Hevishot Waterfowl Mossberg 12 Gauge Mid-Range 17-4 Stainless Steel Black In addition to world-class ammunition, Hevi-Shot offers the best chokes for your hunt, with gun specific styles available for most gun models. The chokes are manufactured from aircraft-quality 17-4 stainless steel and utilize state of the art patterning equipment, to achieved the optimum constriction by gun type, for the best possible pattern. Each Hevi-Choke has a knurled fore-end and can be hand tightened for easy field change-outs.