How much thread on VGS Jeff's 18.5" Vortex?

[Steiner]

I won't have access to my chopped M305 rifle for about 4 weeks. Can someone tell me how much thread is on the end of the 18.5" barrel when Jeff mounts the Vortex? I'm getting one of these 9 port muzzle brakes:
http://brakes.ricksmuzzlebrakesandgunstuff.com/index.htm and the fellow wants to know how deep the the 9/16x28 thread needs to be cut into the brake.

Also, can someone verify Jeff does use 9/16x28 thread? I did read this somewhere but but I want to verify and be 100% sure. I tried many times to call Jeff at VGS but no luck and time is running out for me.
Thanks guys.

 

[Shazam]

Why not ask Jeff?

He"s a great GS. Top Notch work.

 

[Steiner]

I tried many times to call Jeff at VGS but no luck and time is running out for me.
Thanks guys.

Yes, he's a great GS. Did a wonderful job on the M305.
I've tried to contact him numerous times but no luck.

 

[Shazam]

Yeah they dont answer much (probably busy making the best M305 / M14S carbines out there).

Try dropping him an email

 

[Craftsman 441]

Jeff cuts a 1/2"-28 thread and drills-out the FH from .22 cal to .30 cal.

 

[weebull]

Yes, he's a great GS. Did a wonderful job on the M305.
I've tried to contact him numerous times but no luck.

Ya Jeff's the greatest. Is it VGS or valley taxtical. smiths tactical, or what now

 

[RePete]

VGS or Valley Gunsmithing.

 

[Steiner]

Yeah they dont answer much (probably busy making the best M305 / M14S carbines out there).

Try dropping him an email

I tried email also. Guess he's just too busy churning out M305 shorties.

 

[Steiner]

Shazam - thanks for prompting me to email Jeff one more time. I got a reply this time.

Here is Jeff's comments:

The thread is ½” 28 , the same as for AR-15 flash hiders, so you will be able to use various flash hiders that are threaded for the AR-15.

IMPORTANT: the flash hider must be bored out to accommodate the .30 cal bullet diameter, a rule of thumb is no less than 20,000 over the bullet diameter.

If you can drop a bullet through the flash hider with out the edges touching after it has been bored out, you are ok to put it on.

I think I'm going to try the Smith Enterprise muzzle brake:
http://www.smithenterprise.com/spec/5.56mm_Muzzle_Brake.pdf

I might even try an AK74 brake on for a comparison:
http://www.shop.preciseinnovationsllc.com/category.sc?categoryId=6

I'll post up results after I try them out.