John
I believe we can still possibly get 2" 410's here which would equate to the 'shorts' for this shell - might have to wait, but seems getting them is possible.
https://www.horsleyparkgunshop.com.au/category/379-410-gauge

My old H&R Model 1915 has "410-12mm choke" marked on barrel, so it was made approx 1922-36 so its getting up towards a century now; & it has the 2 1/2" chambers.
I'm not 100% certain here but I believe the 2" shell differed only due to a smaller payload.
The 3" shell came out around 1927, so it is possible it could even be a 3" chambering - if so then it will be of stronger steel & hence a lot strong than my ol' snake charmer!
Is it tight on the face, yes it is; but is not shot a great deal & loads are kept exactly within know parameters to avoid overloading.
A bit more reading on the humble 410 if you are interested
https://cartridgecollectors.org/?page=collecting-410-shotshells