I believe correct usage is important too, as long as we don't get to the point of "political correctness" with it. That happens too much already. For example, in the old days, the term "knockdown power" was often used when talking about a bullet's effectiveness. Then all of a sudden the term was scoffed at because a bullet doesn't have the power to "knock anything down", and the term became "stopping power" even though, hypocritically, a bullet doesn't have the power to "stop" anything either. Now if you use either term you get flamed, when all both terms just mean effectiveness. Another example of us pushing our own political correctness is "accidental discharge". Say that and you'll get flamed and told there's no such thing, that it's a "negligent discharge." While I agree that negligence is the cause, the word accidental fits just fine, as it means that the discharge wasn't done deliberately. Just like a traffic "accident" is almost always caused by negligence too, but nobody gets bent out of shape for it being called an accident.
I do have a couple pet peeves. First off, it's muzzle brake, not muzzle break. Secondly, this one is my biggest pet peeve, because the people who do it the most are the ones who should know better the most. Varmint has an N. It's not spelled varmit. The biggest offenders here are the varmint hunters who have probably seen it spelled correctly thousands of times in ads, magazines, on loaded ammo, loose bullets, optics and in discussions with fellow varmint hunters.
I guess these minor pet peeves really aren't related to correct usage, but hey, it was a good place to vent!