Barrel key loose?

Im using a nice hawken style flintlock with two barrel keys. After a few shots i often see the rear barrel key has backed out slightly. Does this indicate a problem like the barrel moving in the stock, or is it nothing to worry about.

IMO, it's a fairly common problem and nothing much to worry about.
If I had to guess I would say the slot for the rear key is slightly higher than the other one or, the slot thru the rear underlug is slightly lower.

With the idea that the slot is slightly too low, you can improve things if you remove the barrel from the stock. Then, putting a key thru the rear slot, use a small hammer to lightly tap the bottom of the underlug. The idea here is to slightly move the metal under the slot towards the key. The reason for putting the key in the slot before tapping on the underlug is to keep the underlug from bending too far.

It doesn't take very much bending on the underlug to make a large difference in how the keys fit so if you try this, go easy. It's better to bend it too little than too much. After tapping the underlug, reassemble the barrel into the stock and check on the key's fit. If it is still loose enough to allow you to move it with your fingers, more adjusting to the underlug will be needed.

Some people think that bending the key is a good way to go. It doesn't take much to bend the key but using this method you will need to be careful to always use the same rear key, installed with the same side up to get a snug fit. If the key is put in upside down it will literally fall out of the slot from its own weight.

It just means the hole that the key is in is too big.

The keys provide very little structural support. They are only there to hold it together. Where the breach meets the stock is where the energy is.

Several ways to solve the problem depending on the severity.

If its just slightly too big, rub some bee's wax on the key. works but must be reapplied occasionally.

Or, peen or bend the key a little until it goes in more snug. Easy Peasy!

Good Luck!!

Zoni beat me to it!!

And his advice seams better too!! Makes sense to me. Learn something every day!

I had a wedge that insisted on coming out of my CVA Mountain Pistol. I decided to make use of the slot in the wedge to capture the wedge. The pin can be placed under the escutcheon or in the stock as I show.

It can be a bit of a pin to remove the pin, but there is still a bit of the head of the finishing nail to get a hold to remove it. That doesn't happen often.

My keys are captured so i wont lose them. I was just wondering if a loose one is a very serious problem. I will tighten it up a bit i guess.

I just bend the key very slightly until it fits tight and sure. Doesnt take much memory to remember to place the key in with the bend down. I wouldnt bend the barrel lug, personally. If you have two keys just stamp a dimple in the rear one to remember.

I bet you don't have the same issue in February that you do in August. Very likely your experience is a function of seasonal wood movement. Not much you can do about that. I have the same thing going on. In February I can barely get the gun back together. In August it almost falls apart, and I have to check my keys all the time to make sure they stay "home" and keep them in.

Yes, as Zonie said you CAN tighten up the bottom of the key slot, but this may cause you trouble come the drier months of the year, and you may not be able to get it back together.

I solved for some of this by lightly coating the tops of my keys with rubber cement, as well as the barrel bottom they ride against. This gives me just a little bit more friction to keep them together. In the winter time it can easily be removed if need be with your finger nail.

Yes, I agree, captured keys are really the only way to go. That said, I still carry a spare (but too long for most keys) solid key in my PB, along with a small wad of duct tape.

Don't know if this would work, but perhaps you could file a shallow groove in the bottom of the key where it sits against the barrel lug. Use inletting black or engraving clay on the key, install and remove it, Where the marking stops is the lug position and the spot for the groove. A series of shallow grooves parallel to the lug might also do the trick.