Today I am out at the range with Matt Haught of Symtac Consulting to test out a duckbill choke. Also known as a spreader, this was a muzzle device used briefly by SEALs in Vietnam – the idea is to spread shot in a horizontal oval pattern instead of a circular pattern. This improves the likelihood of hitting a hidden or moving target at ground level. The original devices were not all that well made, and tended to crack and widen under the repeating impact of use. The one I have today is a hardened reproduction made by Chuck Madurski and Kevin Dockery many years ago. It was fitted to a Remington Model 11 barrel for me by Vang Comp (who also installed the extended magazine and handguard). Matt and I are going to try out three sizes of buckshot; #00, #1, and #4 at 10 yards to see if the duckbill actually does what people claim.
What we found was that the device works best with #4 shot, with marginal effectiveness using #1 and no effect with #00. We saw a shot pattern of rough 3:1 width to height, with the height being approximately equal to the diameter of a plain cylinder bore gun used as a control. At 25 yards, this resulted in a pattern more than 3 feet wide, hitting multiple side-by-side silhouettes.