Double-action flintlock rifle??

[frogwalking]

I have finished,  or s I thought, a new flintlock rifle from a kit.  It has a Chamber's Golden Age Germanic lock and a B weight .45 cal Rice bbl.  I can already see it will be an accurate shooter, but I need to sort out the sights before I get too enthusiastic.  Here is the issue.  I place the lock on half cock and pull the trigger.  It does not fire, the hammer does not fall, but it does move back noticeably.  Maybe as much as 1/8ch at the top, or a couple of degrees.  The trigger is a simple affair, pinned through the stock.  How can this happen, and what can I do to stop it?  I am afraid that one day, the hammer might fall.

[smylee grouch]

Are you saying that the hammer moves back when you pull trigger and its on half cock?

[kutter]

Your trigger has enough leverage the way it is set up to allow it to pull & move the sear when it's in the half cock notch.
That's camming the hammer back a tiny amount as the nose of the sear tip trys to escape the half cock notch.
It's a very small amt at the engagement point,,but you see the result as larger movement the farther you get away from that center. In this case the top of the hammer moving.

The shape of the sear nose and it's half cock notch can also be at fault for some of the allowed movement.

Worst case is that you can actually defeat the half cock notch with a strong enough pull of the trigger,,camming the hammer back just enough so that the sear nose slips out of the notch and the hammer falls completely.

With a primed pan, you could go off half cocked so to speak.

[frogwalking]

Yes.  I can't figgure out how this can happen, and therefore do not know how to fix it.   The pressure on the trigger necessary to make this happen is not excessive, maybe 8 or 10 pounds, however, the trigger is pinned fairly close to the sear bar, so the mechanical advantage is considerable.   Trigger pull to fire is 2 to 3 pounds.

I am afraid to  pull more heavily on the trigger to test it further, as the engagement portion of the sear may break.  Do you think this is dangerous, and therefore a problem?  Or....is is like the guy who told the doctor, "It hurts when I do this."  The doctor replied, "don't do that."

[PPatch]

Interesting problem, my trigger is pinned too so I will check if I have the same deal going on. Don't believe so but...

Thanks.

dp

[bob in the woods]

Check the shape of the sear nose, and the notch shape. If it is not right, you can have the sear nose slip out under some conditions, but I have to tell you that personally; I have a real distaste and sometimes strong words for anyone who purposely tries to defeat the half cock and make the hammer fall. Sooner or later, you're bound to break something IMO
The 1/2 cock position is not , to my mind, a safety. It should hold under normal conditions, but if you put a gorilla on the trigger, something will give in the end.

[Dphariss]

The sear is likely trying to pull out of the 1/2 cock. If you continue to try this and you pinned the trigger too close to the sear like less than 1/2" you may well break the tumbler and/or the sear. Having it pinned close and high can put a LOT of pressure on parts with a 10 pound pull.
Have you put a trigger pull gauge on it to see how much pull is really being applied?

Dan

[kutter]

I wouldn't continue to pull any harder on the trigger to see if in fact you could disengage the sear from the half cock notch by doing so. Maybe you can,,maybe you'll break off the thin half cock notch.
Neither will prove anything more than you already know. That is that the engagement of the sear nose and the notch itself is most likely less than what you need to keep it in position.

To check if the notch shape is at fault,,take the lock off and strip it of it's mainspring. Remove the sear spring too if you want complete control and feel of the process..
Then just using hand pressure to mimic  some light main spring tension, hold the sear into the half cock notch .
Slowly push on the sear with it engaged @ half cock  and see it you can get the tumbler to move/cam away from the sear nose. I'm guessing you may be able to push the tumbler right out of the way and the sear out of 1/2 cock with little effort once the mainspring is removed.
Close examination will show you where to reshape the notch and/or the sear itself to elliminate the camming action and instead in it's place make the sear do nothing more than press downward on the bottom of the notch itself.
Then it's doing it's job more efficiently,,but you can also see when an overly hard pull could still defeat it by breaking the thin lip of the 1/2 cock tumbler notch.
Don't trust your life to any of the so called half cock or 1/4 cock hammer safety or loading positions. Any of them can fail at anytime for a number of reasons.

[little joe]

Do you have clerance between the sear and trigger at half and full cock?

[Captchee]

As was said by Kutter and Dan , your caming the tumbler  do to  your trigger placement
 You basicly able to apply so much pressure to the  sear that  your starting to override the   pressure being applied  on the tumbler by the main spring
 If you pull your lock and look at the ½ cock notch you will see that it  angles back .
 The nose of the sear  matches that angle  and   is pressing down as you squeeze the trigger  . IE  the sear is trying to force its way out of the notch and is shearing along   the tumbler notch  .  In doing so its forcing the tumbler to rotate .
 If you continue to force the trigger , you will end up either breaking the  tip of the ½ cock notch or breaking the nose of the sear off

 On a side  note . This is one of the reasons a lot of production gun manufactures began increasing the angle of the  ½ cock notch OR going to a cut in notch vs. a  stepped type notch .
 With the cut in notch , the only way the sear can come out of the notch is if  the lock is cocked OR you apply so much force that you break the notch out completely
 You sometimes even see this with the full cock notch when there has been to great of an angle placed on that notch . IE the hammer or cock moves back before  it falls .
 In which case the sear must shear along the notch , caming the  tumbler back before it can drop free from the notch

[Acer Saccharum]

Check this: when on half-cock, can you jiggle the trigger a little? If you can, then the sear is completely into the notch. If you can't wiggle the trigger, then the trigger bar is too high, causing the sear to stay slightly compressed, and not allowing the sear nose to completely enter the half cock notch.

[frogwalking]

Yes Acer, I can jiggle the trigger a little at half cock.  From the answers, I am going to conclude that this gun is safe as is.  To those who think the half cock is not a safety device, pray tell, what is it?  Of course it is a safety device, although not a secure one for the many reasons stated. 

[Bob Roller]

The very fact it's not a secure safety negates it as such. It is an interference
system that is hopefully able to withstand the pressure exerted by the mainspring.
None of them will hold against a hard pull on the trigger.

Bob Roller

[frogwalking]

Acer, I did not mean to be disrespectful.  The rifle would fire from half cock when I first began investigating, and filing a few hundredths off the top of the trigger stopped that.  It was then that I noted it would pull the hammer to the rear and this was new to me. 

To the Bobs:  The half cock notch is what it is.   You call it whatever you wish, and I will do the same.

Thanks to all for the constructive comments.

[Dphariss]

On most flintlocks the 1/2 cock is as close to a safety as it gets. Its not nearly as secure and the "stalking safety" on a Manton or such but its all there is.
Its not a sear block or a lock on moving parts.
Its simply to make it a little safer.
I guess one might say its a relative thing. Compared to the full cock its safe. Compared to a number of modern guns or a flintlock with a better safety its not.

Dan

[bob in the woods]

I do not call the 1/2 cock notch a "safety" , simply because there is an actual safety incorporated into some locks, as Dan Phariss has mentioned.  I would point out that the Winchester Model 94 had/has a 1/2 cock position, and the later ones have an actual "safety"
It's really a matter of terminologies.  Proper muzzle control is more of a safety than any mechanical device IMO

[UpDok]

I have finished,  or s I thought, a new flintlock rifle from a kit.  It has a Chamber's Golden Age Germanic lock and a B weight .45 cal Rice bbl.  I can already see it will be an accurate shooter, but I need to sort out the sights before I get too enthusiastic.  Here is the issue.  I place the lock on half cock and pull the trigger.  It does not fire, the hammer does not fall, but it does move back noticeably.  Maybe as much as 1/8ch at the top, or a couple of degrees.  The trigger is a simple affair, pinned through the stock.  How can this happen, and what can I do to stop it?  I am afraid that one day, the hammer might fall.

It sounds like a nice kit with top quality components.

If it were my rifle, I'd try the half cock notch with the lock removed from the rifle. Does the sear still cam the hammer back slightly even when the lock is removed from the rifle stock? If it does, then the issue is probably with the sear nose/tumbler notch geometry. If it does not then the sear or some other associated part is probably rubbing in the stock lock mortise somewhere, or maybe there is not enough clearance between the sear and the trigger bar.
 
Since the hammer doesn't fall from the half cock notch when the trigger is pulled, the other question comes up; Is this really a problem?