How could he not with that name?
Mueller leveled a semiautomatic .410-bore shotgun
That is possible, but I doubt it. Those are extremely rare. Even .410 doubles are rare. This smacks of a journalist trying to add a little glamor to his story.
From another site...
“THE SAIGA 410 IS AN AUTOLOADING SHOTGUN”
The Remington 1100 and 11-48 have been made in .410. A number of pumps, Browning BPS, Remington 870, Mossberg 500 and Winchester 42 exist. The doubles, both O/U and SxS are very numerous.
It’s a great gauge, I routinely break 90+ with it at Skeet.