Stag10 build short stroking issues resloved !! I needed a Armalite gas tube ??

Thanks for the thread! My Stag 10 was only cycling hotter ammo. It wouldn't grab a round from the mag or lock back on empty mag with lighter ammo like 7.62x51 and most 150 grain. I tried everything like others, checked alignment of gas block, etc. It was definitely under gassed. Pic below is how short my gas tube was, please excuse dirtiness I shot hundreds of rounds trying to figure out how to fix it and haven't cleaned yet. lol



xhdIhKf.jpg
 
cbabes said:
Yeah tube should be half way into the cut out. The OP has a 15.5" which goes a little past half which seems to work. True North Arms has a proper .308 rifle gas tube which is 15.375. The one originally in my pic above is 15.125.
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There's a discussion of this on the TNA website... truenortharms.com/gas-tubes-for-ar-10-dpms-308.html

It's still hard to figure out which gas tube goes with which barrel however. I ordered a barrel from them recently and specifically requested they send along the proper length gas tube for the Anderson barrel. When it arrived....wrong tube [so maybe they can't be sure either]. Fortunately my gunsmith had a spare tube that worked.
 
Tengoo said:
There's a discussion of this on the TNA website... truenortharms.com/gas-tubes-for-ar-10-dpms-308.html

It's still hard to figure out which gas tube goes with which barrel however. I ordered a barrel from them recently and specifically requested they send along the proper length gas tube for the Anderson barrel. When it arrived....wrong tube [so maybe they can't be sure either]. Fortunately my gunsmith had a spare tube that worked.
Click to expand...

The TNA “Sanderson” barrel, Faxon 20” big gunner, and I think the Criterion need the longer gas tube.
 
Tengoo said:
There's a discussion of this on the TNA website... truenortharms.com/gas-tubes-for-ar-10-dpms-308.html

It's still hard to figure out which gas tube goes with which barrel however. I ordered a barrel from them recently and specifically requested they send along the proper length gas tube for the Anderson barrel. When it arrived....wrong tube [so maybe they can't be sure either]. Fortunately my gunsmith had a spare tube that worked.
Click to expand...

Yeah I made sure to measure how far the difference from 15.375 to 15.125 would go into the cutout and it will be exactly half way in. Regardless, it will no doubt increase the gas pressure over what was working with the hotter ammo so I feel pretty confident it will work. Ordered it xpresspost yesterday.
 
My gas tube from TNA came in. It was perfect. Couldn't resist trying it out right away. Now my Stag is purring like a kitten. Shoots all ammo including 7.62 x 51. Happy Camper.


Perfect length...
Yj9Vf86.jpg
 
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Big JD-From the hills said:
So im seeing a trend then. Faxon and fulton are most definately needing the longer gas tube. Fingers crossed my ibi is going to work with ar 15 rifle length tubes. Someone in the know is going to have to make a sticky on this once we collect more data. If people that are building/and have parts infront of them could measure the gas port hole to the flange that contacts the upper of the barrel extention we can quickly figgure out what going on.
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Stupid question... Does anyone know what barrel manufacturer is for a stock Stag Arms STAG 10 M-LOK Rifle 18.75'' in .308 ?
I am having short stroking issues as well and have staked the original gas block as well and its still not functioning :-(
Will a longer gas tube fit for this ?

Can't understand how a brand new $2k rifle doesn't function??

Also in some M&P 10 reviews many have said that the gas port hole in the barrel is undersized and that it needs to be reamed out... any thoughts?
 
CanadianSummers said:
Stupid question... Does anyone know what barrel manufacturer is for a stock Stag Arms STAG 10 M-LOK Rifle 18.75'' in .308 ?
I am having short stroking issues as well and have staked the original gas block as well and its still not functioning :-(
Will a longer gas tube fit for this ?

Can't understand how a brand new $2k rifle doesn't function??

Also in some M&P 10 reviews many have said that the gas port hole in the barrel is undersized and that it needs to be reamed out... any thoughts?
Click to expand...

It’s most likely a Ballistic Advantage. Send it back for warranty.
 
It wasn’t loose but I have a suspicion that it was off in alignment from factory. I removed the gas block and when I put the jig on to dimple the barrel I could see that the original set screws were off from centre.

I looked at the gas tube last night... sorry no pics :-( and it seems to be the proper length.
My next guess is that the gas port is undersized on the barrel. I didn’t have callipers but did slide a 5/64” drill bit to measure. After doing some research on the Ar10 websites it sounds like the port should be .0960


DPMS LR-308 Style Rifle
18" rifle 0.308 0.0960
18" car 0.308 0.0635
16" mid 0.308 0.078
16" mid 0.308 0.081
16" car 0.308 0.07
16" car 0.308 0.073
16" car 0.308 0.076
20" rifle 0.308 0.0935
20" rifle 0.308 0.096
 
CanadianSummers said:
It wasn’t loose but I have a suspicion that it was off in alignment from factory. I removed the gas block and when I put the jig on to dimple the barrel I could see that the original set screws were off from centre.

I looked at the gas tube last night... sorry no pics :-( and it seems to be the proper length.
My next guess is that the gas port is undersized on the barrel. I didn’t have callipers but did slide a 5/64” drill bit to measure. After doing some research on the Ar10 websites it sounds like the port should be .0960


DPMS LR-308 Style Rifle
18" rifle 0.308 0.0960
18" car 0.308 0.0635
16" mid 0.308 0.078
16" mid 0.308 0.081
16" car 0.308 0.07
16" car 0.308 0.073
16" car 0.308 0.076
20" rifle 0.308 0.0935
20" rifle 0.308 0.096
Click to expand...

I used a gauge pin to align my gas block jig on my MRA barrel, 18.5" rifle length and it was a .0960 gas port hole in the barrel

5/64 would only be .078125
 
Yeah its crazy that it would come like that from the factory.
Thanks for confirming that your's is at .0960! regardless of what you read on the net its nice to get confirmation from someone who's actually measured.
Now I just need to find a 2.4mm drill bit LOL
 
CanadianSummers said:
Yeah its crazy that it would come like that from the factory.
Thanks for confirming that your's is at .0960! regardless of what you read on the net its nice to get confirmation from someone who's actually measured.
Now I just need to find a 2.4mm drill bit LOL
Click to expand...

Id stick with the imperial size of .0960

I have a few machine shop supply type places down the street from my shop, they carry drill bits in every size imaginable, and they are better quality then most general purpose dill bits from hardware store type places. KBC tools has a minimum of $20 purchase but I usually just find a bottle of loctite or something else to buy to bring it over the minimum

Canadian tire and other big box stores will not have them
 
Just an update,

I drilled out the gas port on the barrel to .0960 and the rifle functions flawlessly... I was shooting Federal 7.62 x 51 and no issues whatsoever.
 
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