Questions about the fly (in a lock, not your pants)

[Dave Markowitz]

As I understand, the fly in a lock is there to prevent the sear from getting caught on the half cock notch when firing a gun fitted with a set trigger.

Does this also apply if the gun is fitted with only a single trigger? I.e., is the fly necessary on such a gun?

I have a gun fitted with a large Siler percussion lock with a fly and a single trigger. I have no plans to remove it but if in the future it somehow broke or got lost if the lock is disassembled, would I be risking damage to the lock if I used it without the fly?

 

[bubba.50]

In a single trigger the trigger bar will hold the sear arm up long enough for the tumbler to pass the half-cock notch.

 

[rchas]

There's no real need for a fly when using a single trigger.

 

[52Bore]

Might depend if you pull or squeeze the trigger?
Most all original single trigger British Sporting/Target rifles have a fly in the lock (photo- Rigby & Alexander Henry).
Shotguns do not.

 

[FlinterNick]

A single trigger lock generally doesn’t need a fly, however if it has a fly it will make the action smoother when cocking. But otherwise not needed

 

[Dave Markowitz]

Thanks gents!

 

[Grenadier1758]

Tough question. It depends on how light your touch is on the trigger. If you have a trigger pull of 2 pounds to 4 pounds you will be lifting the sear off the tumbler. You will have a sear spring that is putting some pressure on the sear to hold it against the tumbler so the nose of the sear engages the notches. However, a very light finger on the trigger may not lift the nose of the sear past the half cock notch. Don't make the unset trigger pull so light and you won't get the sear dropping into the half cock notch.

 

[tenngun]

All of my locks have had flys.

 

[springfield art]

Waiting for someone to post a "fly in the ointment" comment!

 

[Dave Markowitz]

Tough question. It depends on how light your touch is on the trigger. If you have a trigger pull of 2 pounds to 4 pounds you will be lifting the sear off the tumbler. You will have a sear spring that is putting some pressure on the sear to hold it against the tumbler so the nose of the sear engages the notches. However, a very light finger on the trigger may not lift the nose of the sear past the half cock notch. Don't make the unset trigger pull so light and you won't get the sear dropping into the half cock notch.

My question was more of a hypothetical, to better understand the functionality and necessity of the fly on a gun without set triggers. Since the lock in question already has a fly, I fully intend to leave it in place.

 

[FlinterNick]

It’s a misnomer that flys are only intended for double set triggers. Flys do make a single trigger lock more effective, in the case with an improved baker lock

 

[GREENSWLDE]

Learned to my cost about light triggers and Half cocks.. I detented anything that was intended for competision those days. Also cut a second half cock on a light rifle I built for the hill years ago. The front 1/2 cock allows the gun to be carried ready capped for a quick shot. The hammer on that 1/2 cock is just .030" above the cap so it can't fall off.. It's a single set trigger on a Brazier stile 4 pin lock.
No worries if you fall over with gun loaded.. O.D. Sorry not the right photo.How do you deleat an unwanted attchment..Still Learning!!

 

[Va Hunter]

I had a TC new Englander and lost the fly. Without the fly when cocked and trigger is pulled it would only go to half cock. Replaced the fly and worked like it should.

 

[Kansas Kid]

Some will some won’t. Only sure way to know on your particular lock is to remove the fly and try it at the risk of damaging the the sear and tumbler. In theory it should not need a fly.

 

[jkelly]

OK, beat me to death if you wish; I am used to it & not offended.
By observation my P/H Enfield lock is not fitted with a fly.
But my P/H Volunteer certainly does (single trigger) - Following a recent lock repair the lock was refitted by an armourer kept snagging on the half cock sear when fired.
The lock was again disassembled and I was advised that the fly was not necessary and was removed.
After this the sear caught in the half cock every time the trigger was squeezed to fire.
It was the demonstrated that if I yanked hard on the trigger the rifle would fire and did - but I want to use it for target shooting and not against a foe closing on me at close range !

I disassembled again, wiped out excessive amounts of oil , replaced the fly so it would swing with gravitational force - Problem Solved.
The rifle now responds with a nice gentle trigger squeeze as it should every time and no potential damage to be caused to the sear by not having the fly installed.

My opinion, if your lock has a fly fitted leave it there and make sure that it moves freely as designed.

Good luck

 

[Kansas Kid]

OK, beat me to death if you wish; I am used to it & not offended.
By observation my P/H Enfield lock is not fitted with a fly.
But my P/H Volunteer certainly does (single trigger) - Following a recent lock repair the lock was refitted by an armourer kept snagging on the half cock sear when fired.
The lock was again disassembled and I was advised that the fly was not necessary and was removed.
After this the sear caught in the half cock every time the trigger was squeezed to fire.
It was the demonstrated that if I yanked hard on the trigger the rifle would fire and did - but I want to use it for target shooting and not against a foe closing on me at close range !

I disassembled again, wiped out excessive amounts of oil , replaced the fly so it would swing with gravitational force - Problem Solved.
The rifle now responds with a nice gentle trigger squeeze as it should every time and no potential damage to be caused to the sear by not having the fly installed.

My opinion, if your lock has a fly fitted leave it there and make sure that it moves freely as designed.

Good luck

Yes, I buy what you’re saying.