Sear catching on half cock notch

It's a Pedersoli Tryon back action lock. When letting the hammer down from full cock the sear taps the half cock notch. Doesn't catch on it but you can feel it bump it. The mainspring is very stiff and I don't know if that's the issue or is the trigger movement just a bit short. With the lock out no matter how hard I push on the trigger bar (?) and let the hammer down slowly it's still tapping that notch on the way by. This is the lock at full cock.

Is the fly missing or stuck? If not by holding the hammer it is not moving fast enough to keep the sear from hitting the 1/2 cock.

I had a flint lock on a pistol with a single trigger that had a similar problem. I removed the fly and it fixed the problem. The fly was much too low and catching every time.

I had one that would not hold at half cock. The sear spring was a bit dirty but the thing that caused it was the lock securing screws were like one screw driver bit blade thickness too tight. All the impression and trimming to improve the lock fit wouldn't change it. Just had to tighten the screws till it failed then back off just a tad.

Shouldn't be a problem if the fly is operating properly and freely, and the screws are not too tight in the lock.

The sear end of the main spring is too short. It’s bearing well back from the pivot point which is increasing the pressure needed to release the sear and restricting the movement of the sear.

Columbus said:

It's a Pedersoli Tryon back action lock. When letting the hammer down from full cock the sear taps the half cock notch. Doesn't catch on it but you can feel it bump it. The mainspring is very stiff and I don't know if that's the issue or is the trigger movement just a bit short. With the lock out no matter how hard I push on the trigger bar (?) and let the hammer down slowly it's still tapping that notch on the way by. This is the lock at full cock.

Click to expand...

Is it really bumping the half cock notch or is it bumping the fly?

Because the fly sticks up a little higher than the half cock notch, if the sear nose is riding against the tumbler as you lower the hammer it will often hesitate as it jumps over the fly.

Speaking of this, I often remind people that if their gun has a fly in the lock, they should never try to lower the hammer from full cock directly to the half cock position. The reason for this is, some guns have flys that stick up so proud they will actually stop the hammer when it is lowered with the thumb.
That gives the impression that the gun is on half cock so they think the gun is safe.
In reality, with the sear nose just pushing against the fly, any bump or jar of the gun can cause the sear to jump over the fly and let the hammer fall, firing the gun.

If the fly is just causing the hammer to hesitate but the gun works fine when it is fired with the set triggers set, don't worry about it.
Just make sure that the gun actually does go into the half cock notch when it is raised from the fired position. (Raising the hammer from the fired position pushes the fly out of the way so the sear nose can enter the half cock notch.)

By the way, don't remove the fly. It is needed for the set triggers to work like they should.

I agree with Zoni. If the lock works when set in the gun, don't worry about it. Back action locks are very fast, and I doubt you will notice the hammer falling when fired. I have a similar gun, and I noticed the same thing, but the lock works fine when put in the stock and firing.

Same gun but without the long range sights. .45 is a bit bbl heavy.

I have the same gun, but the deluxe model with the German silver trim work. Mine is a .50, but really a .51 because it shoots best with a .500 ball and a .015 patch.