Back Action lock

[docone]

My question is,
Is there an advantage to a back action lock?
They were the last in the variants.
Was that a progression, or design?
Just curious. I am looking to my down the road build.

[rich pierce]

I think they are supposed to make for a stronger wrist/forearm transition.  Of course they were used on swivel breech double flintlocks but beyond that are pretty late period for most of the builders here to consider.

[RAT]

I believe they became popular with double barreled (side-by-side) shotguns because they could be mounted behind the breech area.

[Gaeckle]

I think that one reason would be the use of heavy, large accross-the-flat barrels.......the mainspring would be mortised in the wrist as opposed to under the barrel......the forstock could then be quite thin, 1/3 or 1/4 up the barrel side flat.....that would make for a light gun....large barrel with a small diameter hole, heavy barrel.

....just a guess based upon observations.....

[smokinbuck]

Besides strengthening the wrist they are "supposed" to be faster than a conventional lock.
Mark

[docone]

Lots of good info here. I know nothing on them.
Thanks guys.

[Pete G.]

I built a replica of an old family gun with one. Very short and strong hammer throw. Would probably work very well for a target gun.

[Bob Roller]

I made one 50 years ago and that was all I ever made.
I have seen some superb versions on high grade double
barreled guns. My Holland&Holland .303 deer stalker
had them with some of the most exquisite workmanship
I have ever seen. Jim McLemore has been after me to
make them but I haven'r made up my mind yet. I need
one more project like a moose needs a hat rack.

Bob Roller

[smylee grouch]

I was always under the impression that a back action lock took more wood away from the wrist, thus making it weaker. Will someone confirm this or explane why this isnt so, please? Smylee

[bgf]

I was always under the impression that a back action lock took more wood away from the wrist, thus making it weaker. Will someone confirm this or explane why this isnt so, please? Smylee

I was wondering the same thing myself, esp. if you put in a set trigger.

[Bob Roller]

 Even with intensive,dedicated inletting of the mechanism seen on the finest
English guns,the wrist area will be weakend.The installation of a double set trigger
will not help either.

Bob Roller

[Daryl]

The main intent, to me, was to strengthen the area under the breech/ breeches - especially with double guns. The reduction of wood removal over side locks, obviously helped in this regard, considerably.

[Feltwad]

The back action lock has we know today is mostly credited to a Mr Lovell who patented it  in 1834.Most of the top  London and Birmingham gun makers  had their own designs of this type of lock enclosed are but a few
Feltwad
A standard pair of back action locks fitted to a sxs percussion gun

Lancasters patent

Claytons patent tubelock

Safety device.

Nocks patent for the grip safety

[Acer Saccharum]

...and used on swivel guns much earlier.

[Jim Kibler]

... and on "over and under" guns of the 17th century.  Reference Simonin prints.

[Feltwad]

The early back action locks are not has we know today although they did go back to the  patch lock and flintlock period enclosed is a image of an early back action patch lock of approx 1810 by James Rowntree an English provincial gun maker
Feltwad

Rowntrees patch lock

[Hungry Horse]

 They definitely make the wrist weaker, but the main problem is the fact that the fall of the hammer drives the forward part of the lock upward in the mortise, if the front lock bolt doesn't pass through a tight hole in the breech plug. Other attempts to counteract the heavy upward thrust upon firing involved a lockplate extension under the drum, or snail, as shown in some of the pictures in previous posts. Many broken antiques are the result of some"gunsmith" taking a back action firearm apart, and opening up the hole in the breech plug to make it easier to get back together.
 Back action locks are quite fast, and can produce a heavy hammer fall without making the pressure required to operate a simple trigger oppressive. The advantage is in the length of the mainspring, I suspect.
 The L&R lock is a good choice, and if you run on to a Tryon back action lock snatch it up.
  While it is not wise, to dry snap any percussion lock, when it is out of the stock, with no nipple to stop the forward motion. Dry snapping a back action lock nearly always causes damage.

                      Hungry Horse

[Acer Saccharum]

While it is not wise, to dry snap any percussion lock, when it is out of the stock, with no nipple to stop the forward motion. Dry snapping a back action lock nearly always causes damage.

Drop the hammer onto a ingot of lead or piece of hardwood. Without that braking action, the tumbler and bridle will try to stop the hammer, with sure damage to the internals.

[Bob Roller]

 Snapping a caplock off the gun and against the bridle is a guaranteed
disaster. Broken screws,twisted bridle,wrecked lock plain and simple.
Some of the old British 4 screw locks have bridles as hard as glass and
they shatter instead of bend. I get them in once in a great while to make
a new bridle and that is fairly costly,about $100 or maybe more depending on the
complexity. When the weather cools off a bit more,I might see if I can make
a "Ruckliegendschloss" or back action lock patterned afer a very fine one in
a back issue of the Double Gun Journal.

Bob Roller

[Feltwad]

Have also come across several percussion back action locks fitted with a detent{Fly}
Feltwad

[Bob Roller]

 There are back action locks on top of the line guns that
are fully equal in all respects to any bar lock ever made
but we seldom see them.Most back action locks seen on
American guns are not a top quality lock and the same can
be said for the bar locks we find on old guns.Americans
were more into utility rather than quality. I had a new Goulcher
lock that was absolutely unusable and would have to be remade
to ever work on a new rifle.
I have noticed that top quality rifle locks,especially English types
have a fly or detent or intercepting cam whereas the same quality
lock used on a shotgun had no detent and both are fired by a single
trigger.I suppose both types rely mostly on fast action and sear
compression at the moment of release to prevent problems.
I have seldom found an American antique lock with the detented
tumbler and of the several Hawken/Gemmer originals examined,
I have never found a two position tumbler.

B ob Roller

[Acer Saccharum]

Back action locks were frequently used on high end target rifles of the mid-19th Century:  http://www.amoskeagauction.com/82/540.html

This is due to the large barrels and breech blocks. This style breech has a keyed or taper pin takedown feature.

[Bob Roller]

 If that sold for $2050,someone got one grand bargain.

Bob Roller