Why the "patent breech" design ?

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Hi Kyron,
It depends a bit on the design. The theory of the patent breech with its recessed powder chamber only works if the recessed chamber is considerably smaller than the bore of the barrel such that it only hold a small portion of the total powder charge. In that design, the small chamber is ignited by the cap or priming, and explodes directly into the middle of the main powder charge, igniting it instantaneously. Contrary to what some think, this does not speed ignition but makes the combustion of the main powder charge more efficient producing more gas pressure in the bore per powder charge. It really works. A rifle I built with such a breech used 20-30% less powder for the same performance. If the breeches on the guns you mentioned have chambers the same size as the bore, there is no real advantage. The main charge is going to be ignited from one side and there will be a slight "fuze" effect as it sequentially ignites the main charge just like a barrel with flat breech plug. Perhaps if the bottom of the chamber is rounded rather then flat, it might concentrate ignition toward the center of the charge but I suspect that effect would be small.

dave
 
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If the breeches on the guns you mentioned have chambers the same size as the bore, there is no real advantage.
Dave - In an old T/C 50-cal rifle I had, the bottom of their patent breech was indeed rounded, as you can see from the shape of the special "breech scraping tool" that T/C sold as a cleaning accessory. That tool measures 0.350" in diameter. Thoughts on that size in relation to the 50-cal bore?

Breech.jpg


Other - A long time ago I had I worked on a Traditions flintlock for a friend, and it too had a patent breech, also 50-cal and the T/C tool wouldn't fit. That breech was also rounded and was about 5/16" in size. About 30-years ago I had a Mowrey Plains Rifle built by Bill Mowrey, 2-digit s/n, and that patent breech was 3/16" in diameter as I recall. I use to make single-edge or fly-cutting scraping tools to fit these odd breech sizes, out of brass; goes fairly easy with dykem on the end, filing away where it was wiped off by the breech design.

Safety - Now I always presumed that the reason the imported rifles (and maybe even T/C?) used the patent breech design was for an additional safety factor, to allow for a longer breech plug ... ? I can see that being the case in a modern production environment, versus individually fitting and clocking a typical breech plug.

Cheers and tight groups all!
 
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geco16ga

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Henry Nock gets some credit for "inventing" the Patent breech. He was English and there was a tremendous amount of research during his era for improving the weapons of the day. His patent should be online somewhere which should explain his reasoning. I can't find the site now but I have come across it before which lists British patents.
 
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In this post here, discussing Patent Breeches, the late (and sorely missed 😢 ...) Zonie opined this posit:

"The chambered breech is easy to make which explains why almost all of the Italian made muzzleloading rifles on the market use it."

Link =
NOCKS-BREECH.jpg


Henry Nock was granted a patent in April, 1757, for his clever "false breech", which improved ignition and increased velocity in flint guns. Similar to a modern Diesel "pre-ignition chamber", later percussion breeches were modeled after his design.

Nock_1.jpg
 
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There are probably patent documents somewhere that explain in detail what they supposedly improve upon.
The original motivation for it was to improve ignition. From TOW's description of the diagram in the previous posting above:
" Henry Nock was granted a patent in April, 1757, for his clever "false breech", which improved ignition and increased velocity in flint guns. Similar to a modern Diesel "pre-ignition chamber", later percussion breeches were modeled after his design. "
 
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Modern manufacturers are looking for ways to simplify the manufacturing process. All the previous discussions refer to the improvement of ignition benefits of a chambered breech. In any event, the modern application of a chambered breech allows for the design of a breech plug that can be designed for a flint lock and a design for a cap lock that will fit into one threaded barrel blank. There is only the need for one inventory source for a barrel supply so when the order comes in for a flint lock, any barrel can be used from inventory and no additional manufacturing step is required to drill a touch hole. If the breech plug is to be used in rifles of several calibers, the modern chambered breech is drilled for the smallest caliber barrel. Once again reducing inventory parts control and simplifying the manufacturing process. Any modern benefit to the firing of the gun is a kind of an intended consequence in addition to the simplification of manufacturing.
 

hanshi

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I've owned and relied on several guns with patent breeches over the years and still have one that's a favorite. In all that time I never had any problem that could be traced back to the patent breech. They all worked extremely well and were reliable. But in chronographing velocities in PB and flat breech barrels of the same length there were no significant differences between the two. Despite the fact I was very satisfied with the PB performance, IMHO the patent breech is a failed solution to a nonexistent problem.
 
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Hi Flint62,
The TC might work well depending on how much of the charge the chamber holds. If you look at Nock's actual patent, his antechamber to produce the blast igniting the main charge is pretty small so most of the total powder charge in the barrel is being ignited by the central blast from the antechamber.

Recessed breeches with powder chambers predate percussion and conical bullets by many years.

dave
 
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Despite the fact I was very satisfied with the PB performance, IMHO the patent breech is a failed solution to a nonexistent problem.
I don't have any experience on which to make a pronouncement on this issue, but I'm inclined to agree with your assessment just on fundamental engineering grounds.

The only thing that bothers me about a patent breech is how to clean, dry, and protect it from rust. I suspect this isn't a big problem on larger caliber guns, but on the .32 Crockett I find it to be something of a frustrating pain since the breech seems to be about .20 cal in diameter. This means that I have to resort to my Dewey .20 cal cleaning rod with its 5/40 attachment threading, or some Rube Goldberg-like approach of screwing a Q-tip into my 10/32 brass range rod. Nothing else seems to go into that patent breech. 😡
 

52Bore

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I believe, Nock’s patent breech was also when he introduced hook breeches & tangs… which maybe even moreso the idea than pressure?
 
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Hi,
Hook breeches and tangs go back well before Nock was even in diapers. English rifles and fowlers used them as early as the 1730s. Hook breeches, more traditionally called "false", "break off", and "standing" breeches were designed along with barrel keys, rather than pins, to allow the barrel to be removed easily for cleaning. ,

dave
 

dgracia

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Why do most of the factory guns use the patent breech design ? Seems like extra steps needed to produce a part compared to a flat faced plug. Is there some benefit to this design ? Just curious. -Thanks
It is supposed to give you better ignition because the smaller chamber ignites from the side as in a normal breech, but the flash from that lights the very center of the main charge instead of the side of it, supposedly given a better balanced burn with more even pressure.

This is sort of like the old Honda CVCC (Convex Vortex Combustion Chamber) engines in the 70's where a smaller combustion chamber exited into the main cylinder chamber. A rich fuel mix would be ignited in the small chamber forcing a really hot flash into the main part of the cylinder which had a much leaner mixture in it. Result was a much more complete burn yielding better performance, gas mileage, and less pollution without the need for a catalytic converter. So that Patent Breech was also supposed to give a more complete and even burn with better performance from your rifle.

But there are real problems with that breech that you don't experience with a flat back wall in a regular breech. I have two longrifles. One is the Traditions Pennsylvania Longrifle, which has a Patent-breech style of breech, and the other is an Early Lancaster with the "normal" breech. With a normal breech if you get a flash in the pan, the first thing you do is pick the vent and then it usually fires just fine on the next try.

With a patent breech or at least that style of breech, if you are really lucky, that might also work. HOWEVER if some crud from your previous shot or perhaps from some sloppy cleaning the last time you fired it got into the channel coming into the main chamber, you're done shooting until you clean your rifle. "Wait a minute. Don't shoot at me. I have a clogged patent-breech and I have to clear it before my rifle will fire again."

Of course we don't actually have lines of people trying to kill us from across the field now days, but if you are hunting and you have a flash in the pan, how long do you think you're quarry is going to stand there and be a target for you? Usually that "perfect shot" is a fleeting experience and you can thank Henry Nock for your rifle's temperamental performance.

If you're in a reenactment and your rifle or musket fails to fire 3-times in a row, you are expected to become a casualty on the next enemy volley. Down on the ground you go and that's the last you'll fire your rifle today. "Maybe if I clean it really well, I won't have that problem tomorrow." Actually, YES, maybe if you clean it really well you won't have the problem next time.

I found that cleaning my Traditions with "hydraulic pressure" made the biggest difference in reliability with the Patent Breech style of breech. You don't need any special equipment to do this. What I do is remove my lock and then pour about 2" to 4" of MAP down the barrel using a toothpick or twig in the vent to keep it from running out. I then stand it up against a tree so the breech soaks in the MAP while I clean the lock. You can use regular old water if you'd like, it works just fine.

After cleaning and oiling the lock but before mounting it back onto stock, I will wet a patch and start pushing it leisurely down the barrel of my rifle. You will start to feel resistance as your patch contacts liquid. I'll push it a little bit more to get a little more resistance and then quickly reach down and remove the toothpick or twig from the vent and ram the ramrod down the rest of the way vigorously. This will shoot about a 6-foot long stream of black gunk out of your firelock. Be careful where you point the vent because that black gunk really stains (I still have a stain on a corner of my tent from about 2004).

I'll typically run two more wet patches down or maybe three before the patches really come back clean. Then I'll run a dry patch down followed by an oiled patch (dampened with oil but not dripping). Finally I'll re-attach the lock and wipe a little oil on the outside of the barrel. I actually use that same method with my regular breech rifle too just because it just cleans really well. But it makes a big difference in performance with the Patent Breech-style rifles.

My Traditions rifle with it's patent-style breech is also pretty particular on how I load the pan to get it to work reliably. The lock on it is a small lock, commonly found on pistols. The pan is situated well with the vent centered over the pan, half in and half out of the pan. To get it to fire reliably I need to fill it only half full, close the pan, and then give a quick flick of the wrist to the right. If you open the pan at this point you will see the powder is banked against the outside wall of the pan with an empty space between the powder and the vent hole. When loaded this way, a misfire is a very rare thing. It will quite reliably fire.

Now my Early Lancaster rifle uses a Queen Anne lock by L&R. It is a much larger lock and it doesn't care if I fill it partly full, bank it to the right or left, fill it full up or have excess powder fall out of the pan when I close the frizzen. It just always goes off!. Of course, it's a much bigger lock with a much larger pan, but it also has a much shorter path to the main charge. Personally, I prefer the simpler breech. I'm sure the smaller lock on the Traditions rifle contributes a lot to its temperamentality.
 
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