venting a caplock?

[JTR]

The Hotshot was designed to keep caps from getting stuck on the nipple after firing, not relieve the compressed air in the flash channel.
 Hungry Horse

I vent the cleanout screw with the idea that as the powder is poured in and the ball rammed home, compressed air is vented out the side and  the lack of back pressure perhaps helps to insure that the powder is free to enter the drum.
JB

  I understood that venting was to allow the backpressure in the barrel to escape so the fire of the cap could get to the powder?
            Turtle

The whole idea of the vent was to keep the cap you were firing to keep from compressing the air under the cap and thus letting the spark go to the main charge without interference.

Okay, it’s been mentioned by several guys so far, but Good lord, how in the world do you build and maintain pressure/back pressure in a non-enclosed cylinder ie, the barrel? I know I went to school a long time ago, but as far as I know that’s still impossible!

So, going on what I think I know, which could be wrong, but if I have this correct, which I think I do, if you load with the hammer at half cock, any pressure you might build while ramming the patched ball down the barrel leaks out through the hole in the nipple. Result = Zero pressure.

If you load with the hammer down on the expended percussion cap, any pressure you might build either leaks out around the expended cap, or, leaks out through the hole in the nipple when you pull the hammer back and remove the expended cap, before putting on a new percussion cap. Result = Zero pressure.

If you load your rifle with a new unfired percussion cap on the nipple with the hammer down on the cap,  Lord help you! Result = Zero brains!

Or, if you load your rifle with a new unfired percussion cap on the nipple with the hammer at half cock or full cock, Lord help you! Result = possibly Zero pressure, and literally Zero brains!

So these are the only ways I could think of that someone might reload a percussion rifle. If one of you guys has a way to build and maintain pressure/back pressure in a vented cylinder, please disclose your secret to me!

Also, the flame not burning through compressed air is a new one on me.

Hot Dog, I can think of lot’s of applications where that could make me a ton of money! But, well, except, if you look at the principle of how an internal combustion engine operates. So, a brief summary for non-engine guys is a fuel (in our case powder in the barrel), is in the presence of compressed air (somehow in our barrel) and is subjected to a spark or flame, (our percussion cap exploding) the fuel/compressed air mixture will burn hotter and faster than the same mixture at atmospheric pressure,,,,,,. So, so much for that million bucks,,,.

I’m sure I must be missing something someplace here, and would be happy to be corrected.

John   

[Daryl]

 

[shifty]

      In response to TOF some need vented Breechs!

[docone]

I have a caplock that was a real cranky to fire rifle. I mean hangfires, no fires, etc.
What I found on my rifle, was right angles on the flame channel, and threading flash inside the channel. Plus the nipple went into the drum too far and was constricting the flame front.
I spent a few minutes smoothing the obstructions, shortened the threaded portion of the nipple, and it was a fast rifle to fire.
The cleanout screw was out too far in the channel, the nipple was too close to the other wall of the drum, plus flash. I also put some lapping compound on a cord and pulled it through the openings.
That really worked. My wife loves the rifle.
Putting powder down the barrel with the cap on the nipple?
 I hope we are smarter than that!

[kutter]

I remember the idea of venting percussions from older Dixie catalogs.
I then read Peter Alexander's explanation of a percussion system being a 'bomb' and needing the venting as a safety valve of sorts. I don't recall if he also layed on the bit about the air inside the flash channel being backed up/compressed and not allowing the cap flash to reach the powder.

All sounds like a solution looking for a problem to solve, but what do I know.
None of my percussion guns over the years were vented and they all worked fine. So did millions of Military Muskets, Rifles and Revolvers.


...The spark from the cap bounces off compressed air inside the breech causing a misfire??,,is that one of the things 'venting' will avoid for you???,,really???

[Hungry Horse]

 I think thee old timers did this to speed up the ignition, and prevent damage when the main charge ignited, and some of the explosion backed up through the flash channel. I had a CVA Mountain Rifle, that burned out its drum, and nipple, in about two years. CVA replaced them, and an old gun builder told me to vent the drum. I did, and shot the gun until the barrel was completely worn out, and never had another burn out. The ignition seemed better as well.
 Of course the best cure for these issues is to switch to shooting a flinter. It worked for me.

            Hungry Horse

[Stoner creek]

Here's how I vented my last cap lock. I removed the lock, put it in a safe place, installed a touch hole liner, bolted a flintlock in. Worked perfectly.
 Sorry boys I couldn't resist.