Lock Jar?

[Darkhorse]

Has anyone ever had a lock that would jar or move the bore off target before the rifle fired? Any mention of this has always been associated with using set triggers.

[Turtle]

 I always thought this was the reason target shooters use a small lock wit a lite hammer. There also were some rifles with the hammer swinging backwards-toward the shooter to help this.

[Larry Pletcher]

Back in the '80s and the Bowling Green Seminar Lynton McKensie told this story.  He owned an original Staudenmayer rifle that had very harsh springs.  He felt the jar in firing was a problem and decided to make a milder spring set for it.  He told our class that his scores went up with the milder springs.

This was the first year I had a way of timing locks, and I asked Lynton if I could time the lock with both sets of springs. He sent me the lock with both sets.  The harsh spring set was slightly faster; while the milder set was more consistent. I believe he was right. I wouldn't say this is true of all locks, but in Lynton's case it was true.

The lock holds 2nd and 3rd place in my all time list of fast locks. An original Joseph Manton is number 1, while the Staudenmayer with harsh springs is number 2, and the lock with mild springs is number 3. (This was reported in Vol. 4 of the "Journal of Historical Armsmaking Technology").

Regards,
Pletch

[Pukka Bundook]

I wonder  Larry, if that is why in Europe, shoots with matchlock target arms remained popular long after the matchlock was superseded by more advanced ignition systems?
As we know, a matchlock can fire Very fast.  (Do you know of any lock time data for these?) and with the snap-lock, the trigger -pull is next to nothing at all. That, plus the very light spring and serpent /match holder, mean no jar whatsoever.
I don't mean to drag this topic off focus, but see it as somewhat relevant.

Highest regards,
Richard.

[Pukka Bundook]

Double post , apologies!

[OldMtnMan]

Could be something to this. I had a Johnathan Browning Hawken that had the strongest main spring I ever felt. That gun never shot as accurately as I thought it should.

[Larry Pletcher]

Richard, Pete,
I mainly have data on flintlocks.  I did time one wheel lock, but have not had access to a matchlock.  The jar caused by the lock has prompted thought, but that is a tough one to measure.  I have thought about buying a 3 axis accelerometer to measure gun movement.  It's probably more than I want to mess with now. The lock jar would likely be covered up by recoil when the barrel ignited.  With a good lab and unlimited resources, it does sound fun to tackle.
Regards,
Pletch

[OldMtnMan]

Well, I had to blame it on something Pletch.

Maybe the gun wasn't that accurate, or maybe I just had a hard time holding a 10lb gun in the offhold position.

[Hungry Horse]

Lock jar? Ain抰 that the stuff my granny warned me about after I stepped on a rusty nail.
 I once owned a kit gun that had a stiff spring in the double set triggers, and a stiff mainspring in the lock. My shooting with this gun was mediocre at best. But one day I shot it without setting the trigger, and bettered my previous score. That got me thinking, and I reduced the tension in the mainspring as well. It improved the accuracy by a bunch.

  Hungry Horse

[OldMtnMan]

Usually, not setting the rear trigger makes the front trigger a real hard pull. I've seen some as high as a 15lb pull.