FWIW: 'Baltimoreed' - I took the liberty of copying your 'Constabulary' Rifle picture and marking the location, that should measure approximately 9/16 of an inch.

(In photographs of two Krag actions, up-close and side by side, the camera angle distorts appearances and makes comparison difficult. I can't trust my eyes and have to measure).

Your model 1899 ('Constabulary') might have a model 1896 follower-arm assembly, that doesn't quite fold and retract, like an 1898/99 one. (?)

There is a flange on the bottom of the magazine-gate that touches the lower receiver and limits the travel of the gate. So, unless metal has been removed, gate travel is 'fixed'.

(BTW -There is just the one spring that powers the follower-arm assembly and tensions the magazine-gate).

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