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In anticipation of another can I have coming I moved a couple mounts around and put a new one on the MPW. Put the can on and 'eyeball' you can. But the last thing you want is to have a baffle strike or blow out your end cap. So in order to really satisfy ones ocd and be sure things are true you of course need a tool. Concentricity is the term and that is how straight things are all the way thru the bore and can.

This is where a little research saved me $65 and shipping. Some may argue but the specs are the same.

Here we have the marketed Geissele 'tool'. Basically a $75 dollar steel rod. Yeah it's ground to within .001 all the way down and straight and it fits perfectly in the bore without wiggle.

http://www.brownells.com/gunsmith-tools-supplies/rifle-tools/barrel-tools/7-62mm-suppressor-alignment-rod-prod72375.aspx

But then we have what I found on Amazon for $9.95 shipped free.

https://www.amazon.com/gp/aw/d/B0050RIOFG/ref=yo_ii_img?ie=UTF8&psc=1

This is also a hardened steel rod ground to within .001 and as straight as can be.
The Geissele tool is only 17 inches long so if your gonna check a bolt gun you won't be able to get a full length look at things. The Amazon rod is 36 inches long. So it will work for just about anything.

Now first this is a 'cheaper' rod in the sense it's not made specifically for this purpose. So it's a good idea to check the ends with a caliper to make sure they didn't get squeezed or widened during the cut. Also looks for burrs on the ends. Again it's hardened steel and will score your bore if there's a burr. That's the only 'benefit' for the Gesseile tool. It's a polished rod made for this purpose so out of the box it's GTG. Fortunately for me though my cheapo rod was true and had perfect ends out of the tube. It was a little dry and dirty. You can tell it came from a factory. So a good cloth and some clp along with a few swipes up and down cleaned it up and smoothed it down.

I say tube because it came wrapped in a rust prohibitive type paper ala Smith & Wesson and inside a really nice HD tube which will work perfect for a storage unit.



A pic of the rod coming out showing it..


Now what you are supposed to do is bring rod end right to end cap and see.
If the rod is perfectly centered in end cap hole things are concentric and you should be GTG. If it's touching any of the sides of the end cap opening or won't pass thru at all that's a FAIL and you must realign things to be ok.

So here's a pic of the mount and can as well as rod tip right there.
Perfect and centered. I'm satisfied and good to go.



So the specs on straightness for both are to within .001 all the way down.
Diameter on the Geissele rod is .297. And the diameter on the Amazon rod is .2968.
2/10,000 of a difference was negligible as with a light coat of RemOil it fit perfectly in the bore without wiggle or movement.

I am still in search of a perfect matching diameter rod to the 5.56 one Geissele makes.
The first one I got was smaller by a few thousandths and wiggles a bit which is not a good indicator. So for now I figured I'd share my cost savings way to make sure things are true and centered on .30 caliber guns and save some money while doing it.
 

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Excellent and informative post. Thanks for taking the time to do it!
 

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That is a nice find.

Nothing magical to concentricity tools, other than the price premium that the makers seem to place on them.

For the 5.56 rod, you can always go to a machine shop and have them turn a 24" steel or aluminum rod down to .2182 +/- .005, which would give you a nice slip fit with almost no play (Nominal bore diameter for 5.56 is .219"). Aluminum would be easier to store, as it will not corrode under most circumstances.
 

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Discussion Starter #4
That is a nice find.

Nothing magical to concentricity tools, other than the price premium that the makers seem to place on them.

For the 5.56 rod, you can always go to a machine shop and have them turn a 24" steel or aluminum rod down to .2182 +/- .005, which would give you a nice slip fit with almost no play (Nominal bore diameter for 5.56 is .219"). Aluminum would be easier to store, as it will not corrode under most circumstances.
The Geissele 5.56 rod is .2157
http://www.brownells.com/gunsmith-tools-supplies/rifle-tools/barrel-tools/5-56mm-suppressor-alignment-rod-prod68033.aspx

I got this one from Amazon which is the closest to that I could find.
https://www.amazon.com/gp/aw/d/B0050RJ5WM/ref=yo_ii_img?ie=UTF8&psc=1&th=1

It's .21875 and was too big.
That magical .2175 diameter seems to be difficult to find.
Now I did find a 5.5 mm one that comes out to be like .2179 or something but I think it would still be too big.
So yeah I'll probably start looking for a machine shop around town to see if they can and how much it would be.
For $9.95 shipped free Amazon rocks. :)
 

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For your .21875 rod maybe try this. It sounds like it's useless to you as-is anyway so perhaps worth a shot.
 

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Great info, as I will be traveling this road shortly. Thank you, sir!
 

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Discussion Starter #7
For your .21875 rod maybe try this. It sounds like it's useless to you as-is anyway so perhaps worth a shot.
Interesting. But I wonder about the cost or toxicity of the chems?
The .22 rod was only like $7 shipped at that diameter.
I'll find one soon enough I'm sure.
 

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Didn't think you would have to do this on a modern firearm, but it does make sense especially if the tooling is a little off on the either the barrel or supressor
 

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Didn't think you would have to do this on a modern firearm, but it does make sense especially if the tooling is a little off on the either the barrel or supressor
Most quality manufacturers of firearms and suppressors, you don't have to really, in my humble opinion. But specifically on the AK platform, they pretty much all recommend you do so.

However, it seems Dead Air might be addressing that issue, at least on quality AKs, over the summer.
 

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Discussion Starter #10
Didn't think you would have to do this on a modern firearm, but it does make sense especially if the tooling is a little off on the either the barrel or supressor
Most quality manufacturers of firearms and suppressors, you don't have to really, in my humble opinion. But specifically on the AK platform, they pretty much all recommend you do so.

However, it seems Dead Air might be addressing that issue, at least on quality AKs, over the summer.
For the most part you're right. The guns, the muzzle brake or FH mounts and suppressors are all made pretty well these days.
The AAC mounts don't need to be timed nor do they require crush washers. But the Surefire mount I just did on my Pws .308 required a certain combo of crush washers in order to get it properly timed. If the washers don't crush right or they cant the mount even just a bit once you get to the end of the suppressor which can be several inches the amount things are off have multiplied. This may result in a baffle strike or an end cap impact. So I'd say for some you do some you don't need it.
If the $75 rod was still the only option I would have passed. A one time check tool I ain't paying $75 for.
But for less than $10 shipped how can you even consider saying no for a second? $200 stamp and a $1000 can I'll definitely pay $10 to check em before I possibly destroy one.

Not to mention that the idea is to get the bullet to pass perfectly thru the end cap hole for maximum accuracy.
 

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The Geissele 5.56 rod is .2157
http://www.brownells.com/gunsmith-tools-supplies/rifle-tools/barrel-tools/5-56mm-suppressor-alignment-rod-prod68033.aspx

I got this one from Amazon which is the closest to that I could find.
https://www.amazon.com/gp/aw/d/B0050RJ5WM/ref=yo_ii_img?ie=UTF8&psc=1&th=1

It's .21875 and was too big.
That magical .2175 diameter seems to be difficult to find.
Now I did find a 5.5 mm one that comes out to be like .2179 or something but I think it would still be too big.
So yeah I'll probably start looking for a machine shop around town to see if they can and how much it would be.
For $9.95 shipped free Amazon rocks. :)
May want to slug your barrel.

You can pick up a few soft lead sinkers and drive them through your barrel with a wood dowel.

The diameter between the deep grooves of the slug will give you your bore diameter.
 

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Discussion Starter #12
I've got another 2 months left before the stamps come back for the 5.56 can coming.
Moving around the two .30 caliber mounts was needed because I have one coming back any day now.
But that's a neat idea. I've heard the term before but never really gave it much thought as I had no need.

I'll have 3 5.56 guns when done. Might be neat to slug all three and see what we see.
How accurate is that method?
 
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