AN IMPROVEMENT OR IMPROVEMENTS IN 'LOCK-PAST' BREECH-LOADING FIRE-ARMS
Year: 1869

page_text: PROVISIONAL SPECIFICATION left by James Mackic at the Office
of the Commissioners of Patents, with his Petition, on the 1st
May 1869.
I, JAMES MACKIE, of No. 59, Saint James' Street, in the City of
Westminster, in the employ of James Dalziel Dougall, of the same Place,
Gunmaker, do hereby declare the nature of the said Invention for "AN
IMPROVEMENT OR IMPROVEMENTS IN 'LOCK-PAST' BREECH-LOADING FIRE-ARMS," to
be as follows:-
The Invention consists mainly of an improvement upon James Dalziel
Dougall's Invention of "Improvements in Breech-loading Fire-arms,"
for which Letters Patent were granted to him on the Seventh day of May
One thousand eight hundred and sixty, No. 1128, which breech-loading
fire-arms are known by the name of the "lock fast" guns.
In making my improved lock-fast gun I form what is called the action
of the gun so that when the breech is closed and the gun ready for
firing, the breech end of the barrels being close up to the false breech,
and firmly held there by the eccentric head of the lever, as herein-after
described, the hook which corresponds with the hook of Dougall's lock-
fast gun, and which is at the front end of the lump, instead of resting

page_text: against the hinge pin as in the lock-fast is at a little distance behind it.
The cavity in the lump in which the head of the lever works closes down
upon a solid piece left in the action of the gun, and so arranged that
the solid piece and the eccentric head of the lever together exactly fit
and fill the cavity. By this arrangement the hinge pin is entirely
relieved from the recoil, which is received by and distributed over the
whole of the remaining portion of the action of the gun. I also form, as
is done in the lock-fast gun, a holding lug on the breech end of the
lump corresponding with a slot in the action of the
gun, but in my gun,
as the barrels are shut down, the internal face of the cavity in the lump
.comes down upon the eccentric head of the lever so arranged that a
slight longitudinal motion is thus given to the barrels towards the false
breech, causing the holding lug to enter the slot, and thus holding the
breech end of the barrel in its place until it is firmly fixed there by the
action of the lever in the usual way. The action of the lever in giving
this preliminary catch is assisted by a spring suitably placed so as to
press the lever towards the position it occupies when the gun is ready
for firing. The breech end of the barrel may be prevented from rising
up by any suitable arrangement of projections and recesses corre-
sponding accurately with each other upon the breech end of the barrel
and lump on the one hand and on the action on the other. When the
lever is moved forward for the purpose of opening the barrel its eccentric
head acts upon a square or other conveniently shaped piece of steel
passing through the solid piece of the action above referred to, and
pressing against the back part of that portion of the lump which forms
the hook, thus forcing it with the barrels forward till the hook comes
upon the hinge pin, and the barrels are moved sufficiently forward to be
clear from the false breech, so that the breech end of the barrels can rise
and the breech be opened in the usual way. As soon as the lever is
released from the hand pressure the spring before mentioned causes the
lever to resume its former position. I also make the pin hole that
goes through the head of the lever and upon which it turns of an
eliptic form, so that when the breech is closed the pin is relieved from
all strain.