a rifle.

Load a single round in the mag and see if the rifle will lock back on empty.

Check gas block alignment.

Use plenty of lube.

What buffer is being used?

Any info from the previous owner on round count and functionality?

That little screw is the role pin. It's definitely not locking back with a single round. Haven't dug into it much because we ran out of time. I'm not sure what buffer is being used but does have a fixed rifle stock with the rifle tube. There was no info from the previous owner and it was purchased from a pawn shop. The rifle is pretty clean and doesn't look like it's been used much if at all. It was shooting some real good groups at 200.

Is it possible that the manufacturer put a heavy buffer in for suppressed use? I'm just wondering if we call them with the serial number, if they can give us some info.

 

[346ci]

Its possible it left GAP with one, who did what to it when the pawn shop got it is the real question. The buffer may be stamped with an "H1" or some number after the H to show what weight it is.

 

[Mike_in_FL]

GAP10s. I wonder if car forums have people buying Corvettes and Ferraris saying I had a bunch of old gas laying around and it doesn't run for shit on it. Federal GMM 175 is it's 93 octane. Your mileage with Tula may vary.

 

[mewillis]

LOL I shit you not, I nearly wrecked my car turning my head to make sure I wasn't seeing things. A guy with a Ferrari Enzo was gassing it up at a Circle K in Naples Fl. Lots of money but limited capacity to think.........