Anyone know where I might be able to buy a reasonably priced barrel dimpling jig for a 0.75” AR gas journal here in Canada? I’ve searched everywhere and I can only find two: TNA has one for a great price that’s out of stock and CTC Supplies is selling a Rainer Arms branded one for $69.99 (more than I’d care to spend).
Barrel Dimpling Jig
- Thread starter YKBrute
- Start date
I was gonna pick one up for my build also but have been reading that dimpling in not a mandatory procedure. If you feel it is in you case then by all means but just throwing it out there. I'm building mine undimpled with cutter type set screws. Then just plan to inspect periodically.
Corey
Corey
Yeah I hear ya. Leaning towards that way if I can’t find anything cheap. Just wanting to ensure that I have perfect gas block alignment. I’m kind of the particular type of you know what I mean.
I bought this one from CTCS and I think it's worth the money. The picture on their website is of the old version.
The Brownells dimpling jig is $55 USD and is the old version. It will cost you more by the time you get it here than the one from CTCS will cost you.
If you're only doing 1 barrel I wouldn't even bother but if you plan on using it for a few or using it for more builds sometime later on I think it's worthwhile having 1 around.
Just my .02
The Brownells dimpling jig is $55 USD and is the old version. It will cost you more by the time you get it here than the one from CTCS will cost you.
If you're only doing 1 barrel I wouldn't even bother but if you plan on using it for a few or using it for more builds sometime later on I think it's worthwhile having 1 around.
Just my .02
I've done it a few times now without a jig and I've had no trouble.
Measure your gap between the end of the gas block journal & gas block itself with a feeler gauge while the gas block is installed upside down so you can line up the holes. Mark the center of the hole in your barrel with a pencil line on the barrel. Reposition the gas block right side up, get it centered on your line and set it back the proper distance with the feeler gauge and tighten the screws down. Now reach into the upper and block the chamber with your pinkie finger and blow down the muzzle (make sure if you have an adjustable gas block it's adjusted to be open). If you've messed up the positioning you shouldn't feel any air coming out of the gas tube in the upper. If there is a free flow of air you are probably fine.
Just take out one set screw at a time (leaving the other tight so it doesn't move) and carefully mark your barrel through the gas block.
Not sure I would ever spend 70$ on a jig... Maybe if I was doing 10 per day.
Measure your gap between the end of the gas block journal & gas block itself with a feeler gauge while the gas block is installed upside down so you can line up the holes. Mark the center of the hole in your barrel with a pencil line on the barrel. Reposition the gas block right side up, get it centered on your line and set it back the proper distance with the feeler gauge and tighten the screws down. Now reach into the upper and block the chamber with your pinkie finger and blow down the muzzle (make sure if you have an adjustable gas block it's adjusted to be open). If you've messed up the positioning you shouldn't feel any air coming out of the gas tube in the upper. If there is a free flow of air you are probably fine.
Just take out one set screw at a time (leaving the other tight so it doesn't move) and carefully mark your barrel through the gas block.
Not sure I would ever spend 70$ on a jig... Maybe if I was doing 10 per day.
angryeyebrows
CGN frequent flyer
- Location
- Oscar Mike
Generally speaking, a low profile gas block will have an oversized hole. Super accurate alignment is not critical for proper function. This includes leaving any sort of gap, between the block and the shoulder on the barrel. That being said, you should ensure that it is as plumb as you can for two other reasons; avoiding contact with the inside of a narrow rail system, and so the gas tube enters the upper receiver as straight as possible. As for dimpling, with set screw type gas blocks, you should always dimple the barrel for durability. It can be an intimidating step for a hobbyist gun builder, so professional services should be considered.
Gas block jigs are handy, but not totally required. If you foresee yourself using it again in the future, I say go for it. It’s just like buying proper gas block punches, you can get by with makeshift tools, but the proper tool makes the job much easier.
Gas block jigs are handy, but not totally required. If you foresee yourself using it again in the future, I say go for it. It’s just like buying proper gas block punches, you can get by with makeshift tools, but the proper tool makes the job much easier.
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Dimpling is not really about the alignment of the gasblock. It is so the set screw style gasblocks dont eventually walk forward.
Thanks for your input everyone. I’ve shelved the dimple plan (for now). I sighted my alignment by removing one of the set screws, observing the gap between the block and end of the journal, then rotated the block 180 degrees. Turns out the gap was about the thickness of a Fender light guitar pick! 
3k rounds on my first upper build, 0 issue, .625 gas block no dimpling.
New upper has ~800 through it, 0 issues (other than working out buffer/spring issues with weight), .625 gas block no dimpling.
I would have preferred to dimple them as a security measure, but so far it hasn't been needed and saved me cash on a tool. The gas block screws are still tight, no signs of backing out.
New upper has ~800 through it, 0 issues (other than working out buffer/spring issues with weight), .625 gas block no dimpling.
I would have preferred to dimple them as a security measure, but so far it hasn't been needed and saved me cash on a tool. The gas block screws are still tight, no signs of backing out.
In the same situation currently forgot to add one on my Brownells order, so after doing lots of looking around on the internet. I think I am better off spending an hour on the manual mill and I'll be making my own
Unless someone can point us to a Canadian retailer that actually has some in stock? I am looking for .75 and .4 spacing
So far all the barrels I have used set screw gas blocks on have had at least one dimple aligned with the gas port already done. I am not sure if the MRA barrel I have on the way is dimpled at all, but I always prefer to go the extra step and dimple if I am using a set screw gas black, at least the one
Unless someone can point us to a Canadian retailer that actually has some in stock? I am looking for .75 and .4 spacing
So far all the barrels I have used set screw gas blocks on have had at least one dimple aligned with the gas port already done. I am not sure if the MRA barrel I have on the way is dimpled at all, but I always prefer to go the extra step and dimple if I am using a set screw gas black, at least the one
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I don't get the use of a jig, personally.
I use the gas block I'm going to use as a template to dimple the barrel along with a bit that just fits the threaded hole for the set screw, but doesn't interfere with the threads.
1) Assemble barrel, nut, gas block and gas tube. Ensure there is no binding of the tube on the bolt carrier when the carrier is installed in the upper.
2) install one set screw with light pressure to hold block in place and use a drill on other hole creating your first dimple.
3) Install second set screw to hold the block and then take out the first set screw and drill the second dimple.
4) take the block and gas tube off to clean the rifle and parts of any shavings still hanging around and then re-install it all back with your choice of thread locker.
I use the gas block I'm going to use as a template to dimple the barrel along with a bit that just fits the threaded hole for the set screw, but doesn't interfere with the threads.
1) Assemble barrel, nut, gas block and gas tube. Ensure there is no binding of the tube on the bolt carrier when the carrier is installed in the upper.
2) install one set screw with light pressure to hold block in place and use a drill on other hole creating your first dimple.
3) Install second set screw to hold the block and then take out the first set screw and drill the second dimple.
4) take the block and gas tube off to clean the rifle and parts of any shavings still hanging around and then re-install it all back with your choice of thread locker.
My MRA Barrel wasn’t dimpled.
Thanks I didn't think so from what pictures I've seen online
My barrel and gas block came in today and its a great example of why I wont use the gas block as the jig to drill the dimples
As you can see I have the gas block pushed as far onto the barrel as possible, and the gas port alignment is still off, if I simply put on and aligned it left to right, and drilled the hole using the set screw hole, I would have dimpled it in the wrong spot
I want to make sure I get the first dimple 100% aligned with the gas port.
There seems to an interference not allowing my port top line up, the chamfer on the inside of the gas block looks like it can be a little bigger and allow it to slide on a bit more. I will be doing that tomorrow, and see if its enough to get them to align properly, if not I will shave a bit off the gas block until it aligns.
mixing different brand parts can have tolerance issues, this is a Maple Ridge Armory barrel and a SLR rifleowrks gas block
As for the tool, I bought a bearing collar with a .75" bore and one set screw from Princess Auto for $4.50 today, the fit to the barrel journal is tight. So tomorrow I will be drilling a hole right through the middle of the set screw and collar on a manual mill, turning it into a dimple jig...
Gunnerlove
CGN Ultra frequent flyer
- Location
- Vancouver Island
Looks fine. The gas is going to make it to the gas tube.
the gas port hole is much smaller then that set screw hole, so it would get covered slightly
It may function properly it may not, I spent $5000 on parts for this rifle, I am not going to cut such a small corner now. Especially since its a time thing not a cost thing, making a tool myself cost me $4.50 and some of my time
To each their own, I would personally prefer to align it better if not %100. That's just me, not saying its the way everyone has to do it, or that it wont work.
