Checking for concentric threads

Talk about them here.

Moderators: mpallett, bakerjw

Post Reply
User avatar
jwise
Silent Operator
Posts: 79
Joined: Wed Sep 20, 2006 12:04 pm
Location: Texas

Checking for concentric threads

Post by jwise » Mon Oct 20, 2014 10:29 pm

I have a recently acquired M85 which I want to suppress. I bought an adapter (I know, the 'A' word) to go from 26mm LH to 5/8x24. I would have gone all the way to 1/2x28, but they didn't have any available, and the 5/8x24 51T mount cost the same as a 1/2 x28 mount, so who cares?

I picked up the mount the other day, and the adapter came today.

Here is the adapter installed:

Image

And the 51T mount:

Image

And with the M4-2000:

Image

I checked the line up by looking down the bore (took the bolt out to do this), and then shining a flashlight down the chamber.

Here's a pic of the light coming out the muzzle:

Image

What other checks should I do before locktiting the adapter/mount?
J. Wise

User avatar
Bendersquint
Industry Professional
Posts: 11359
Joined: Sat Jan 07, 2006 9:19 pm
Location: North Carolina
Contact:

Re: Checking for concentric threads

Post by Bendersquint » Tue Oct 21, 2014 4:20 am

I would actually measure for concentricity, flashlights are not a valid means to verify concentricity.

User avatar
jwise
Silent Operator
Posts: 79
Joined: Wed Sep 20, 2006 12:04 pm
Location: Texas

Re: Checking for concentric threads

Post by jwise » Tue Oct 21, 2014 10:40 am

How does one "measure" for concentricity?

I plan to take this setup to my gunsmith to have him look at it, but I wanted to check as much as I could myself so I don't waste his time.
J. Wise

Post Reply