Author Topic: Going off at halfcock! (Read 8957 times)

Robert Wolfe · « **on:** May 27, 2009, 03:29:25 AM »

I am going nuts, I can't figure this out so I'm coming to the experts.

I have a fowler I built (#2 of 3 so I am a novice) with a Chambers Early Ketland lock. It will go off at halfcock if I squeeze the trigger pretty hard - lots of creep. It doesn't go easy but I am not grunting either. I can't find any place that is rubbing. On the assumption that the lock internals are binding on the wood during cycling preventing the sear from dropping fully into the halfcock notch I took the lock out, put it at halfcock fully in the notch and put it back in. Yet it will still go off half cock. I am wondering if I pinned it wrong. The trigger is pinned about 7/16ths from the sear bar and 1/8 inch high. With a great deal of effort I can sometimes make the lock go off in my hand while at halfcock.

Thoughts? I'm stumped (which ain't that hard to do).

Jim Filipski · « **Reply #1 on:** May 27, 2009, 04:02:48 AM »

Robert:
Sounds like your sear bar isn't dropping into the proper place ( possibly binding) Taking the lock out and putting it back it isn't a true test. It has to fully cycle in the mortice for proof! This can drive you crazy. That bar isn't dropping down enough. Either wood or the trigger bar is stopping this
In my opinion

Jim

Dave B · « **Reply #2 on:** May 27, 2009, 04:24:37 AM »

Robert,
If you can hold the lock in your hand and with sear fully enguaging the halfcock and make the mechanisim fire the lock should be sent back to Chambers to be looked at. I would before doing that get out the magnafying glass and look at the sear nose(chipped or broken) and the half cock notch make sure there is not any debrise or flaws that would prevent full engaugement. I have multiple Chambers locks and none of them do this. Jim and Barbie will make sure its right. I would bet that the nose of the sear has been damaged. It would explain being able to pull it out of the half cock notch.

Jim Chambers · « **Reply #3 on:** May 27, 2009, 04:45:25 AM »

The operative phrase here is "with a great deal of effort I can sometimes make it go off in my hand." With a great deal of effort I can make virtually any lock go off from the half cock position. If one pushes hard enough of the sear it can cause the tumbler & cock to cam backward enough for the sear nose to come out of the half cock notch. Again, the emphasis is "with a great deal of effort." If the trigger is pinned high in the stock to get good mechanical advantage and you squeeze hard enough on the trigger you will notice the cock moving backward and eventually falling.
I first encountered this at Dixon's several years ago. I had sold a custom rifle (not one of mine) to a gentleman. A couple of hours later he brought the rifle back complaining that it would go off at half cock. I put the lock at half cock and squeezed the trigger. Nothing happened. The gentleman told me to squeeze harder. I tried squeezing the trigger with all the strength I had and was finally able to make it fire from half cock. I later tried every rifle I had in the shop, and all would do the same thing if I applied enough force to the trigger. Either the cock would cam backwards or the half cock notch would break off.
What dumbfounds me is why anyone would want to squeeze a trigger that hard to start with.
As always, I'm glad to check out anyone's lock if they think there's a problem with it. But, in this case I doubt there is a problem with the lock.

D. Taylor Sapergia · « **Reply #4 on:** May 27, 2009, 07:03:31 AM »

Many people are under the mistaken impression that the half cock position is a SAFETY. I do not believe that it is. It is simply a safer position to set the cock for priming, and provide some small manner of confidence that the gun won't go off if jarred, like when you're hunting. Many do not prime until the last second, but I personally prime when I begin a stalk, or am in country where game encounter is immanent.
When we shoot in company, as in on the trail, we do not prime until we have stepped forward of the group to the shooting position.
There is only one commercial lock of which I am aware, that has a factory installed sliding safety. It's on the Mortimer half stocked gun/rifle.

jerrywh · « **Reply #5 on:** May 27, 2009, 08:08:55 AM »

At some point your going to break off the tip of the sear or break the halfcock notch. Your not supposed to pull that hard.

Jim Filipski · « **Reply #6 on:** May 27, 2009, 02:19:13 PM »

One of the points I was trying to make is ( and I have seen this plenty of times) Is that if the mortise or trigger bar is slightly preventing the sear from reaching its proper position ....taking it out of the stock at half cock at that point, has the lock set up in such a fashion that it will go off at half cock when it is out of the gun sometimes with the slightest touch. I was interested to see if this was the problem.
If it is going off at half cock when the lock is properly cycled through the tumbler out of the stock it could be a "heavy hand" as Jim was talking about. However this also can happen if you decided to tighten up the bridle screws ( especially the sear screw) If you don't have the proper slack in the sear screw you can be causing the bridle to create too much friction causing all types of bizarre problems with the workings of the lock
Jim

Acer Saccharum · « **Reply #7 on:** May 27, 2009, 03:14:25 PM »

Agreed with Taylor that half cock is not a safety, but adds a low level of security. Why is it called half cock? Because it's not a safety.

I can say that most home built guns I have worked on had problems with the halfcock notch. Sometimes the notch is broken out. Sometimes the tip of the sear is chipped back. Sometimes the wood of the stock prevents the sear from fully going into the notch.

In all the above scenarios, the lock looks and sounds like the halfcock is working. In reality, the gun can be fired from that position.

Don Getz · « **Reply #8 on:** May 27, 2009, 03:49:57 PM »

Jim beat me to the punch on this one. If you pull hard enough, you can force the sear out of the half cock position, but,
it does take a lot of effort. This is probably one of the reasons he has to replace tumblers in locks, because people who
have them in half cock just keep pulling on that trigger, thinking it is just a hard pull. It is difficult to make something that
is totally idiot proof...............Don

Longknife · « **Reply #9 on:** May 27, 2009, 04:19:16 PM »

I believe the English army tested their muskets by hanging the gun, by the trigger, on your finger while on half cock. If that did not make it go off it was OK......Ed

Roger Fisher · « **Reply #10 on:** May 27, 2009, 04:51:23 PM »

Quote from: jerrywh on May 27, 2009, 08:08:55 AM

At some point your going to break off the tip of the sear or break the halfcock notch. Your not supposed to pull that hard.

Or snap a set trigger while she is on half draw! Tends to break out the half draw notch!

Roger Fisher · « **Reply #11 on:** May 27, 2009, 04:57:40 PM »

Robert: Have you done any 'stoning' on the sear nose??? Only asking!

If you did you may have shortened said sear nose to the point that it can't fully engage the notch deep enough and allows you to 'drag' it out with that heavy hand. Just a suggestion to right the problem!

Dphariss · « **Reply #12 on:** May 27, 2009, 04:58:31 PM »

Quote from: Robert Wolfe on May 27, 2009, 03:29:25 AM

I am going nuts, I can't figure this out so I'm coming to the experts.

I have a fowler I built (#2 of 3 so I am a novice) with a Chambers Early Ketland lock. It will go off at halfcock if I squeeze the trigger pretty hard - lots of creep. It doesn't go easy but I am not grunting either. I can't find any place that is rubbing. On the assumption that the lock internals are binding on the wood during cycling preventing the sear from dropping fully into the halfcock notch I took the lock out, put it at halfcock fully in the notch and put it back in. Yet it will still go off half cock. I am wondering if I pinned it wrong. The trigger is pinned about 7/16ths from the sear bar and 1/8 inch high. With a great deal of effort I can sometimes make the lock go off in my hand while at halfcock.

Thoughts? I'm stumped (which ain't that hard to do).

What Jim Chambers said.

Dan

Z. Buck · « **Reply #13 on:** May 27, 2009, 05:09:13 PM »

well i have heard of another guys in the same situation, from one of the local gunsmiths that is a member of my blackpowder club. im sure he started out with a perfectly functioning lock, by the time he got done showing everyone what he could make his gun do, he didnt have a halfcock notch left, he wore/broke it right off, so you should make sure that everything is still in good working order and that the sear nose drops all the way into the halfcock notch

G-Man · « **Reply #14 on:** May 27, 2009, 06:14:35 PM »

Do you have a tiny bit of clearance between the trigger and sear at all lock positions (half and full)? If not, the trigger might be pressing against the sear and keeping it from fully engaging the half cock notch.

On some locks (the L&R Queen Ann for one) the sear sits in different positions when the lock is at half and full cock - i.e. the sear sticks out farther at half cock and so when guys fit their triggers to minimize play in the trigger when it is on full, the trigger ends up pressing against the sear at half cock and prevents full engagement of the notch.

Regardless of the lock if there is not a slight amount of loose wiggle in the trigger at all positions, the trigger is pushing on the sear and should be fixed by careful removal of metal from the trigger till it clears the sear in both positions.

Guy

Bill of the 45th · « **Reply #15 on:** May 27, 2009, 06:22:38 PM »

I had the half cock notch not engage properly on one lock, and it turned out to be some debris that got into the notch that the fly sits in. It made the fly prevent the full engagement of the sear into the notch. You might take the lock apart, remove the fly, then reassemble, and try it, to see if it might be the problem. Also the fly's position may make it hard to see if it is the problem. It's not really needed on single trigger guns in most cases, just on those with set triggers. I have had to increase the notch on a couple of locks to improve their hold, but that was years ago. Never had a problem on one of Jim's.

Bill

Cory Joe Stewart · « **Reply #16 on:** May 27, 2009, 09:12:15 PM »

Eveyone on here probably knows waaaayyyyyyyyyy more about this than me. I had a similar thing happen to me in that a gun would go off half cocked and without any pressure. One time it went off when I brought it to my cheek to aim.

Here is what the problem was. I bought the gun and it was very well made by a known maker who will remain nameless, the lock was an L and R lock and would fire under water I think if I tried it. I took it to a friend of mine who builds guns and he said it was not the lock. The lock mortise to to tight and after taking it in and out over the years the lock was pushing further into the mortise and the sear arm was catching inside the mortise to we filed about an 1/16 off of it. Never had another problem with it, then I hocked it to pay for grad-school.

Good luck with it

Coryjoe

Stophel · « **Reply #17 on:** May 27, 2009, 10:11:45 PM »

Some of the military reenactor units require their particpants' guns to hold half cock while holding the gun by the trigger. Makes me cringe.

Half cock is not a safety. That tiny little slip of metal ain't that strong, and if you keep yankin' on it, it will break. Besides, virtually any lock will go off at half cock if you pull on it hard enough. The sear nose will lever half cock notch down and out of the way. It's just the nature of the design.

Basically, it's just a reminder that you don't have the gun on full cock yet...

jim meili · « **Reply #18 on:** May 27, 2009, 11:14:58 PM »

I have worked on a lot of old guns and it is quite common to see a half cock position that is cut to fit the nose of sear perfectly while the full cock has an angle that allows only the tip the sear to contact it. This is especially true with double shotguns and some really nice ones too. The half cock position was a place for holding the hammer, not really a safety.

On a contemporary lock this postion is designed to give a secure holding spot and not a place to fire the gun from. Keep it up and you are going to break something in there. On the other hand I have an original Brown Bess and it locks up securely at half cock. I suspect they didn't want the rear rank shooting their fellow soldiers while under fire and keep in mind that many of these young soliers were not experienced gun handlers like the sportsman in the field might have been.

Robert Wolfe · « **Reply #19 on:** May 28, 2009, 04:22:40 AM »

Thanks for all the responses. The sear seems to fit nicely into the halfcock notch. This lock had a broken halfcock notch after the first few shots and Jim Chambers kindly fixed it so I do not believe it is the lock nor have I touched the internals. There is a very small amount of play between the trigger and the sear bar so I do not think it is that.

It takes effort, but not of the Neanderthal type, to fire it at half cock. Less than I would like but it is enough that you would not do it accidentally. Nor do I think a bump would set it off. I have a Chamber York that I can't fire at halfcock - at least not with the same amount of effort.

I only found out that I had this problem last week by accident - I've had the gun for over a year now. I'll keep looking for a place where the lock is binding but I am stumped at this point.

ironwolf · « **Reply #20 on:** May 28, 2009, 04:55:18 AM »

Let off the trigger mainspring untill the R. trigger has a wee rattle.

Jim Chambers · « **Reply #21 on:** May 28, 2009, 04:57:43 AM »

Robert,
If you are coming to Friendship in June bring the rifle along. I'll be glad to take a look at it and see if we can figure out what is going on with it.

Robert Wolfe · « **Reply #22 on:** May 28, 2009, 11:41:47 PM »

Jim, thanks for the offer. If I make it down I will look you up.

bryanbrown · « **Reply #23 on:** May 29, 2009, 03:59:49 PM »

The "old school" "traditional" test assuming it is not a set trigger but a single trigger is to hang the arm by the trigger with the cock on half cock. It should hold the weight of the arm without firing. If you pull hard enough every half cock will fail. I have one musket I commonly use as a loaner for new reenactors. One guy fussed about the 1/2 cock not working. He had actually pulled so hard on the trigger at 1/2 cock he broke the nose of the sear off in the half cock notch. Half cock is half cock, You are the safety.

Dphariss · « **Reply #24 on:** May 29, 2009, 06:08:54 PM »

Quote from: bryanbrown on May 29, 2009, 03:59:49 PM

The "old school" "traditional" test assuming it is not a set trigger but a single trigger is to hang the arm by the trigger with the cock on half cock. It should hold the weight of the arm without firing. If you pull hard enough every half cock will fail. I have one musket I commonly use as a loaner for new reenactors. One guy fussed about the 1/2 cock not working. He had actually pulled so hard on the trigger at 1/2 cock he broke the nose of the sear off in the half cock notch. Half cock is half cock, You are the safety.

Heh heh!
I learned while running a Motel years back that the average human is, well, "average". A frightening number cannot find a 19" TV in a Motel room Or 6-8 towels in a bathroom. Yeah, really.
The weight of some muskets could likely be held by the full cock notch. 10-15 pound triggers on muskets would not be outside the norm.
But putting 40-60-80 pounds of pull on a trigger to make it "fire at 1/2 cock" is just ignorance or stupidity.
With the leverage of the trigger and sear pivots its possible to put several hundred pounds on the sear nose.

The "safety" vs the 1/2 cock.
The safety found on "modern" guns is a BLOCK in most cases. It uses a steel bar or block to PREVENT sear movement. Most are very strong (for the reasons we see mentioned above) if you have a block of steel supported by another block of steel that stops trigger/sear movement. This is a FAR different situation than the perhaps .020/.030" thick unsupported sear nose or 1/2 cock notch.
The sear and notch are fragile by comparison. They will do their job which is keeping the lock from falling out of 1/2 cock by accident or from a normal trigger pull. But they will not stand abuse very well. Simply snapping a set trigger with the lock in 1/2 cock is enough to break lock parts if done to any extent.
We need to understand that we are not working with a 20th century striker fired firearm but a side lock firearm with FAR different design and safety criteria and not an "absolute lawyer proof" safety as found on many modern guns.

Dan

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Author Topic: Going off at halfcock! (Read 8957 times)

ironwolf

bryanbrown