Best Nail Guns For Crown Molding - Millwork Guide- finish nail length for trim ,1/10/2018· Best Nail Guns For Crown Molding. Hitachi NT65MA4 1-1/4 Inch to 2-1/2 Inch 15 Gauge Angled Finish Nailer with Air Duster. Pros: Cons: BOSTITCH N62FNK-2 15 Gauge 1-1/4 Inch to 2-1/2 Inch Angled Finish Nailer. Pros: Cons: Senco 4G0001N FinishPro 42 XP 15-Gauge 1-1/4 to 2-1/2 Inch Finish Nailer with Case. Pros:Attaching Interior Trim Securely | HomeTips23/11/2020· Because trim boards are often thin and narrow, they must be anchored firmly or they could pull away from the wall or joints between trim pieces could develop noticeable gaps. Finding Wall Studs In most cases, trim should attach to wall studs, which are usually (but not always) spaced every 16 inches on center, meaning the center of one stud is 16 inches away from the center of the next stud.