You could be right, but I've looked down machine gun barrels that looked pretty crisp after a lot of 4B/1T.
Given that even armies have to live with budgets and given that barrels are expensive, I would also suggest that if tracers were indeed destructive, there would be some serious pressure on ammo manufacturers to come up with a non-destructive tracer composition. They've been at it since WW1,after all.
Moreover, more and more tracer ammo has a delay element, meaning that the tracer does not ignite until it's a ways downrange, making it harder for the enemy to locate the firer. It would also mean that the main fill would not be burning inside the barrel.
I would suggest that you're safe.
BTW, most machine guns, especially if mounted on a tripod or a proper vehicle mount, are very accurate. Carlos Hathcock used a scope on a .50 as a long-range (2 km +) sniper weapon in Vietnam. The myth that machine guns just spray bullets around is akin to that suggesting the same for shotguns.