We equiped a Mossberg stainless steel mariner 12 gauge shotgun with a 35 Mw green laser. This laser is so powerful you can see it in bright daylight. Then we loaded our laser shotgun with 3" rifled slugs. Now we have an 8 shot laser guided canon that shoots a 1.25oz lead round 2400fps. Thats just about 20mm, and its accurate up to 100 yards. Check