BATON ROUGE — Louisiana's annual Second Amendment Weekend sales tax holiday is currently underway.The three-day event exempts purchases of specified firearms, ammunition and hunting supplies from state and local sales taxes."So it's nice that they get a knowledge and we get a break. Normally, guns are always on a bad thing. This is always a good thing," Jim McClain, owner of Jim's Firearms said. "So it allows people to come in, save some money i…