GL barrel threading?

[boostless]

I have a GL and recently plopped the money down for a silencer. If you know your rifles you'll know that this isn't threaded. Honestly I'd like to swap put the barrel for something heavier and threaded but I don't have the equipment to do it myself. Is there enough meat on the end of the barrel to thread? I wouldn't be opposed to shortening the barrel either.

[J.Baker]

Not sure what the muzzle diameter is on those barrels, but this may be of some help in finding the answers you're looking for.

http://www.advanced-armament.com/assets/images/pdf/manuals/ThreadGuideREV_01-040513.PDF

[boostless]

Seems like a good bit of info there, gotta get on my computer to see it clearly