dry brisket

Hello y'all! So I'm struggling with 7 lb briskets. still coming out dry; left fat on, did 250 deg smokes for 5- 6 hours, reaching 190 deg internal in the flat. they look great but still a bit tough and dry. i figure they need more time, but reaching 190 degrees so ? advice please Thanks !

Howdy all, just fired up my new WSM 18". did a chicken to warm it up, worked great. Cooked a 7lb brisket yesterday: minion method charcoal, mesquite wood chunks, water bowl 3/4 full, held 235 - 250 deg cook, after 6 hrs internal temp was 165 and stalled. I have to admit I went for the Texas...