Superlative Arms adjustable gas block gas tube hole isn’t Milspec height?

[Leicafan1990]

I was chatting with one of my range buddies about a build I’m doing and I mentioned that I was probably going to use a Superlative Arms adjustable gas block.

“Dude, don’t. Those Superlative gas blocks have the gas tube hole higher than a milspec gas block which causes the gas tube to enter the upper receiver at a slight downward angle. That will cause the gas tube to rub a lot on the BCG gas key and wear out the gas tube and gas key super fast. The gas adjustment mechanism doesn’t allow them to place the gas tube hole at normal height so they shift it up slightly and hope people don’t notice.”

Is this true? If so, why doesn’t Superlative Arms make a gas tube with the proper bend for their gas block? I emailed Superlative Arms about this but received no response.

 

[roostercogburn98]

My SA AGB works fine. Gun has spent plenty of time hitting steel at 600

 

[lash]

I was chatting with one of my range buddies about a build I’m doing and I mentioned that I was probably going to use a Superlative Arms adjustable gas block.

“Dude, don’t. Those Superlative gas blocks have the gas tube hole higher than a milspec gas block which causes the gas tube to enter the upper receiver at a slight downward angle. That will cause the gas tube to rub a lot on the BCG gas key and wear out the gas tube and gas key super fast. The gas adjustment mechanism doesn’t allow them to place the gas tube hole at normal height so they shift it up slightly and hope people don’t notice.”

Is this true? If so, why doesn’t Superlative Arms make a gas tube with the proper bend for their gas block? I emailed Superlative Arms about this but received no response.

That sounds like complete made up BS to me. I’ve used a number of them and still do. Never wore out any of those parts.

I’m no AR expert by far, but it just smells like BS to me.

 

[msgriff]

This is true. The mil-spec gas tube offset is 0.156" (+/- 0.005"). For an AR-15 with a 0.750" gas journal, the actual offset required for a SA AGB is 0.063". Fortunately, adjusting the gas tube offset is incredibly easy, and is part of the building process particularly when using non mil-spec parts. As it happens, the 0.750" SA AGB when used on a large frame lines up perfectly using a mil-spec gas tube.

 

[Bigjake83]

That sounds like complete made up BS to me. I’ve used a number of them and still do. Never wore out any of those parts.

I’m no AR expert by far, but it just smells like BS to me.

It is actually true, that's why any knowledgeable Smith will recommend using a strait Gas Tube with the SA AGBs. Most people don't take the time to properly install and ture the gas tube placement anyways so it commonly goes on unnoticed. You can use a standard Gas tube with the SA AGBs but you have to know how to do proper alignment.

 

[Leicafan1990]

It is actually true, that's why any knowledgeable Smith will recommend using a strait Gas Tube with the SA AGBs. Most people don't take the time to properly install and ture the gas tube placement anyways so it commonly goes on unnoticed. You can use a standard Gas tube with the SA AGBs but you have to know how to do proper alignment.

Wouldn’t a straight tube result in the tube sitting too low and prevent it from being able to go into the clover leaf opening on the front of the receiver? I would think you would need tube with a bend height somewhere between a straight tube and a standard milspec tube.

 

[Leicafan1990]

This is true. The mil-spec gas tube offset is 0.156" (+/- 0.005"). For an AR-15 with a 0.750" gas journal, the actual offset required for a SA AGB is 0.063". Fortunately, adjusting the gas tube offset is incredibly easy, and is part of the building process particularly when using non mil-spec parts. As it happens, the 0.750" SA AGB when used on a large frame lines up perfectly using a mil-spec gas tube.

Interesting. That’s extremely useful info. What’s the best way to adjust the gas tube to fit properly?

 

[FredHammer]

I stopped reading about 1 sentence in to that clown bullshit. You either use a restriction gas block like an Aero P or a bleed off like an SA. Typically I save the SA bleed off for over gassed ports or suppressed option.

 

[Leicafan1990]

I stopped reading about 1 sentence in to that clown bullshit. You either use a restriction gas block like an Aero P or a bleed off like an SA. Typically I save the SA bleed off for over gassed ports or suppressed option.

I don’t think you understood the point of this thread. It’s been verified that this is a real issue by other members in this thread. You will need to adjust your gas tube because the SA gas block has a gas tube hole that sits higher than a standard milspec gas block.

 

[FredHammer]

I don’t think you understood the point of this thread. It’s been verified that this is a real issue by other members in this thread. You will need to adjust your gas tube because the SA gas block has a gas tube hole that sits higher than a standard milspec gas block.

I’ve never noticed an issue in about 15 SA builds. I believe this is where the Internet creates the problem.

 

[B y r o n]

Strange how their installation instructions only mention using the appropriate length gas tube and no mention of needing a straight one or having to bend a standard tube.

 

[Bigjake83]

Wouldn’t a straight tube result in the tube sitting too low and prevent it from being able to go into the clover leaf opening on the front of the receiver? I would think you would need tube with a bend height somewhere between a straight tube and a standard milspec tube.

Well that's where the gas block size itself comes into play, .875 and up is when you really need to run a strait. Call SA they will explain it.

 

[roostercogburn98]

It is actually true, that's why any knowledgeable Smith will recommend using a strait Gas Tube with the SA AGBs. Most people don't take the time to properly install and ture the gas tube placement anyways so it commonly goes on unnoticed. You can use a standard Gas tube with the SA AGBs but you have to know how to do proper alignment.

By “tuning” do you mean slightly bending the tube so it has minimal contact with the key?

 

[MikeMiller]

This is true. The mil-spec gas tube offset is 0.156" (+/- 0.005"). For an AR-15 with a 0.750" gas journal, the actual offset required for a SA AGB is 0.063". Fortunately, adjusting the gas tube offset is incredibly easy, and is part of the building process particularly when using non mil-spec parts. As it happens, the 0.750" SA AGB when used on a large frame lines up perfectly using a mil-spec gas tube.

This is the answer. Only added always adjust the gas tube for perfect alignment with carrier gas key

 

[Leicafan1990]

This is the answer. Only added always adjust the gas tube for perfect alignment with carrier gas key

What’s the best way to do this?

 

[MikeMiller]

Easy. Take bolt out of carrier. Slide bolt carrier until it goes over gas tube. If gas tube moves to go into gas key the tube needs to be bent so it does not bind going in. Use HD scrapper or wide flat head screw driver to bend it

This is how I was taught at AR Armorers School years ago

 

[kthomas]

@reubenski turned me onto this, in my thread where I planned on using a superlative arms AGB.

Check out Black River Tactical's tunable gas systems and pinned gas blocks. No personal experience (yet), but seems like a neat way to get a tuned gas system for your specific rifle.

 

[Bigjake83]

By “tuning” do you mean slightly bending the tube so it has minimal contact with the key?

I mean tune the entire gas system, some rifles require more then others. If I'm doing a high end custom rifle there's several steps I take.

First thing I do since it's the most tedious is bend the gas tube into position for perfect alignment.

Then I check the tolerances in the upper receiver for the Gas Tube Port, some are way too tight and require a little material removal. SP10's are notoriously tight.

Next I completely disassemble the gas system again fully disassembling the adjustable gas block and applying a coat of anti-seize to the internal parts, then the gas tube from the gas block polishing the gas tube nipple and carefully! reinstalling and sealing the gas tube in the gas block with Loctite 620 making sure to remove any excess.

And lastly install the gas system back on to the barrel sealing with 620 and blue loctite on the set screws or bolts.

 

[Leicafan1990]

@reubenski turned me onto this, in my thread where I planned on using a superlative arms AGB.

Check out Black River Tactical's tunable gas systems and pinned gas blocks. No personal experience (yet), but seems like a neat way to get a tuned gas system for your specific rifle.

They are great for dedicated suppressor builds but for people who switch between suppressed and unsuppressed, they aren’t the best fit. I split my time between a state where suppressors are banned and a state where they aren’t so I need to be able two change between gas settings. The SA block seems like the best option. I was also looking at the Riflespeed but my rail is too long and it covers even the longest dial they offer.

 

[1911hombre]

You can use a standard Gas tube with the SA AGBs but you have to know how to do proper alignment.

Like you have to know for any other build. FFS.

 

[Leicafan1990]

Like you have to know for any other build. FFS.

Honestly SA should just sell the gas block with the right gas tube. That would get rid of all the confusion. You shouldn’t have to tweak your gas tube to get it to fit right.

 

[Precision Underground]

Classic fudd-lore. Part of what he’s saying is true, the hole is a little higher. But since most gas tubes need to be bent anyway it really doesn’t matter. It’s like saying that you shouldn’t use a car part bc the hose connection is 1” to the left when you can just move the hose 1” to the left.

 

[MikeMiller]

Honestly SA should just sell the gas block with the right gas tube. That would get rid of all the confusion. You shouldn’t have to tweak your gas tube to get it to fit right.

Actually you should tweak it in most cases to get the best longevity and accuracy out of it. Should not touch sides of hole in receiver and should go into gas key without gas tube moving in any direction

 

[Leicafan1990]

I mean tune the entire gas system, some rifles require more then others. If I'm doing a high end custom rifle there's several steps I take.

First thing I do since it's the most tedious is bend the gas tube into position for perfect alignment.

Then I check the tolerances in the upper receiver for the Gas Tube Port, some are way too tight and require a little material removal. SP10's are notoriously tight.

Next I completely disassemble the gas system again fully disassembling the adjustable gas block and applying a coat of anti-seize to the internal parts, then the gas tube from the gas block polishing the gas tube nipple and carefully! reinstalling and sealing the gas tube in the gas block with Loctite 620 making sure to remove any excess.

And lastly install the gas system back on to the barrel sealing with 620 and blue loctite on the set screws or bolts.

Damn. That’s extremely thorough. Do you do this professionally or just for personal builds? I doubt that most gunsmiths go that far when building an AR upper but I wish they did.

Putting anti seize on the gas block components is a great idea. I’m going to try that. What’s your preferred compound?

Do you prefer a particular gas block model to do this on?

 

[TheOE800]

What’s the best way to do this?

Michiguns gas tube bender.

 

[MikeMiller]

Michiguns gas tube bender.

How about a link. Never too old to learn better way

 

[6.5SH]

How about a link. Never too old to learn better way

Michiguns Ltd. - AR-15 Tools and Accessories

Can still do it with a screwdriver etc. but a purpose made tool is better IMO.

 

[TheOE800]

How about a link. Never too old to learn better way

Never too old to learn to search the web, but looks like @6.5SH got you.

 

[Bigjake83]

Never too old to learn to search the web, but looks like @6.5SH got you.

What's the word on that barrel bro?

 

[MikeMiller]

Never too old to learn to search the web, but looks like @6.5SH got you.

Thank you. Far better way than I was taught 25 years ago

 

[TheOE800]

What's the word on that barrel bro?

Got it two or three weeks ago! Still waiting on some components to finalize, but the barrel looks great. Profile isn’t as silly as the M110 print with the .750” GB and forward.

 

[Bigjake83]

Got it two or three weeks ago! Still waiting on some components to finalize, but the barrel looks great. Profile isn’t as silly as the M110 print with the .750” GB and forward.

Yeah you'll be happy with it, every barrel Paul Ross at CLE turns for me is a laser.

This is the 24" CLE Bartlein on my JP LRI-20. First 28 rounds down the barrel cleaning every 5 rds.

 

[kentuckyMarksman]

I used a Superlative Arms gas block for a build using a .875" gas block journal. I carefully straightened my gas tube to work. No big deal, easy to do.