40mm with a 1/7" thread pitch
Aside: I hope this 1/7" is something sensible in metric.
Thanks for the tip. It seems like this should exist, just like 3M makes (eg) 501 filter retainers for filters like this.
But I guess there's none for NATO 40mm.
How about a 40mm to bayonet adapter plus something like this?
edit: this looks like it might be a 3d printing job. 3d printing plan sites already have plans for various adapters, like this
Is this what you mean?
https://www.amazon.com/3M-Black-Orange-Filter-Adapter/dp/B004RH1RXG