User Panel
Posted: 9/1/2024 1:39:10 PM EDT
Have a 9" Balistic Advantage 300BO barrel and a Superlative Arms adjustable gasblock coming my way.
This is only the second upper I have put together. With the SA gas block will I be able to run the GB against the shoulder on the barrel or should I offset it a little? Thank you! Shinji |
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[#1]
When it comes to mounting gas blocks onto a barrel, some barrels come pre-dimpled for the gas block rear screw, and some do not. In fact most of the barrels I come across do not. I have also seen some of the dimples that were not correctly aligned with the gas port, so it never hurts to check alignment.
My suggestion is to use an alignment / dimpling fixture, there are several on the market that are available. What you will find if using a gas block alignment/dimpling fixture, ours uses a cone shaped set screw that the tip of the screw goes into the gas port, is that most gas blocks don't butt against the shoulder of the barrel, that most will have a slight gas or space. CY6 Greg Sullivan "Sully" SLR15 Rifles DefensiveEdge.com (763) 712-0123 |
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[#2]
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[#3]
Originally Posted By Mav3rick: https://hbindustries.net/store/shop/ar15-gas-block-aligner-5-56mm/ View Quote I saw something along these lines but the person used a piece of dry spaghetti. |
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Shoot straight and tell the truth!
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[#4]
Originally Posted By Shinji_Ikari: With the SA gas block will I be able to run the GB against the shoulder on the barrel or should I offset it a little? Thank you! Shinji View Quote Attached File Attached File Attached File |
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Can't never could 'til try came along.
"All welchers should be removed from the EE".-Aimless R.I.P. to the EE |
[Last Edit: Slingblade2006]
[#5]
Bore scope. Good one cost about $55 on Amazon. Link
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Well, I was drunk the day my mom got out of prison....
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[#6]
If the gas block is secured with setscrews just turn the gas block 180 degrees, upside-down, and look through the first setscrew hole. The orifice of the gas block is drilled through the same hole as the first set screw of the gas block. If the gas port is centered in that setscrew hole when the gas block is pushed up against the journal there is no need to leave a gap.
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[Last Edit: s4s4u]
[#7]
Originally Posted By Slingblade2006: Bore scope. Good one cost about $55 on Amazon. Link View Quote Not sure what is that going to do for you. The hole in the barrel will be smaller than the orifice in the gas block and I'm not sure that bore scope will fit in a gas block |
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[#8]
Originally Posted By s4s4u: Not sure what is that going to do for you. The hole in the barrel will be smaller than the orifice in the gas block and I'm not sure that bore scope will fit in a gas block View Quote View All Quotes View All Quotes Originally Posted By s4s4u: Originally Posted By Slingblade2006: Bore scope. Good one cost about $55 on Amazon. Link Not sure what is that going to do for you. The hole in the barrel will be smaller than the orifice in the gas block and I'm not sure that bore scope will fit in a gas block I use a length of orange weed trimmer line to go into the gas block and used the bore scope to look up into the gas port. I can easily see the gas port hole with the orange line. |
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Well, I was drunk the day my mom got out of prison....
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[#9]
IIRC when I installed my SA adjustable the port on the GB is not huge. And I came off the shoulder the approx thickness of the handguard cap.
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Shoot straight and tell the truth!
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[#10]
Originally Posted By Slingblade2006: I use a length of orange weed trimmer line to go into the gas block and used the bore scope to look up into the gas port. I can easily see the gas port hole with the orange line. View Quote If it works for you, great. It really isn't difficult to align a gas block. I've never needed anything more than a piece of masking tape and a pencil. |
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[Last Edit: TGWLDR]
[#11]
Originally Posted By s4s4u: Not sure what is that going to do for you. The hole in the barrel will be smaller than the orifice in the gas block and I'm not sure that bore scope will fit in a gas block View Quote It'll show whether the GP/hole in gas block are in alignment or not. Attached File |
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Can't never could 'til try came along.
"All welchers should be removed from the EE".-Aimless R.I.P. to the EE |
[#12]
Originally Posted By TGWLDR: It'll show whether the GP/hole in gas block are in alignment or not. https://www.ar15.com/media/mediaFiles/416992/e7C6rrYh_jpg-3311417.JPG View Quote If the scope is looking through a 1/16" diameter hole, how is it going to see the edges of the 3/16" diameter orifice on the other side? There are much simpler ways to get the job done, that will be more accurate. |
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[#13]
Originally Posted By s4s4u: If the scope is looking through a 1/16" diameter hole, how is it going to see the edges of the 3/16" diameter orifice on the other side? There are much simpler ways to get the job done, that will be more accurate. View Quote View All Quotes View All Quotes Originally Posted By s4s4u: Originally Posted By TGWLDR: It'll show whether the GP/hole in gas block are in alignment or not. https://www.ar15.com/media/mediaFiles/416992/e7C6rrYh_jpg-3311417.JPG If the scope is looking through a 1/16" diameter hole, how is it going to see the edges of the 3/16" diameter orifice on the other side? There are much simpler ways to get the job done, that will be more accurate. As in the above pic.^^^^ There is definitely plenty of lee-way with most (not all GBs) but a cam can confirm/deny an alignment obstruction easily, as shown in the example. |
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Can't never could 'til try came along.
"All welchers should be removed from the EE".-Aimless R.I.P. to the EE |
[#14]
There are many ways to skin the cat. Alignment that I worry about is distance to make sure I've got the tube over the port, and functionality of the BCG with the gas key. I've seen armourers use a large flat screwdriver to tweak the alignment of the tube so it doesn't collide with the BCG.
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Shoot straight and tell the truth!
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[#15]
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Can't never could 'til try came along.
"All welchers should be removed from the EE".-Aimless R.I.P. to the EE |
[#16]
Originally Posted By sully: When it comes to mounting gas blocks onto a barrel, some barrels come pre-dimpled for the gas block rear screw, and some do not. In fact most of the barrels I come across do not. I have also seen some of the dimples that were not correctly aligned with the gas port, so it never hurts to check alignment. My suggestion is to use an alignment / dimpling fixture, there are several on the market that are available. What you will find if using a gas block alignment/dimpling fixture, ours uses a cone shaped set screw that the tip of the screw goes into the gas port, is that most gas blocks don't butt against the shoulder of the barrel, that most will have a slight gas or space. https://www.slr15rifles.com/v/vspfiles/photos/GasBlockAlignmentFixture-2T.jpghttps://www.slr15rifles.com/v/vspfiles/photos/GasBlockAlignmentFixture-4T.jpghttps://www.slr15rifles.com/v/vspfiles/photos/GasBlockAlignmentFixture-5T.jpg CY6 Greg Sullivan "Sully" SLR15 Rifles DefensiveEdge.com (763) 712-0123 View Quote I don't see that tool at that website. |
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[#17]
Originally Posted By TGWLDR: As in the above pic.^^^^ There is definitely plenty of lee-way with most (not all GBs) but a cam can confirm/deny an alignment obstruction easily, as shown in the example. View Quote Seems like a lot of something for nothing. It really ain't rocket surgery, although some make it seem so. For left and right indexing I just wrap a strip of masking tape around the journal and mark the location of the port on the tape. Place gas block on barrel and align the hole for the gas tube with the pencil mark and tighten down. Remove tape. Done! Flip the gas block 180 degrees prior to aligning the hole for the gas tube and look through the first set screw hole to to see if you need to leave a gap for the handguard cap. It is one of the simplest tasks in assembling an upper. |
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[Last Edit: TGWLDR]
[#18]
Originally Posted By s4s4u: Seems like a lot of something for nothing. It really ain't rocket surgery, although some make it seem so. For left and right indexing I just wrap a strip of masking tape around the journal and mark the location of the port on the tape. Place gas block on barrel and align the hole for the gas tube with the pencil mark and tighten down. Remove tape. Done! Flip the gas block 180 degrees prior to aligning the hole for the gas tube and look through the first set screw hole to to see if you need to leave a gap for the handguard cap. It is one of the simplest tasks in assembling an upper. View Quote Everybody has their pet method. |
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Can't never could 'til try came along.
"All welchers should be removed from the EE".-Aimless R.I.P. to the EE |
[#19]
I use dimpling jigs for .625 and .750 journal barrels.
5/32 masonry bit makes quick work of even nitrided barrels. The only gas block I've encountered that my jigs don't like is the KAC because the set screws are pretty close to each other. |
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Let's get after it.
For the glory of the empire, so say we all. I collect blank posts and use them |
[#20]
Originally Posted By M4ger: I use dimpling jigs for .625 and .750 journal barrels. 5/32 masonry bit makes quick work of even nitrided barrels. The only gas block I've encountered that my jigs don't like is the KAC because the set screws are pretty close to each other. View Quote And, honestly, you only need the one dimple. |
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[#21]
Originally Posted By DrJekell: I don't see that tool at that website. View Quote They are there now. Somehow they got unlisted when our webmaster was doing some updates. So they are back now. https://www.weaponsarmorer.com/product-p/gasblockalignmentfixture.htm CY6 Greg Sullivan "Sully" SLR15 Rifles DefensiveEdge.com (763) 712-0123 |
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[#22]
Originally Posted By Shinji_Ikari: Have a 9" Balistic Advantage 300BO barrel and a Superlative Arms adjustable gasblock coming my way. This is only the second upper I have put together. With the SA gas block will I be able to run the GB against the shoulder on the barrel or should I offset it a little? Thank you! Shinji View Quote Use a feeler gauge to set your gap to shoulder at 0.025" is the gas block the clamp-on type or set-screw type ? |
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[#23]
Originally Posted By TNRonin: I saw something along these lines but the person used a piece of dry spaghetti. View Quote View All Quotes View All Quotes Originally Posted By TNRonin: Originally Posted By Mav3rick: https://hbindustries.net/store/shop/ar15-gas-block-aligner-5-56mm/ I saw something along these lines but the person used a piece of dry spaghetti. I learned about the spaghetti trick here! Works great, no need for dimples |
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[#24]
Originally Posted By IndyGrendel63: I learned about the spaghetti trick here! Works great, no need for dimples View Quote While dimples (if located correctly) can simplify instalation, alignment isn't really the point of them. It's to prevent the block from being able to move after instalation. |
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[#25]
Originally Posted By Stowe: While dimples (if located correctly) can simplify instalation, alignment isn't really the point of them. It's to prevent the block from being able to move after instalation. View Quote View All Quotes View All Quotes Originally Posted By Stowe: Originally Posted By IndyGrendel63: I learned about the spaghetti trick here! Works great, no need for dimples While dimples (if located correctly) can simplify instalation, alignment isn't really the point of them. It's to prevent the block from being able to move after instalation. I view dimple/s as an alignment method only personally. Proper torque and thread locker along with proper set screws will do the job. |
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Can't never could 'til try came along.
"All welchers should be removed from the EE".-Aimless R.I.P. to the EE |
[#26]
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