I NEVER fire a new gun without taking apart, cleaning it, and lubing it.
Not long ago I saw a guy at the shooting range with a rifle to which he had gotten a muzzle break professionally installed. By sheer luck, he couldn't get his first round to chamber, so he pulled the bolt and inspected it. The "pro" who did the muzzle break job never cleaned the metal shavings from threading the barrel out of the inside of the barrel! Had one of those shavings not fallen into the breach, there could have been a serious Kaboom!