Very easy to Mount on a .17cal to .22 Rimfire Rifles all the way up to a 12 gauge Shotgun's. This Light is very well made and comes with the custom mounts for attaching to barrel or on Tubular Magazine, as I have mine attached to my Remington model 11-87 12guage for Home defense, and I love the way the light comes with the curly cord or optional flat base with standard push button on off. I personally like the Curly cord but you never know and especially if you want constant I like the options. Also the mounts won't harm you firearms finish as the mounts have nice rubber molds to keep from scratching surfaces etc as well as the Light. I love my new TacStat light and it's also a big plus that the light runs on 2 AAA batteries that were included. Also this Light is very Bright I feel it's pushing out around 100 to 125lumens instead of the advertised 75lumen output which is another Bonus. Thank you Impact for a Great Light for a Great Cost! Highly Recommended if looking for a long gun light but on a bit of a Budget!