We did a bunch of testing with a variety of anti-seize compounds many years back. The idea at the time was to see if we could come up with something to prevent crap from sticking to the baffles. So for some of these tests we coated the inside of the blast chamber and the rear faces of all the baffles with nickel high temp, copper or graphite anti-seize and blasted away. What we found was that it didn't make much difference in the rifle cal stuff as it all got blasted away after a few shots. No carbon build up was ever seen and we never melted any of the anti-seize. In the 22LR cal cans it actually seemed to help a bit unless you went too long between cleanings. About 500-1000rds seemed to be ok. Stuff scraped off better than without anything but it was still messy and anti-seize isn't cheap. In the 22LR cans there was no evidence of any more carbon buildup than without anti-seize. So the BS meter is usually pegged when I hear that running anti-seize on the barrel threads has gummed up a suppressor. It just doesn't make any sense to me after goobing the crap out of them and seeing no issues to have a micro tiny amount suddenly create chaos. In addition to that we've done a number of endurance tests with belt feds and high powered stuff to see how the cans react to high temps.....the answer is not so well if its too hot. Despite overheating things we still never saw any difference in buildup between running and not running anti-seize. We normally run the high temp nickel because the graphite is really intended for other purposes and copper is something we never used around aircraft when I was working on them so nickle is what's left.
One detail about anti-seize. The grease used is a carrier, not the material that does the work. It is used to keep the actual anti-seize in suspension so that it can be applied. The reason parts seize up is called galling. It is a process by which metal parts weld themselves together in spots and with threads this really screws things up.....or should I say that it locks it up. Usually dissimilar metals won't gall together so running stainless can on a chromemoly barrel will be ok and vice versa. There are some materials more prone to this than others as well. Titanium galls on everything. Its really bad. Some stainless can gall on a wide range of things too. What normally leads to this is the carbon crap scraping away the surface of the threads exposing nice clean metal that will weld to the metal on the opposite parts threads where it has been scraped clean. What the anti-sieze actually does is deposit microscopic flakes of some other metal or graphite on the surfaces and this will help prevent the welding. Even after the grease has been burned away the anti-seize still works fine because its the nickel, copper or graphite that is doing the work. Just a dab ul do ya.
I find carbon buildup on the muzzle face of my barrels after shooting for a while though the actual bore and exit are always clear. The carbon buildup is concentric and I've not seen any change in accuracy with the buildup. For the last 22 years or so I've been shooting suppressed and building suppressors so I have some real world experience.
Last thing I want to add is that the manufacturers aren't making their materials from scratch. They buy tubing and bar from a supplier. Each of these materials is made in a way that always has a possibility of flaws that can't readily be detected. Inclusions in the steel or titanium can be as bad or worse then engraving or nicks or scratches. If you have a flaw and engrave over the top of it you end up with a failure at some pressure lower than what the can should handle if it were flawless. These things happen and most manufacturers will take care of it unless you're a real trouble maker. Help them help you out and let them do their jobs. They need to know if there is something wrong as it will help down the road for everyone.
Frank
www.snipershide.com 
