Muzzle Threads

[ssapach]

Simple question, it might even sound like a stupid question to some, but is there a list of common threads used for muzzle attachments? Or is that all dependent on manufacturers of attachments and who does the barrel threading?

I can't imagine everyone who makes attachments uses whatever threads they feel like, just to be unique with their own products.

I'm also curious about threads used based on calibres. If a certain size is used for .22 cal barrels, how large of a calibre does that particular thread get used for or is there a size change over after a certain calibre?

 

[tiriaq]

There are some sizes commonly used. 1/2-28 is the common AR size. 9mm ARs use 1/2-36, iirc. 5/8-24 is common, as is 3/4-16. You will see the occasional 9/16.
The threaded diameter needs to be in proportion to the caliber, and often to the barrel diameter. It is usually desirable to have a shoulder for the brake to butt against. 1/2-28 is about as small as you will see with .30 caliber. This is commonly used when a M305 barrel is shortened and threaded.
Then there are the metrics.

 

[EHG]

I have one brake that is 5/8" x 32 TPI. I not sure who made it, but it came with a barrel I bought years ago.

 

[Leeper]

There is no standard though there probably should be. Just like lug nut patterns on wheels, it seems to be at the whim of the maker. I am no different in this respect. I choose a thead diameter and pitch according to what I think should work well.

 

[ssapach]

Thanks for the input guys. My internet snooping seems to suggest that 1/2-28 is the most common used for the .22 cal stuff, which is what I'm after most immediately. Might tinker with some larger stuff later, so it's always good to know that as well.

I really didn't expect that it would be all over the board though, I sort of hoped there was some standard threads to use that just about everyone already used.