full choke
To the author's surprise, a Full choke and steel BB turned in terriffic patterns. John Hafner

Full chokes and steel shot don’t mix, except when they do. Full and steel damage barrels, except when they don’t. Full chokes and steel produce blown patterns, except when they don’t. Full chokes and big pellets – BBB and T – really don’t mix, except when they do. Figuring out where the truth lies is difficult. Here it is. Most of it, anyway.

Inspired by my own possibly premature statement that shotgun slugs are nearly extinct, I traded my H&R Ultra Slug Hunter in on an older 10-gauge BPS. It’s in good shape, but came only with the Full choke tube screwed into its barrel. Rather than wait for the IC and Modified chokes I ordered for it to arrive, I ran out to the range to pattern it anyway, because I was excited about my new gun, and because I’ve seen some 12 gauges shoot good patterns with smaller (2) steel shot and Full. The gun shot terrific tight patterns with 1 5/8 ounces of BBs. It would kill a Canada goose at 50 yards if I wanted to shoot one that far away.

The big bore of a 10 gauge is renowned for handling large pellets well, so I wondered if maybe this was just a 10 gauge thing. I decided to push my luck and shoot some BBBs out of a 12 to see what would happen. In theory, my Full choke 870 SuperMag should have produced patterns with donut holes in the middle. In fact, it shot 70% patterns at 40 yards with Winchester DryLok BBBs. That’s okay, not great, pattern performance, but it was good enough to work in the field. Perhaps a different choke would yield better patterns, but there wasn’t a donut hole in sight.

So, does steel pattern badly with Full chokes? Not necessarily, although your mileage may vary.

I have only fooled around with Full chokes and steel on the pattern board, so I can’t tell you what happens after hundreds or thousands of rounds of steel through a Full choke. I called someone who does know: Rob Roberts of Rob Roberts Gunworks. Roberts said for the most part, you can shoot 3 and 4 steel through a Full choke with no problem. Big shot, however, can be a different story with Full choke, at least in extreme cases.

“We get six to eight guns a year where we see some swelling behind the choke,” says Roberts. “Now these are guns that have been a shot a lot, probably by guys who don’t clean them much, for five or six years.”

In some instances, those guns wind up launching a choke tube into the water. When the tube sails, the threads are ruined. Roberts fixes the problem using industrial strength thread locker to put a choke tube permanently into place.

The question is less “can you use Full choke and steel?” than “should you use Full choke and steel?”

Steel does pattern more tightly than lead, and most waterfowlers, with the exception of a few skilled pass shooters, are overchoked anyway for birds hanging over the decoys.