On this forum there are reports that a Nikon Apo-Nikkor 305mm is a straight fit in standard shutter (No.1 IIRC).
That's not true, or at least it's not true for my example, which is the common one, and probably the only one ever produced.
There should be a 300mm one, of older design, but no other 305mm, AFAIK.
To give a more usable information, i am attaching a picture of my lens.
I must admit that i purchased the lens with the plan to fit it in one of my "orphaned" shutters, but i stopped before dismantling the whole lens, once i found that the front glasses are not enclosed in a cell. If you open the front of the lens you end up with a bunch of loose parts, practically impossible to be fitted in a shutter, without incurring in unreasonable expenses (you can find a nice, recent Apo-Ronar for less!).
I didn't remove the set screw at the back of the lens, cause there was no need to investigate any further...
If you found the same infos, and thought to buy an example to fit it in shutter, please make no mistake.
I decided to come forward to spare others the same mistake i made