Suppressors DIY Suppressor alignment gauges

[England]

I'd found a thread on Reddit about using O-1 tool steel rods to make your own suppressor alignment gauges. I have the Geissele .22 and .308 rods, but needed one for 6.5 barrels. I'd been making do with using my .22 rod and rotating the rifle 90 degrees four times to check alignment.

The rods are available from McMaster-Carr and quite reasonable: https://www.mcmaster.com/catalog/126/3946/

The Geissele rods look like they may well be made from the same material, and are 17" long. A friend is diving into precision shooting and planning to get a suppressor. McMaster sells these in 3' and 6' lengths, so I figured I would try the 36" rods and if it worked, I could give him a set of gauges.

When you order these, be sure to consider the barrel's bore diameter, not the groove-to-groove diameter! For a .22 centerfire, that would be 0.219". For my 6.5 barrels, 0.256" (so the 0.257" rod would lead to impolite language). For our .308 Win, .30-06, .300 BO, .300 WSM, and such, 0.300".

I ordered four rods: (Tight-Tolerance Oil-Hardening O1 Tool Steel Rod)

1 8893K204 0.250" Diameter, 3 Feet Long $4.53

2 8893K191 0.2120" Diameter, 3 Feet Long $5.66 (figured this for .22 centerfires and most rimfire)

3 8893K187 0.2031" Diameter, 3 Feet Long $5.13 (figured this for .22 rimfire with a tight "match" barrel)

4 8893K217 0.2950" Diameter, 3 Feet Long $7.00

Merchandise 22.32
Sales Tax 1.34
Shipping 9.72
Total $33.38

They showed up today. Now, someone like with skills, pride, and a good shop would neatly and precisely cut these for a perfect cylindrical shape, like the Geissele rods. But that's not me. So I marked 18" with a Sharpie, clamped the rod in the vice, and went to work with the SawZall and a metal blade. Then I fired up the bench grinder and cleaned up and chamfered the ends. No, you wouldn't pay $70 each for these rods, but that was kind of the point.

I have a 6"x18" granite plate with "flatness certificate" I got on a deal from Woodcraft for sharpening chisels and planes. I put each rod on the plate, rolled it, and backlit with a handy tactical flashlight. They appear quite straight; certainly straight enough for my intended purpose!

I washed each rod and then coated them with Boeshield T9. More importantly, I put a 6.5 CM rifle in my vice, screwed on the suppressor, and slipped in the 0.250" rod. Happily, the rod inserted into the barrel snugly but cleanly and unsurprisingly, the suppressor appears to be nearly perfectly aligned. Which is probably why I haven't shot it to pieces already.

I'm planning to get some PVC end caps and will make a couple 18+" tubes to hold each set of four rods. But at $17 for a set of four, they are marvelously cheaper than commercial rods and even a hack like me can turn one out.

 

[phantasm]

I've been thinking of doing the same thing but wasn't too sure which rods to go with. I assume the .2950" diameter rod is for 30 cal? I've looked at the Geissele and Griffin rods and while they look nice, holy hell on that price tag.

 

[England]

That 0.295" rod works fine for .308 Win/.30-06/.300 BO and the like. It is a snug but safe fit.

 

[Supersubes]

That 0.295" rod works fine for .308 Win/.30-06/.300 BO and the like. It is a snug but safe fit.

That’s hotdog down a hallway undersized if you ask me. Not even close to bore diameter.

 

[gconnoyer]

Go to a local archery store and find some carbon arrows the size you need.
Runout is typically .001-.005 (highest quality to lowest)
Suppressor overbore is typically .060 over

I've got a .259 dia shaft that would work more than good enough for 6.5creed (I'm not archer so I'm not sure on available sizes and how they match up to bullet bore size

 

[England]

That’s hotdog down a hallway undersized if you ask me. Not even close to bore diameter.

Bore diameter is 0.300". The rod is 0.295", so 0.005" clearance. Are you really suggesting that an additional 0.004" is necessary as a no-go suppressor gauge? You're much braver than me or don't mind launching the occasional can downrange.

 

[Supersubes]

Bore diameter is 0.300". The rod is 0.295", so 0.005" clearance. Are you really suggesting that an additional 0.004" is necessary as a no-go suppressor gauge? You're much braver than me or don't mind launching the occasional can downrange.

Why would a more precise rod put you at risk of launching a suppressor? And yes I’m suggesting that .295 is way too small for what Im doing.

 

[EnXCess]

Uh, I hate to tell you but I can mount a suppressor and then simply look through it and the bore and tell you whether it is on straight or not. That's easy with a bolt gun, a little harder with an a/r.

Also, I would be concerned about damaging my rifling if I put in a steel rod that fit tight enough to do any good.

 

[Supersubes]

Uh, I hate to tell you but I can mount a suppressor and then simply look through it and the bore and tell you whether it is on straight or not. That's easy with a bolt gun, a little harder with an a/r.

Also, I would be concerned about damaging my rifling if I put in a steel rod that fit tight enough to do any good.

You mean like the steel range rods most gunsmiths put down the bore to dial it in to the lathe, which have .0002-.0004 clearance? How bout a rod with .001 clearance, not .005, and with a high degree of straightness?

 

[EnXCess]

You mean like the steel range rods most gunsmiths put down the bore to dial it in to the lathe, which have .0002-.0004 clearance? How bout a rod with .001 clearance, not .005, and with a high degree of straightness?

Correct. I would not do that either unless there were some good reason to, like threading a barrel.

 

[Doug308]

I'd found a thread on Reddit about using O-1 tool steel rods to make your own suppressor alignment gauges. I have the Geissele .22 and .308 rods, but needed one for 6.5 barrels. I'd been making do with using my .22 rod and rotating the rifle 90 degrees four times to check alignment.

The rods are available from McMaster-Carr and quite reasonable: https://www.mcmaster.com/catalog/126/3946/

The Geissele rods look like they may well be made from the same material, and are 17" long. A friend is diving into precision shooting and planning to get a suppressor. McMaster sells these in 3' and 6' lengths, so I figured I would try the 36" rods and if it worked, I could give him a set of gauges.

When you order these, be sure to consider the barrel's bore diameter, not the groove-to-groove diameter! For a .22 centerfire, that would be 0.219". For my 6.5 barrels, 0.256" (so the 0.257" rod would lead to impolite language). For our .308 Win, .30-06, .300 BO, .300 WSM, and such, 0.300".

I ordered four rods: (Tight-Tolerance Oil-Hardening O1 Tool Steel Rod)

1 8893K204 0.250" Diameter, 3 Feet Long $4.53

2 8893K191 0.2120" Diameter, 3 Feet Long $5.66 (figured this for .22 centerfires and most rimfire)

3 8893K187 0.2031" Diameter, 3 Feet Long $5.13 (figured this for .22 rimfire with a tight "match" barrel)

4 8893K217 0.2950" Diameter, 3 Feet Long $7.00

Merchandise 22.32
Sales Tax 1.34
Shipping 9.72
Total $33.38

They showed up today. Now, someone like with skills, pride, and a good shop would neatly and precisely cut these for a perfect cylindrical shape, like the Geissele rods. But that's not me. So I marked 18" with a Sharpie, clamped the rod in the vice, and went to work with the SawZall and a metal blade. Then I fired up the bench grinder and cleaned up and chamfered the ends. No, you wouldn't pay $70 each for these rods, but that was kind of the point.

I have a 6"x18" granite plate with "flatness certificate" I got on a deal from Woodcraft for sharpening chisels and planes. I put each rod on the plate, rolled it, and backlit with a handy tactical flashlight. They appear quite straight; certainly straight enough for my intended purpose!

I washed each rod and then coated them with Boeshield T9. More importantly, I put a 6.5 CM rifle in my vice, screwed on the suppressor, and slipped in the 0.250" rod. Happily, the rod inserted into the barrel snugly but cleanly and unsurprisingly, the suppressor appears to be nearly perfectly aligned. Which is probably why I haven't shot it to pieces already.

I'm planning to get some PVC end caps and will make a couple 18+" tubes to hold each set of four rods. But at $17 for a set of four, they are marvelously cheaper than commercial rods and even a hack like me can turn one out.

With the sizes you selected, how was the fit with the .308 and .223 ?

 

[PlinkIt]

I understand @Supersubes using the precision rods, and if you are doing work in a lathe you really should not be using drill rod

But...

For rednecks such as myself...

And when you have one that is OFF it's rather obvious that it is OFF

Even if you have a barrel that gives a good bit of clearance all you have to do is rotate the rod around a little and you will see it either maintain the same gap as it rolls OR like in this case it stays pinned to one side no matter what. I mean like I der tension pinned!

I left my rods the full 3ft and just sanded and rounded one end of the rod. I stand the rifle barrel up and drop the rod down the bore to sit on the bolt face. Figure I'll have a good fitting rod of I ever need to drive something out of my barrel as well.

The 9mm, 6.5, 308, and 22lr / 223 rods I've used on several rifles as a safety check and so far only caught the one

 

[smoooth1]

Carbon arrow shafts work great as well.

 

[les_garten]

I'm waking up this thread because I have a question and it looks like a good thread to keep current.

What diameter rod for a 9mm?

 

[FuhQ]

I'm waking up this thread because I have a question and it looks like a good thread to keep current.

What diameter rod for a 9mm?

Semi-auto 9mm (and .357 Sig) is .355” dia bullets, and .357 Magnum, Maximum, & .350 Legend use .357 to .358” dia bullets.

Not sure about the proper alignment rod diameter though.

 

[les_garten]

Semi-auto 9mm (and .357 Sig) is .355” dia bullets, and .357 Magnum, Maximum, & .350 Legend use .357 to .358” dia bullets.

Not sure about the proper alignment rod diameter though.

Maybe .350 or so?

 

[FuhQ]

Maybe .350 or so?

Honestly, no idea.

 

[PlinkIt]

I'm waking up this thread because I have a question and it looks like a good thread to keep current.

What diameter rod for a 9mm?

As I said above this is NOT for alignment for lathe work...

But the .343 drill rod from mcmaster left long and dropped to the bolt face should be good enough to show you if alignment is out or not. The amount of angle allowed from the length of the entire barrel even being a few thou smaller doesn't stop you from being able to judge alignments enough to avoid baffle strikes and such

Then when you have one like the picture I posted above you know to take that apart / change parts / send to machinist / etc

 

[B y r o n]

Here is some data I've put together regarding McMaster Carr part numbers:

Caliber​	Bore Dia​	Drill Rod Dia​	Part #​
​	​	​	​
17​	0.1680​	​	​
22 Rimfire​	0.2160​	0.2120​	8893K191​
22 Rimfire Mag​	0.2180​	​	​
22 Centerfire​	0.2190​	0.2188​	8893K193​
243/6mm​	0.2370​	0.2362​	88625K65​
25​	0.2500​	0.2460​	8893K202​
6.5​	0.2560​	0.2500​	8893K204​
270​	0.2700​	0.2660​	8893K209​
7mm​	0.2770​	0.2770​	8893K212​
30​	0.3000​	0.2969​	8893K219​
7.62/302​	0.3020​	0.3020​	8893K221​
303​	0.3030​	​	​
32-40​	0.3120​	​	​
8mm​	0.3150​	0.3125​	8893K223​
338​	0.3300​	0.3281​	8893K227​
9mm​	0.3470​	0.3438​	8893K231​
357​	0.3500​	0.3480​	8893K233​
10mm/40 cal​	0.4000​	0.3906​	8893K244​
45 Pistol​	0.4420​	0.4375​	8893K254​

 

[strikeeagle1]

I use the Geissele alignment rods for non-.22LR barrels. I also have used McMaster Carr's tight-tolerance rod stock. As mentioned above, the 0.2120" diameter works well for the common .22 rimfire. Geissele instructions for their SAR rods suggests using "minute of eyeball" confirmation that the rod is concentric with the suppressor muzzle. I found interesting that shims between shoulders of barrel-suppressor can change the concentricity between the rod-bore and suppressor muzzle, allowing them to optimize "timing"between the two.

 

[VicC55]

Reviving this thread. 30/9/23
.2188 for the 5.56 I have 3
& the .2995 for the 300 blk out I have only 1,
All set up for cans, the 300 has a dedicated can the 5.56's share,
both rods are Tight as "F" and need to be spun to them get in.
Both from McMaster's. $25.50 shipped Ordered on a Sunday received Wednesday.
Cheaper than $69-$75 each and serve the same purpose.

 

[strikeeagle1]

both rods are Tight as "F" and need to be spun to them get in.

IF you haven't already, I found it useful to put a chamfer on the end of the tight tolerance rods and use some lubricant for insertion.

 

[VicC55]

IF you haven't already, I found it useful to put a chamfer on the end of the tight tolerance rods and use some lubricant for insertion.

I did, I chamfered both ends on both rods but I didn’t get the chance to test them yet. Thanks