Stillman Taylor, Popular Mechanics, November 1915
https://books.google.com/books?id=td8DAAAAMBAJ&pg=PA784&lpg

Obviously not a Vic Venters quality study, but interesting.

Can anyone ID the maker? A 2 piece mainspring with a roller-bearing.



Tobin used a roller-bearing on the short arm of the mainspring





An illustration of what appears to be the Alexander Brown "Double Cross Bolted Treble Wedge Rib Extension", with an odd non-Smith lump. Did another U.S. maker use the rotary bolt?

Found it.
Hardware Dealers' Magazine June, 1914
https://books.google.com/books?id=tpY7AQAAMAAJ&pg=PA1366&lpg



https://www.gunsamerica.com/934593895/Rare-Stevens-Model-345-20-Gauge-Sportman-s-Idea-Sx.htm

Fox also used a "rotary bolt" linked to the top lever.



Ithaca Flues used an extension off of the top lever and an underbolt

Stevens 311, 315 & 330 top lever with a hook that engaged the top rib extension

Crescent hammerless used a similar lock-up plus an under-bolt.

The Ithaca Lightning Lock was part of the Flues marketing
https://books.google.com/books?id=yR4AAAAAMAAJ&pg=PA53&lpg
The illustration however shows the early NID cocking indicators. Did the NID have a rotary bolt?

Drew, yes the NID joined the Smith and Fox with a rotary bolt. Smith did the best job fitting them. Capt. Askins and Elmer Keith both had issues with Fox and Ithaca guns popping open, no mention of it happening with Smith guns.