A man from Caribou is going to prison for more than six years for selling marijuana and illegally possessing guns. 32-year-old William Quirion was sentenced Tuesday in federal court in Bangor. He pleaded guilty last summer.Almost two years ago, authorities found nearly 10-pounds of pot in Quirion’s house and four firearms.He’d previously been convicted of a felony and wasn’t allowed to have weapons. Quiron’s girlfriend, 41-year-old Sherri Mancos, has also been charged in the case. She’s scheduled to go on trial next month.