There is considerable historic literature on the big bores, both shoulder and boat-mount fired. Snowden Slights and other names are worth reading up on. A few modern guys have written some reports on the over-Ten guns, but for reasons of attracting undue attention, they remain unpublished
One of the long time scholars of this bit of waterfowling's past is Jim Marsh, on the shallow Western End of Lake Erie, on Michigan's Eastern shore. In it's day, that arc from Lake St Clair above Detroit, around to the east end of the Sandusky Bay on the north shore of Ohio was as rich a resource as any other more famous shooting grounds.
In fact, one of the most exclusive and little known duck clubs in the world still exists on those wetlands, unchanged, with it's very limited membership of senators, presidents, and captains of industry. They used Chesapeake Bay Retrievers from the club's kennels, in the day. Today, I believe the puntmen bring their own dogs.
For many years, since mebbe 1982?, Jim Marsh would fire off his puntgun twice a day at the fall Pte Mouilee Waterfowler's Festival, north of Monroe, Mi. He is also the keeper of many of the extinct private club records, an expert on the local decoy carvers and historic hunters, has and restores all sorts of the marsh and bay craft.
He did a punt gun demonstration similar to the one seen in the U-tube videos, several years ago at Midwest Double-gun event, over near Cleveland -- some sporting clays club with ponds. The balloon slaughter was a tho a giant lawn mower had passed in an instant thru the 'flock.'
On that same misty and wet summer day he had an exhibit of big guns, including four gauges. The 4ga paper shells got swollen in the damp. So the shoulder firing of fours, as a cleanup to the Punt-load didn't go as planned. Some modern Tens, had to suffice; one doubled and gave a fella named Bret ;~`) a hearty shove.
After some foolin' about, the cartridge Four did get touched off later, and I think Jim had a picture of the gun in full recoil. It had express sight for fifty and one-hundred yards. BTW, the recoil is tolerable, but I'd say that I wouldn't want to fire it more than four or so times a day. Heavier than a .500 Nitro double, but not as sharp.
Some years ago at the annual decoy [and everything else fowl] show over in Lakeside, Ohio, west of Cleveland, I just missed a lovely 4 gauge percussion that appeared quite shootable. It was very well thought out and obviously designed for shoulder use. The bbl was only mebbe 26" long -- eight-sided from the patent [!!!] breech, to sixteen facets, to wedding ring, to round -- which gives a good weight distribution. The half stock was straight and tight grained elm, and it had a backlock action -- minimal wood removal, there. Can't remember if it had a loading rod, or not. The gun was very handy, swung well, was in good shootable condition and had sold for $450.00. Sob.
If Jim will show up here, I'm sure that he'd be a valuable resource to these sorts of discussions, as he is true treasure house of firsthand knowledge on this particular subject.
