I just received a flier from Hastings announcing their "Open Field" model slug gun and their 3-1/2 inch 20 gauge custom slug ammunition. The ammunition is described as having a 350-grain soft lead slug with a 60 grain impact-discarding sabot. They claim a 2000 fps muzzle velocity and 3600 ft-lb energy. They also included a ballistics chart that shows a 140-yard zero with a maximum rise above the sight line of 2.46 inches. They claim a remaining velocity of 1161 fps at 200 yards. If this information is true, they just might have something here.

The "Open Field" gun appears to be a rechambered NEF break-action single shot with a heavy rifled shotgun barrel.

I'm going to send my NEF rifle action to NEF and have a heavy 20 gauge rifled shotgun barrel fitted to it and then have it rechambered, either by Hastings or by someone else, for the 3-1/2 inch cartridge. Then I'd like to try some of the ammo. They list a couple of my distributors as handling their products so I'll see if I can obtain some of the ammo. I'll report what I find. If anyone else has any experience with the ammo, I'm sure that the rest of us would like to hear about it.