I received my 24" Sabre Defence Grendel barrel and I have a .936" PRI gas block. The issue I am having is that the SD barrel has no index flats for the gas block set screws. I am worried about aligning the gas port in the bbl with that on the block. Anyone care to share their expertise in installing as gas block in this situation?
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Gas block install
- Thread starter Sgt_Jamez
- Start date
Re: Gas block install
I used a fine tipped permanent marker to draw a centerline down the OD of the barrel in line with the gas port for my AR15 when I replaced the military front sight with a low profile gas block. I haven't had any issues with it in about 900 rounds. MIght not be the best way to do it, but it seems to function and accuracy is good.
I used a fine tipped permanent marker to draw a centerline down the OD of the barrel in line with the gas port for my AR15 when I replaced the military front sight with a low profile gas block. I haven't had any issues with it in about 900 rounds. MIght not be the best way to do it, but it seems to function and accuracy is good.
Re: Gas block install
Ok cool. So that gives me rotational alignment. Can I just run the block against the shoulder of the barrel? Not sure how far back to go with the block.
Ok cool. So that gives me rotational alignment. Can I just run the block against the shoulder of the barrel? Not sure how far back to go with the block.
Re: Gas block install
I think (this is the way my RRA is) that you have to leave "a little" space between the gas block and the shoulder because they're spec'd to have the handguard cap between the gas block and the shoulder. I used a calipers to measure everything, not thinking that I still had the cap from the old handguards to use as a spacer.
I think (this is the way my RRA is) that you have to leave "a little" space between the gas block and the shoulder because they're spec'd to have the handguard cap between the gas block and the shoulder. I used a calipers to measure everything, not thinking that I still had the cap from the old handguards to use as a spacer.
Re: Gas block install
By the book .030 from the shoulder but most blocks can be pushed flush and line up fine. Do the math. Might want to pre assamble the gas tube and check alignment between the tube and block hole. I use a taper ream to open up the tube to match the block. and then lock tight the block to the barrel. blow air down the tube to clear it after assembly.When in doubt you can hook air to the tube and tune it for max flow by ear.
Scot
By the book .030 from the shoulder but most blocks can be pushed flush and line up fine. Do the math. Might want to pre assamble the gas tube and check alignment between the tube and block hole. I use a taper ream to open up the tube to match the block. and then lock tight the block to the barrel. blow air down the tube to clear it after assembly.When in doubt you can hook air to the tube and tune it for max flow by ear.
Scot
Re: Gas block install
Most gas blocks have a hole quite a bit larger than the gas port on the barrel. Get it centered, push it flush..or a little off. If it works great, then you can worry about something else.
Most gas blocks have a hole quite a bit larger than the gas port on the barrel. Get it centered, push it flush..or a little off. If it works great, then you can worry about something else.
Re: Gas block install
Get your gas block in hand, use your calipers to measure the distance from the front edge of your gas block to the center gas port hole, record this measurement. Get your barrel, measure from the center of the gas port forward the same distance you recorded earlier, scribe a line with a #2 pencil. Slide your gas block on until the front edge lines up with the scribed line on the barrel. Done.
Get your gas block in hand, use your calipers to measure the distance from the front edge of your gas block to the center gas port hole, record this measurement. Get your barrel, measure from the center of the gas port forward the same distance you recorded earlier, scribe a line with a #2 pencil. Slide your gas block on until the front edge lines up with the scribed line on the barrel. Done.
Re: Gas block install
Awesome! I think I can handle that operation. My receiver comes in today so I'll be red loctite-ing the VTAC to the receiver tonight for the assembly tomorrow.
Awesome! I think I can handle that operation. My receiver comes in today so I'll be red loctite-ing the VTAC to the receiver tonight for the assembly tomorrow.
Re: Gas block install
Rainer Arms makes a Gas Block indexing pin tool.
Check the website.
Looks like this.
You line the top hole up with the gas hole and then scew in the other screws to make your indents.
Perfect alignment!
Also I wouldnt Red locktite for anything on an AR. Use the Blue Locktite if your going to use it.
Rainer Arms makes a Gas Block indexing pin tool.
Check the website.
Looks like this.
You line the top hole up with the gas hole and then scew in the other screws to make your indents.
Perfect alignment!
Also I wouldnt Red locktite for anything on an AR. Use the Blue Locktite if your going to use it.
Re: Gas block install
Red Loctite is called for on the VTAC forend instructions. There's a body that threads onto the the receiver, and the barrel nut threads to that body. They note that the red Loctite is to prevent any movement during the torqueing of the barrel nut.
Red Loctite is called for on the VTAC forend instructions. There's a body that threads onto the the receiver, and the barrel nut threads to that body. They note that the red Loctite is to prevent any movement during the torqueing of the barrel nut.
Re: Gas block install
Slick tool Longrange. You know if it's sized for .936" bbls? I read the site and install doc and nothing spells out what size bbl it goes with.
BTW... what kind of buffer/buffer spring are you guys running?
Slick tool Longrange. You know if it's sized for .936" bbls? I read the site and install doc and nothing spells out what size bbl it goes with.
BTW... what kind of buffer/buffer spring are you guys running?
Re: Gas block install
Second on not using red loctite. Ifyou ever have to take it apart you will regret using it. Blue is plenty strong enough.
Second on not using red loctite. Ifyou ever have to take it apart you will regret using it. Blue is plenty strong enough.
Re: Gas block install
Dang... red loctite has been curing since yesterday afternoon. Blue is strong enough to take the barrel nut torqueing without allowing the body to rotate?
Dang... red loctite has been curing since yesterday afternoon. Blue is strong enough to take the barrel nut torqueing without allowing the body to rotate?
Re: Gas block install
I'm pretty fond of the VTAC handguard so it will most likely never be removed.
I'm pretty fond of the VTAC handguard so it will most likely never be removed.
Re: Gas block install
I used a borescope thru the barrel to line up the hole in the barrel with the hole in the gas block on LAR-8. Looking at it afterward, the block is against the shoulder.
I used a borescope thru the barrel to line up the hole in the barrel with the hole in the gas block on LAR-8. Looking at it afterward, the block is against the shoulder.
