I too have thought about using the bird cage flash hider and JB welding a washer on the end of it and soldering the now "muzzle brake-(via the washer)" on the the barrel for a permanent muzzle break. This will give my A2 the look of the original flash hider (cuz it is the original turned into a muzzle brake). EGW (www.egw-guns.com/egw.htm under "parts") sells the same one for $50 as well as brownells (product number 296-201-017, www.brownells.com).
I can't help but to think that they are using the original A2 bird cage and fixing a washer on the end and marking up the price $40, though I could be wrong and would like to be corrected if someone knows some facts about the product. Or more specifically of why the BTAF considers EGW's brake a true brake and why my "homemade" brake would not be.
Cleatus, as for if pinning alone is ok I’m not sure (my opinion is that it is not permanent if it is just pinned, but I’m not 100%). I have also “heard” that welding it a minimum of half way around the brake is good enough for it to be considered permanent. And lastly that if it is soldered on it is considered permanent (get 1100 degree silver solder paste, clean the brake and barrel free of oil (use acetone, metal MUST be clean), smear the paste around the threads, thread the brake on and off a few times to assure the paste is in covering the threads, and heat with a MAPP torch until a dull red (1100 degrees) or until you see the paste turning to a wet appearance, oil after cooled to replace the oil that the acetone took away). I just soldered a brake on to my FAL last week.
If anyone can throw in their 2c on the subject I would like to know more of what is ok and what is not. Any feed back is appreciated.