OK, Lloyd, the average breech wall thickness on my 1899 NIG (the one I referred to as a fraternal twin to yours and an example of the “double thick Nitro breech”) is .232”. By comparison, my 1901 NIG’s average breech measurement is .169”. Both have twist barrels and both are 16’s.

For further comparison my 1900 16ga Crass is very close to the ‘01 NIG at .166”.

An early 16ga Lewis of this same period averages .182”

And right after it, an early 16ga Minier was in the same range averaging .178”.

For reference: a 1891 16ga NIG comes in at .187”.

So some speculations:
The “double thick” guns were noticeably thicker but far from “double” thus this was a marketing slogan rather than a statement of fact.
During this brief period of a few years, the standard weight NIG’s and Crass’ were essentially the same in breech dimensions while Ithaca tried to alleviate the Nitro fears of a segment of their potential customer base.
And after the Nitro “concern” lessened, Ithaca decided to return to earlier breech wall thicknesses of around .180” perhaps to reassure buyers.

Admittedly, these speculations are based on a very small sample. Hopefully, some of our compadres here can add measurements of their guns from these years to increase our understanding of this interesting period of Ithaca guns.

Last edited by FallCreekFan; 04/22/25 07:19 PM.
Speude Bradeos