FIXED! Russ Hamm lock not holding at full cock

[bones92]

My Cornell Kemper .45 rifle has a Russ Hamm flintlock, probably from the early 70's (according to Marvin Kemper's estimate).

Recently it has started to fail to hold at full cock.  I thought perhaps something was binding on the sear, but I think it is more likely wear on the tumbler.   Even with the lock out of the stock, I can push the back of the cock and it will fall (i.e. without lifting the sear arm).  Sometimes it takes little effort, sometimes more, but while in the stock, sometimes the lock just doesn't hold at all, or holds for a few seconds and falls on it's own.

Bottom line, the rifle is out of commission until this is fixed.

Some other seasoned shooters at our club suggested a good smith could clean up the tumbler notch and/or sear engagement to restore proper hold.  I will post some photos of the tumbler and sear.


Hoping I can get this lock back into action.  I only shoot this rifle a few occasions per year, but I have no idea how much service it saw before I bought the rifle. 

I tried to show the engagement of the sear and tumbler notch.  Does this look worn, and can I possibly freshen up the notch and sear?

[bones92]

I will add, I took the lock off and cleaned it between relays yesterday. I thought perhaps just some carbon fouling was keeping the sear from seating fully at full cock, but the issue remained.  It's inconsistent, too.   Sometimes the lock will hold at full cock, other times it will immediately let go, sometimes hold for a few seconds and then release.

My Cornell Kemper is my favorite shooter, so the sooner I  get this fixed, the better.  (I actually bought an identical, unused Hamm flintlock for it, but before I give up on the original, I'd like to try to restore it to good service.)

[wattlebuster]

If I were you I would send it to Brad Emig an it will be right when it comes back to you

[smylee grouch]

I second wattlebuster's idea. Cabin Creek Muzzleloading.

[Hungry Horse]

 It looks like the full cock notch if damaged, and the nose of the sear is worn, or broken.

  Hungry Horse

[Daryl]

It looks like the full cock notch if damaged, and the nose of the sear is worn, or broken.

  Hungry Horse

That's what I see - looks like the nose of the sear is gone/worn/broken off and also the full cock notch is worn.

[bones92]

I suspected such. Is this repairable?

[Daryl]

Sure everything is repairable - new sear, or sear tip if someone knows what they are doing with good enough weld material and/or treatment.
Looks like enough material in that sear to "form"/forge a new tip, then harden and temper.
Needs work on the full cock notch as well.

[bones92]

This is a photo of the new, never-used Russ Hamm lock (I bought this to eventually replace or repair the original lock, but I thought it would be many years before the lock needed replacing).   The sear engagement of the full cock is evident.

I tightened the upper screw on the original lock (the upper most in the photos) and that seemed to help a bit... but I can still push on the back of the cock and cause it to fall.  I assume that a properly functioning lock should NOT release unless the sear lever is lifted, regardless of force.

[JPK]

Something to look at also is the hole in the lock plate and bridle. If the fit is getting worn that will allow the tumbler to wobble and along with the worn full cock notch will make for an inconsistent engagement with the sear.

[bob in the woods]

I too suggest sending that lock to Brad Emig at Cabin Creek.  It is 100% unsafe as is and needs to be repaired.

[Bob Roller]

These locks were NEVER a quality item and the fact that any of them are still in use is amazing.
They proved that precise fits and hardened parts are really not needed until much later.
There are shops that can fix these but I have no idea who and where that are.
Bob Roller

[bones92]

I have the 2nd brand new Russ Hamm lock already.  I may just have it fitted, drilled and tapped and start using it.  The original lock has been on the rifle since the early 70s, and I have no idea how much usage it has seen. I've had it just over 5 years, and doubt I've had it to the range more than a dozen times, so realistically, I've put maybe 250 rounds through it. 

I've considered the possibility of just switching to a newer lock, like a Chambers or L&R... something that would fit.  But given that I have the spare Hamm lock already, it's probably more cost effective to use it.

[Hungry Horse]

 The cheap dirty fix for these locks,  is to find an early CVA lock with low usage, and use the internals. CVA copied Russ Hamm’s lock, and the parts interchange. You will probably have to change the tumbler, and sear, to get it to work. These parts aren’t any better, they’re just more available.
 The real fix for this is to either  get one of the L&R replacements for the CVA, or convert the internals from a Siler, or some other similar size, good quality lock, to fit yours.

  Hungry Horse

[Standing Bear]

I contacted L&R for a flintlock to replace a Russ Hamm. Good lock good service. Got one not drilled and tapped for a lock plate screw. 👍

[D. Taylor Sapergia]

bones:  does your rifle have a set trigger, or just a simple trigger?  The nose of the sear and the full cock notch need a little tuning is all.  I see in the "new" lock that the maker simply rounded and polished the nose of the sear to get a smooth light let off.  The problem with that system is that with just a little tumbler notch wear, that lock too will become unsafe, and will not hold at full cock...the engagement of the sear/notch is very delicate.
The geometry of the sear/tumbler notch relationship is damaged in your old lock.  The correct full cock angle is a radius line drawn through the centre of the tumbler to the outside of the tumbler.  The sear's nose should also be stoned and polished to this same angle.  This is simple to describe but not so easily accomplished, so whether you have the ability and patience to do this, I cannot say.  It is easy to remove too much metal from either or both parts and you end up having to replace the parts.  The lock will have to be disassembled and reassembled many times, likely, before the fit is perfect, but it can be done with patience, and is something that we all should know how to do, at least in theory.  And don't rely on the sear spring to provide the tension to hold the sear in the notch...it must stay there without the spring.If you end up with those angles too acute, the only issue will be a hard trigger pull...there is such a fine line between a light crisp trigger pull and a lock that is unsafe or a bugger to fire.

[bones92]

D. Taylor, yes it has a set trigger. 

I think you're right, and the geometry of the engagement between the sear nose and full-cock notch needs to be corrected.

I'm sending the rifle and the new lock off to Marvin Kemper.  He will fit the new lock for the rifle, and hopefully be able to remediate the original lock.  I'd like to keep on using the original lock as long as possible, then eventually swap out the new lock, maybe when my son is grown.  In the interim, having two (identical) locks wouldn't be so bad, either. 

I truly love shooting this Cornell Kemper rifle.  It is both comfortable and accurate.  When I do my part, it puts 'em in the black consistently.  I just need to address the glare on the front sight blade (our range is generally south-facing, so midday sun really reflects off the blade).   I may try notching the back end of the sight blade.   

[Daryl]

Sight glare is most easily corrected with a flat-black erase-able sharpie.
I always carry one in my possibles and/or shooting box, now. I had tried the spray can of sight black, but the
erase-able sharpies (felt-pen markers) are not only as good, but cheaper & longer lasting as well. Easy to use
and remove. The shape of the sight is not important, they work.

[Robby]

I mad some hoods that are friction fit on the sight base, slips on and off with ease. I take them hunting should the need arise. I also carry "White-Out" and a flip up and down pair of shades with a pin hole. Hey, its not perfect, but I'm still out there and successful. Old, nuff said.





Robby

[bones92]

So a follow up is in order...

I contacted Marvin Kemper and sent him the rifle and the "new" lock.  He was able to restore the original lock to fine working order, and he fitted the "new" Hamm lock.   And to boot, he turned it around in just a few days.

So now I have the original lock ready for more service at the range, and someday when I pass this rifle to my son, he will have a "new" unused lock to drop right in.

I spoke with Marvin, and I was surprised to learn that I'm not the only one who has sent one of his dad's rifles for him to repair or upgrade.  Of course, with Cornell Kemper having made an estimated 3,000+ rifles, I shouldn't have been surprised.  Marvin said he gets one of his dad's rifles in for work about every month or so.   We laughed at the fact that his old pop was keeping him busy, even from the Great Beyond.     

And I was able to get it to the range this past weekend.  I invited a friend from the gym who had never shot a muzzleloader before, as well as my brother-in-law.

Anyway, I'm very pleased.