Its not the lacquer gumming up in a hot chamber, its because the steel cases don't expand and seal the chamber as good as brass does. Also I believe most of the manufactures of steel cased ammo have given up on the lacquer and gone to a poly type of coating. I don't think it will hurt a gun, I shoot a lot of it in .223.I've run small quantities of Barnaul through mine with no issues, other than the mediocre accuracy. I have heard of the lacquer gumming up in a hot chamber after long strings of rapid fire, causing extraction issues. Never experienced it myself.
Jason
Its not the lacquer gumming up in a hot chamber, its because the steel cases don't expand and seal the chamber as good as brass does.
How would a poorly expanding case get stuck?
Jason
Because they don't expand and seal the chamber so it gets carbon fouled.