1841 mississippi rifle

This is probably the wrong place to ask but maybe someone can point me to another forum where I may be able to get help. Anyway I have an 1841 Mississippi rifle made by E Whitney in 1850. For the last couple of years it has been hanging on my wall. Because I'm getting rid of my collection I took it down to list on gun broker. To my shock when you pull the trigger when it is half cock the hammer drops. Does anyone know what the cause would be? and if it is an easy fix . and if it is not an easy fix does anyone know of a gun smith that is good with antique arms hopefully in the Nebraska Iowa area thanks

Take the lock out and make sure the sear is engaging the half cock bent or notch. Check to make sure the sear moves freely and sear spring is in good shape and isn't broken. Oil the lock. Please post pictures of inside of lock. Look for rust since its been above the fireplace

Here are pics of the lock I sprayed it down with WD40 and I am letting it soak . It hangs above the fire place but we do not use the fireplace

I'm thinking someone has altered the safe notch on the half cock. It can be removed with a little work, it can also be redone if there's enough material. Your picture doesn't have the light shining the right direction to see clearly.

Can you take a picture at full cock so we can see the half cock notch.

here are more pics tried to do it with more light

Yes, someone has taken the half cock notch off. They made it look and act like the normal sear for some reason known only to them.

could a good gun smith refile this sear or would it have to be replaced

I would leave it, it's an antique and the new owner is going to hang it on the wall like you did. If you file a new notch, it will change the geometry of the tumbler and the sear will go into half cock every time you pull the trigger. It looks like the original tumbler too. You can get original and repro parts, but they will need to be hand fitted. A broken half cock notch is not that uncommon for some reason. It shouldn't actually effect the value of the rifle, it's a very nice rifle, indeed.

yes I guess I have 2 options I take a take a loss and price it on gunbroker for less then I paid for years ago and disclose the half cock problem. I already had listed at what I paid for i2Kt and it is way below the other 1841s on G B. or keep it for the wall and sell my 1842 Harpers ferry. trouble with that is I promised my wife I would get rid of all of my most expensive guns and the 1841 is more pricey then the .1842.