bess lock troubles

[engravertom]

Hello all,

determined to get going for next fall, I took my Pedersoli Bess out today for a few shots. I installed a fresh flint, loaded, primed, and made ready for the shot. The Cock seemed to stop as the flint hit the frizzen, and then went on down, setting of the priming and main charge. A serious "hang fire", and my shot went way low. This kept happening, but it seemed fine during dry firing, until it finally caught on the half cock notch one time when i tried to fire it again.

The trigger pull now seems lighter, and the half cock notch has suffered a bit of a burr on the edge. The nose of the sear is somewhat rounded and shiny.

I've had this gun for about a year or so. The previous owner had done several modifications. I have already straightened the barrel that was bent, and removed the brazed on rear sight. Now, it appears that the lock has some significant issues. he had told me that the trigger had been worked on.

I haven't really looked at it too closely,'til now, as the lock seemed to be working fine. Now, it is not! The lock plate has a bend in it. The bridle for the tumbler has a badly over sized hole, when the bridle screw is tightened down it binds the tumbler. I'll check the lock plate holes this weekend after disassembling the lock fully. I'm guessing there will be issues there also.

The tumbler looks OK, other than the burr from the sear nose hitting the half cock notch. The full cock notch appears to have the correct angle, but maybe is too shallow now. perhaps the sear nose is at fault.

Where to begin?

Dis assemble, straighten lockplate?
Clean up sear nose, re harden?
Could I buy a tumbler casting from Track and make that work as a replacement?

If the lockplate has an over sized tumbler hole, should I try and make a new tumbler? A new plate?

I'm guessing a Chambers lock with the over sized plate would not work,as i suppose the geometry of my Bess's trigger and touch hole would not make that feasible.

I could buy a tumbler and sear from Dixie. I wonder if their bridle would be a precision fit though. I'm guessing it would be better than what I have now.

I also doubt that there are any drop in locks that would fit, other than a Pedersoli? I don't want to spring for $200 for one of those. Unless that is my only option.

Thanks for wading through this. Any help would be appreciated. I do have access to a lathe, and heat treating options at work.

BTW, I have decided to try bending the stock at some point, as opposed to buying a replacement stock.

take care,

Tom

 

[J.D.]

Without having the lock in hand, it is almost impossible to diagnose the problem.

First, check to see if the lock works outside of the gun. Moving parts may be binding from over tightening the lock screws or lock mounting screws.

The burr on the half cock notch can easily be removed with a fine file.

As to the sloppy fit of the internals, that is pretty standard for the Pedersoli bess. IMHO, the internals are probably dead soft, too.

Based on personal experience, replacement parts will probably be as bad as the ones you now have...if they are in stock. They are usually back ordered, sometimes for loooonnnngg periods...and they are expensive.

About the only way to improve on the fits of the tumbler, bridle, and lockplate is to fill the holes for the tumbler axle, and redrill and ream them.

Binding of the sear and tumbler are common too.
IMHO, A new screw with a shoulder to stop on the lockplate is the best way to fix that. Though, backing off the screw a half to full turn works about as well and is less time consuming and less expensive.

Something else you might check is the clearance between the screw hole in the sear and the diameter of the sear screw. From experience, the clearance is usually about .010, it should be a coupla thousandths, so an oversize screw is in order. See the comment above about making a new sear screw, so you're killing two birds with one stone, so to speak.

A too lose fit between sear and the sear screw will allow the sear to cock to one side, preventing full engagement of the sear nose to full cock notch. Moreover, more friction is created by contact of the sear extension with the lockplate. I like to remove roughly 1/32" from the plate side of the sear extension to reduce friction in that area.

Polish the foot of the tumbler, where the mainspring rides, and the spring where it contacts the tumbler. Polish the sides of the tumbler, sear, sear bar where the trigger makes contact, and inside of the lockplate and bridle, and then harden the internals.

The frizzen might be too soft too, so that needs to be looked at.

Carefully straighten the lockplate using three round bars supported in a vise, by lengths of coat hanger through holes drilled near one the end of the bars.

Ideally, the inside of the plate should be dead flat, but some slight variation won't hurt.

I also suggest asking the original owner what was done to the trigger? While you are at it, ask if the lock was modified, in any way.

IMHO, a rounded sear nose is pretty standard for the Ped bess. It won't hurt anything as long as the full cock notch is deep enough and cut on the correct angle.

Remove the sear spring, with the rest of the lock assembled, cock the lock and see if the sear holds the tumbler, at full cock. You will have to manually engage the full cock notch with the sear nose, but it should hold with no pressure from the sear spring...or your fingers. :v

Be sure to back off the sear screw so the sear doesn't bind on the bridle prior to cocking the lock.

If the sear won't hold the lock at full cock, without spring pressure, the full cock notch is on the wrong angle. This is a potentially very dangerous situation.

If the sear holds, remove the mainspring and holding the lock vertically, with the front of the lock down, cock the lock and watch the hammer closely to see if there is any movement to the rear of the lock, when the sear is released.

If the hammer moves slightly to the rear of the lock before dropping to full down, it means that the full cock notch is undercut.

Neither condition is desirable, however, if the sear doesn't hold in the full cock notch, without sear spring pressure, that is dangerous.

IMHO, a problem with the full cock notch engagement, is not something you should work on. The angle of the notch can only vary a few degrees, so it is really easy to ruin a tumbler if you don't know what you are doing.

Those are the issues common to the Ped bess lock. Once the issues with those locks are corrected, they become reliable, sure fire, locks.

Your lock may have other issues caused by the previous owner's handiwork. If you can find out what was done to the lock and trigger while in the previous owners care, it might give some clues to what may be wrong with this lock, and how to correct the issues.

God bless,
J.D.

 

[engravertom]

Thanks JD!

I'll start with those ideas.

Thanks for the tutorial on the Pedersoli Bess locks!

Take care,

Tom

 

[rich pierce]

I'm thinking the first thing to try is to change your flint to bevel up versus bevel down or vice-versa and make it stick out farther, etc.

When the flint does not throw the frizzen open, it could be a problem with the internals of the lock only if the action is so rough it limits the force of the mainspring conducted to the cock throw. Otherwise it's a flint/frizzen problem. 1) Frizzen is soft and the flint is catching instead of slicing. 2) Flint not striking up high enough or at the right angle to throw the frizzen open.

The other problems need addressing, for sure, but may not be the problem with the frizzen not opening.

 

[engravertom]

Thanks Rich,

I'll look at those issues also. I appreciate the input!

Tom