Charles Lancaster
An Illustrated Treatise on the Art of Shootinghttps://books.google.com/books?id=O2GzwW9tKCoC&pg=PA15&vq The author has invented an adjustable try-gun (patent), which is constructed with the stock perfectly rigid in the hand, being made to move in right lines (and not bodily, by the means of a knucklejoint in the hand of stock, which necessarily describes the section of a circle), therefore the author's does not give an excess of bend or cast-off, yet it can be adjusted for cast-off, bend, and length, also for set of toe or heel of stock, so as to be correctly adjusted to what is required for any individual sportsman, to enable him to make accurate practice when firing at either targets or game ; or the author's original adjustable gun (with specially constructed fittings) can be handled to demonstrate that the measurements taken by him are correct as to bend, length, and cast-off, thereby showing that the gun to be supplied will be suited to the purchaser.
Greener
https://books.google.com/books?id=InYSAQAAMAAJ&pg=PA405&dq Jack Fanning, the A.P. Curtis try gun, gun fitting and shooting style
Recreation, December 1914, “Your Shotgun Affinity”
https://books.google.com/books?id=DYA7AQAAMAAJ&pg=RA1-PA323&lpg https://books.google.com/books?id=DYA7AQAAMAAJ&pg=RA1-PA347&lpgParker 1915
https://books.google.com/books?id=EpcwAQAAMAAJ&pg=PA257&lpg 
