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Posted: 4/19/2021 3:56:33 PM EDT
I hear good things about SLR, any others to consider?
Link Posted: 4/19/2021 4:01:27 PM EDT
I've used the SLR one a few times now, works great, well built. I like the flats on it for clamping into my vice.
Link Posted: 4/19/2021 4:02:35 PM EDT
Another for SLR
Link Posted: 4/19/2021 4:09:19 PM EDT
[Last Edit: 4/19/2021 4:17:34 PM EDT by dms888]
What type of bit you guys using?  I know it's 5/32", but what type of material for the bit?  Cobalt?
Link Posted: 4/19/2021 4:10:40 PM EDT
[Last Edit: 4/19/2021 4:12:07 PM EDT by onthebreeze]
What better to use than the GB itself?

1. Line up middle hole with gas port (upside down).
2. Loosely tighten the other 2 screws to hold GB in place.
3. Place level on flat of GB, level in vice and clamp.
4. Loosen the screws, rotate GB 180° and relevel.
5. Loosely tighten middle screw, mark the other 2, then vice versa.
6. Remove GB, idiot check, and dimple.

Obviously, check clearance from the rear of the GB and space it off with feeler gauges if needed when rotating.
Link Posted: 4/19/2021 4:18:22 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By dms888:
What type of bit you guys using?  I know it's 5/32", but what type of material for the bit?
View Quote

A lot of them haha.. I tried a couple bits from my toolbox and various drill bit sets, most didn't touch a nitride barrel. Eventually I got one to bite some material.
Link Posted: 4/19/2021 6:04:31 PM EDT
There are about 10 different GB screw spacings, the SLR covers the five most common. Make sure your jig spacing coincides with your actual GB spacing, being 0.025" off on the muzzle end dimple is worse than no forward dimple at all. Some, including me, prefer one dimple only just to ensure gas port alignment. For nitride barrels, use a solid carbide drill bit (not the kind used in masonry). You can also break through the nitriding with a file or pointed grinding bit and use a more commonly available quality drill bit.
5/32 solid carbide bit
Link Posted: 4/19/2021 7:20:21 PM EDT
[Last Edit: 4/19/2021 7:22:03 PM EDT by dms888]
Only going to drill one aligned with gas port is the plan.  What about at Cobalt bit compare to a solid carbide bit?
Link Posted: 4/19/2021 9:59:10 PM EDT
[Last Edit: 4/19/2021 10:10:02 PM EDT by Exorpmtech]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By dms888:
Only going to drill one aligned with gas port is the plan.  What about at Cobalt bit compare to a solid carbide bit?
View Quote


I had no issues dimpling phosphate barrels with a standard store bought Irwin drill bit, like my DD.

My Aero barrels with their "QPQ" finish is incredibly hard.  It may be some nitride concoction.   I had to buy a carbide bit just to dimple those barrels.  I had to do some googing to find it.  I did see some on Amazon but didn't try them.

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Link Posted: 4/19/2021 10:56:56 PM EDT
The Aero/BA QPQ barrels are extremely tough. You could try the cobalt, but I would buy 2. I use a lot of Kodiak cutters and bits and they're reasonably priced, but for small orders, it's the shipping that hurts.
Kodiak Cutting Tools
Link Posted: 4/20/2021 6:23:13 AM EDT
[Last Edit: 4/20/2021 6:44:15 AM EDT by Air_Soft_Contractor]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By dms888:
What type of bit you guys using?  I know it's 5/32", but what type of material for the bit?  Cobalt?
View Quote


Use a 5/32" cobalt drill.

A 135 degree drill tip angle should cut better than a standard 118 degree drill tip angle that is used by home owners and woodworkers.

Use a set screw, "drill stop" on the drill and feeler gauge it at 0.115" above the jig, as the tip sits on the undimpled barrel journal.
Link Posted: 4/21/2021 8:05:59 PM EDT
I like the KAK Industry jig.  It accommodates a variety of setscrew spacing distances, and includes a Keo brand spot drill to make the dimples.
Link Posted: 4/22/2021 10:27:26 AM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By GHPorter:
I like the KAK Industry jig.  It accommodates a variety of setscrew spacing distances, and includes a Keo brand spot drill to make the dimples.
View Quote


+1

Bought it for less than most jigs, did 2 barrels and the bit still has plenty of life in it.

Also came with a velcro "KAK" patch so everyone can see I'm a filthy KAK lover.
Link Posted: 4/22/2021 12:49:14 PM EDT
I have a older SLR, believe it is for only two different  spacings.
Link Posted: 4/22/2021 12:55:08 PM EDT
Another vote for the KAK jig, and also using cobalt drill bits on nitride / QPQ / miracle-hard surface treated barrels. You may want to make a starter "divot" with a center punch first.
Link Posted: 4/22/2021 7:06:48 PM EDT
Mark the dimple spot with a sharpie and kiss it with a Dremel cutting wheel. The HSS bits cut just fine after that.

QPQ is hard to get started on. If you are through the surface hardening, it’s just steel.
Link Posted: 4/24/2021 4:27:54 PM EDT
Do both of these jigs have a way to line up the dimpling sites in the correct location relative to the gas port? Dimpling makes me real nervous so Im trying to get an idea of how idiot proof these are
Link Posted: 4/24/2021 5:40:20 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By TheDude315:
Do both of these jigs have a way to line up the dimpling sites in the correct location relative to the gas port? Dimpling makes me real nervous so Im trying to get an idea of how idiot proof these are
View Quote


Every jig and block I’ve ever seen has the first dimple/screw directly opposite the gas port. A conical tip on the set screw helps center the jig on the gas block.

Sometimes, I don’t even bother to do the second dimple if it doesn’t line up with my jig. I do the one opposite the gas port then Rocksett and tighten both screws.
Link Posted: 4/24/2021 8:20:29 PM EDT
Yes.  There’s a setscrew that you turn into the gas port - it’s usually a conical-tipped or pointed screw.  This secures the jig in perfect alignment.  Once that’s set, the jig stays put, and you can depend on the points you dimple to be accurate.
Link Posted: 5/3/2021 11:58:49 AM EDT
[Last Edit: 5/3/2021 12:00:09 PM EDT by MS556]
I'm going to be a contrarian.  If the block is low profile and under a rail, there really is no need to dimple.  If you have proper set screws, they have concave tips that dig into the barrel surface when torqued.  If you've ever removed a low pro gas block where proper set screws were used, you will see circular indentations where they cut into and gripped the barrel.  They hold very firmly.  No, they don't vibrate loose.  The concave tip works like a lock washer, too.

Unless the rail over the gas block is hit so hard that it is knocked loose enough to hit the gas block, the block is not going to move.  Period.

Now, A2 tower gas block sights are, of course, a different story.  They should be drilled and taper pinned.
Link Posted: 5/3/2021 12:26:01 PM EDT
I think of dimpling as helping locate the block precisely, with a little help keeping it secure.  It seems to me to be one of the smoothest and most reliable ways to make sure your block is where it’s supposed to be.
Link Posted: 5/3/2021 12:56:57 PM EDT
+1 for the SLR. It's the only jig I've worked with, but it works extremely well.
Link Posted: 5/3/2021 2:33:55 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By MS556:
I'm going to be a contrarian.  If the block is low profile and under a rail, there really is no need to dimple.  If you have proper set screws, they have concave tips that dig into the barrel surface when torqued.  If you've ever removed a low pro gas block where proper set screws were used, you will see circular indentations where they cut into and gripped the barrel.  They hold very firmly.  No, they don't vibrate loose.  The concave tip works like a lock washer, too.

Unless the rail over the gas block is hit so hard that it is knocked loose enough to hit the gas block, the block is not going to move.  Period.

Now, A2 tower gas block sights are, of course, a different story.  They should be drilled and taper pinned.
View Quote



I am 100% in agreement.  The dimple serves to help align the gas block, but that is easy enough to do without one.
Link Posted: 5/6/2021 9:30:14 PM EDT
[Last Edit: 5/6/2021 9:32:08 PM EDT by TheDude315]
I just used the SLR one today. It was fantastic. Last time I tried to swap a gas block I wasn't able to get it lined up. With the SLR it took me 15 seconds with a Cobalt bit to make 2 perfect dimples. I slid on the gas block, lined up.the dimples and immediately had perfect gas port alignment. If only inserting the gas tube roll pin was so easy. I destroyed about 80% of it getting it in
Link Posted: 5/7/2021 10:24:26 AM EDT
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Originally Posted By s4s4u:
I am 100% in agreement.  The dimple serves to help align the gas block, but that is easy enough to do without one.
View Quote

I don’t know about “easy enough”, at least for me.  All of them I’ve installed were a tight enough fit that I was concerned about whether I could get the block properly lined up vertically and still in the correct position relative to the shoulder on the barrel.

Basically I like the objectiveness of dimples.  They reassure me that the block is positioned correctly.
Link Posted: 5/7/2021 10:40:01 AM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By dms888:
Only going to drill one aligned with gas port is the plan.  What about at Cobalt bit compare to a solid carbide bit?
View Quote


Cobalt will not even put a mark on a nitride barrel.

I had to get a carbide bit to dimple all of my ballistic advantage barrels. Expensive, but works extremely well so its worth the investment.

I also vote for SLR. Very well built.
Link Posted: 5/7/2021 11:51:15 AM EDT
Meh, i've dimpled 2 Aero nitirde barrels and several other manufacturers black nitride finish. It is a hard surface, but it's no hill for a stepper. Especially if you have a drill press and some decent cutting lube. Cobalt drill bits are fine. I think I use Bosch.

+1 on the SLR jig.
Link Posted: 5/10/2021 5:22:15 AM EDT
I like the SLR because you can't wear it out.  The screws take the wear from your drill bit and SLR has cheap replacement screws on their website so you won't have to buy a new jig.
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