Lasers for 10 Ga chambers can't be found--I've looked everywhere. BUT if you can cut down a 10 Ga hull and slide a 12 gauge chamber laser into it--it works great! I've used this for scopes, red dots and Williams fire sights on autos and single barrels 10s. Use the laser first at 10 yds to get coarse alignment and then at 30 for fine tuning--you'll be fine at 40. Just check your patterns and tweak if necessary with a very tight choke. You will need a cloudy day or early morning but it's worth it. Just like using a chamber laser on a rifle, saves ammo and the shoulder!
