Here's that strange screw

Do serial #'s match (?), since the fore arm has a metal tip which are found on earlier serial # Hepburns.

Does the end of the set screw rub against the side of the hammer?  Do you see any rub marks there?

It looks aftermarket to me.  Since the .30-40 was a higher intensity cartridge than most chambered in the Hepburn, perhaps the owner found that although the action would hold up to any reasonable loadings, the rebound feature would allow the primer to flow back into the firing pin hole, making the action hard to flick open with the side lever.

This situation happens sometimes with my 40-90-3-1/4” Hepburn, requiring a second snap to drive the primer back so I can open the action.

Frank deHaas recommended grinding the rebound feature off the Hepburn main spring and manually setting it to half cock if the action was to be used in a varmint rifle.  This would keep the full force of the spring and hammer pressing the firing pin forward, keeping the primer flow to a minimum.  This always seemed to me to be kind of a shame, since the rebound works so nicely.  Maybe a previous owner figured that a judicious amount of drag on the side of the hammer would retard the rebound until the chamber pressure dropped.  He would then have the best of both worlds.

Just a guess, but if you shoot the rifle with factory loads and tweak the screw a little as you shoot, you may be able to see a difference in the primer dents.

That is a fantastic specimen.

I have a Match Grade A 30/40  with double set triggers. The barrel is only 30".
Kurt

Color casehardening will tell you if screw holes are factory or not. If the colors are in good shape you can see the patterns that swirl around existing screw holes. If there's no pattern around a hole, it was likely not there when the action was quenched, and the colors developed.
Notice how all the other holes have the pattern around them?

Does yours have that big old wide front dovetail? I think they're around .450" or so? Mine is missing it's windage front globe, and has a later non windage globe on it. I keep threatening to just order an MVA to put there, so it at least has a windage globe.

Spud wrote on Mar 20^th, 2019 at 8:54pm:


Yes, especially when they're oddball dovetail sizes like Remington and Stevens used! If they were the more common .375" size there'd be a chance of finding them, and not paying more than a good gun costs! 
I've seen a lot of windage adjustable globe sights with .375" dovetail, but almost none loose from guns with the wide dovetail.

If a reproduction will satisfy you. You might check out gunparts. They have most of the parts to build a Mid-range rear & a windguage front sight.
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spud,i have been reluctant to post this anywhere yet but it is getting out.i have bought axtell sight co from carmen axtell.i am in the process of tooling up and reintroducing the sights to the gunworld.right now i have some shortrange ,midrange and longrange remington vernier tang sights available.i will be in tulsa, denver and the quigley shoot in montana. with what i have available .this is a slow process because carmen did not have any of the tooling ,so i am having to make everything.contact me if you want a midrange for your gun.      tony <><

SSrifles, thanks for your post, that's very interesting news and I'm sure many will welcome the return of quality, traditional style sights. Good luck with your endeavor. PM sent.
Spud

I had Distant Thunder make me some apertures for the Numrich Remington sight. They took some minor fitting but work fine. it also allowed me to pick the aperture ring diameter.      
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Kurt