[/quote] I would think the mechanism for that would be quite complicated and something of a PITA to maintain, etc. But what were the advantages and disadvantages of the system? It certainly is an interesting gun[/quote]


Originally Posted by BrentD, Prof
Originally Posted by FlyChamps
Originally Posted by limapapa
A marvelous gun! I show my ignorance, but how do the barrels close over the proud breech face--looks like at least 1/16 inch sticking out, maybe more. Thanks.

The opening lever linkage first moves the barrels straight forward a short distance to clear the breach face before they drop. That was Dougall's patent.

I would think the mechanism for that would be quite complicated and something of a PITA to maintain, etc. But what were the advantages and disadvantages of the system? It certainly is an interesting gun

Dougall believed that the main weakness of the breechloader was that the breeches rose upon firing, thereby causing a gap to be formed between the barrels and the standing breech, and the resulting loss of gas weakened the charge's strength. His solution was to have raised bosses on the breech face, which prevented the breech-ends of the barrels moving in any way, and an eccentric hinge pin which allowed the barrels to move forward when opening the gun, and move securely backward when closing the action. Dougall allowed his popular action to be built under licence by other gunmakers, but the highest grades he had made on his premises. While a vehement opponent to the breechloader at first (notably his book Shooting Simplified in 1857), he changed his tune with his Lockfast invention, which he patented in 1860. He became a very vocal proponent of the pin-fire, and his Lockfast proved very strong in both game guns and rifles, well into the central-fire period. It's only drawback is that it is slow to operate, not being a snap-action.

The 4 May, 1861, edition of The Field included the following:

DOUGALL’S LOCK-FAST BREECH-LOADER

Necessity has been wisely said to be the mother of invention, and to the truth of this aphorism the sporting world is indebted for the application of a great mechanical principle to the construction of breech-loading firearms. Mr Dougall, the possessor of one of the oldest gunmaking establishments in the kingdom, and favourably known to our readers under his signature of “A Glasgow Gunmaker,” finding his cautious countrymen resolved to await the improvement of the “Lefaucheux” gun, confessedly incomplete through the want of any actual locking of the barrels and stock together, set himself to solve the problem, and to do what for twenty years had been pronounced an impossibility, viz., to let the barrels of a “Lefaucheux” gun work upon their hinge-pin, and yet interlock with the false breech. After digesting many plans, and seeing their intrinsic weakness, he finally hit upon the ingenious method of converting the hinge-pin, hitherto a fixture, into an eccentric rod acted upon by a lever, the two representing a locking power which he modestly estimates at 600lb., but perhaps 1000lb. would be nearer to the mark. Not only is a better catch thus obtained, but that catch is at the extreme end of the barrels, the only point where a perfectly solid grasp can be attained. The same pressure acting upon the cartridge, necessarily places it most solidly against the breech, thus diminishing the recoil, and increasing very much the shooting powers of the gun. The value of the invention was seen at once, and large sums were offered for the patent right. These offers Mr Dougall has declined, and has (wisely in our opinion) thrown the invention open to the trade on a moderate royalty, being convinced that this will in no way be adverse to his own private demand, already beyond his powers of supply. We may also mention that at a meeting of the most extensive Liège gunmakers, it was resolved, nem. con., to adopt the invention; and with such rapidity and energy was the matter carried into effect, that before leaving Liège Mr Dougall saw a large number of guns put into workmen’s hands. By another ingenious invention the gun can at once be converted into a muzzle-loader. A moveable brass breech is placed in the barrel. This is not new, but hitherto it had always to be removed to receive a new percussion-cap after every shot. Mr Dougall does away with the percussion-cap altogether, but not knowing whether or not he intends to take a patent for this separate invention, we shall only here state that the plan is most effective, and enables the gun to be used with all the other facilities of a muzzle-loader, while his lockfast action renders this moveable breech much more secure than in the gun as commonly made.


As to what the pin-fire version of his Lockfast looked like, here is a 16-bore sold from Dougall's London shop, number 1750, dating from 1864:
[Linked Image from i.imgur.com]