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jtallen83

Torquing Down QD Muzzle Devices

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Decided to swap around some gas blocks so I have been removing and replacing several of my AAC 51T muzzle devices. I time them with shims, even the plain flash hiders because I'm anal about it, no other good reason to do it, or so I thought. When I took the flash hider of my X-Caliber barrel I realized it had been torqued down on the muzzle crown and not the shoulder and shims like I had thought, not sure how I missed that but I did. No worry about damaging the crown as it is recessed but the alignment of the suppressor had been borderline when checked with a gauge. I also noticed the carbon build up was very uneven with one side of the muzzle buried and the other almost clean. Used a more substantial shim and confirmed I am on the shoulder and not the crown now. The alignment gauge is very close to dead center on the can now, a big improvement. I found it strange the crown was off while the shoulder was good, must have been a different operation in the production of the barrel. Hope I get a chance to check accuracy and POI shift this trip home, I will report back when I do whenever it happens. 

Curious what others experiences are with torquing muzzle devices, how much, against the shoulder or crown, and have you seen changes with torque values or seating location on accuracy and suppressor alignment?

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I use these, almost exclusively now. I don't even look at crush washers anymore, or peel washers.  These things are the sheeeeiiit.

With these things, you base it off the largest shim, and calculate from there - they include a chart, for degrees of rotation needed. No way that muzzle device will bottom.

https://precisionarmament.com/product/accu-washer-system/

image.png.704f545f7a8be9729b3eaff82ff0e9d0.png

image.png.6f4f335fe8d59db700fc24c5fc992486.png

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2 hours ago, 98Z5V said:

I use these, almost exclusively now. I don't even look at crush washers anymore, or peel washers.  These things are the sheeeeiiit.

With these things, you base it off the largest shim, and calculate from there - they include a chart, for degrees of rotation needed. No way that muzzle device will bottom.

https://precisionarmament.com/product/accu-washer-system/

image.png.704f545f7a8be9729b3eaff82ff0e9d0.png

image.png.6f4f335fe8d59db700fc24c5fc992486.png

I can use those on the the standard 51T's but I have several that have a deep socket that the Precision Armament washers won't fit in, wish they made a smaller O.D. set.  I end up using the couple thicker shims from an AAC or GemTech kit then have a pile of the thinner ones left over, anyone needs some of those extra thin shims let me know.

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19 hours ago, jtallen83 said:

Hope I get a chance to check accuracy and POI shift this trip home, I will report back when I do whenever it happens.

Groups moved about 1 inch low and right. Shot 4 groups of five this morning, accuracy was not up to snuff but I broke the bolt catch on the first shot and was tuning the new to this rifle SLR gas block so I lacked consistency this morning.

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3 minutes ago, jtallen83 said:

 accuracy was not up to snuff but I broke the bolt catch on the first shot

Damnit! 

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15 minutes ago, 98Z5V said:

Damnit! 

Added another quarter to Aero extension in hopes of causing less shock, 75 cents now and that is after cutting a notch as well. Catch had a bubble in the casting so I'm sure that didn't help.

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New Sig bolt catch is working great, accuracy was just crap, vertical spread was horrid. Suppose I need to give it a few more trips to be sure it wasn't just me this morning, wasn't hitting well with much of anything in 308. If it wasn't me then I guess I take out the shims and torque it back onto the shoulder.........

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On 8/7/2018 at 10:20 AM, jtallen83 said:

If it wasn't me then I guess I take out the shims and torque it back onto the shoulder.........

It had to have been piss poor shooting on my part. Shot 8 five round groups this morning and only one was over 1 MOA. Took my time and gave it a good five minutes to cool with the barrel cool fan running between groups. 

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What were you using for shims on the muzzle device?  Before?  Or now, really.  About a year ago, I got away from everything else, and I'm only using Precision Armament Accu-Washer index washers now, in 1/2" and 5/8".  Nothing else.  Those things are far superior to anything else out there for timing/aligning muzzle devices.  :thumbup:

I only buy them from Mounts Plus, because those guys never run out of stock.  Great Company.  :hail:

https://www.mountsplus.com/precision-armament-accu-washer-muzzle-device-alignment-system.html

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14 minutes ago, 98Z5V said:

What were you using for shims on the muzzle device?  Before?  Or now, really.  About a year ago, I got away from everything else, and I'm only using Precision Armament Accu-Washer index washers now, in 1/2" and 5/8".  Nothing else.  Those things are far superior to anything else out there for timing/aligning muzzle devices.  :thumbup:

I only buy them from Mounts Plus, because those guys never run out of stock.  Great Company.  :hail:

https://www.mountsplus.com/precision-armament-accu-washer-muzzle-device-alignment-system.html

The Precision washers won’t fit this particular device, it is a deep socket version, used Gemtech on this one. I have used the precision and really like them, always try them first!

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7 minutes ago, jtallen83 said:

The Precision washers won’t fit this particular device, it is a deep socket version, used Gemtech on this one. I have used the precision and really like them, always try them first!

Shiit. Some newer AAC brakes are like that, too.  I thought about putting the Accu-Washers in a lathe to turn down the OD, on one AAC BrakeOut...  I get it...

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Can’t complain, I have been picking up AAC 51T’s for $30-$50 on fleabay. Take what I can get at that price!

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