Odd ignition idea


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AbitNutz
January 9, 2011, 11:35 PM
Ok, this is entirely off the wall but...

I read sometime back about experimenting with front ignition. He took a brass rifle cartridge and drilled out and threaded the primer pocket and then screwed in a brass tube with some cross drilled vent holes toward the front. He put a slot in the very front of the tube so he could use a straight edge screwdriver to install and remove it.

Since C&B revolver cylinders are already threaded...I wonder if a brass or even a stainless steel tube could be screwed in.

My ROA's nipple holes are not centered in the chamber. They're offset to the outside. I'm not sure if all C&B revolvers are like that or not. I'm not sure it matters.

The length of the ignition tube would have to be considered very carefully as you wouldn't want to run the chance of the ball or bullet being rammed into it and damaging it.

The tube would take up some powder space. How much I'm not sure or if it matters.

The advantage? Likely none but the cartridge experiment noticed more constant and slightly higher velocities.

What I'm wondering is if it could result in more reliable ignition of black powder substitutes.

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Chawbaccer
January 10, 2011, 11:38 AM
What I'm wondering is if it could result in more reliable ignition of black powder substitutes.

Do you intend to try it and report back to us?

zimmerstutzen
January 10, 2011, 01:49 PM
If I get your meaning, it is like the primer tubes that extend up into the powder charges of larger artillery shells. One shell i have is 4 inches in diameter and two feet long. It has a tube sticking 8 inches up into the shells interior with holes drilled every two inches.

I often wondered about it for black powder guns, but wondered also, in rifles and muskets whether igniiting front and rear of the powder at one time would cause dangerous pressures.

highorder
January 10, 2011, 02:07 PM
The front ignition research I'm familiar with has no vent holes in the stack, and ignites the front of the powder column only. This has most of the powder burning in the case, and was thought to reduce throat erosion accordingly. The most notable side effect of this was drastically hotter spent brass.

This would translate into a hotter steel cylinder, but I don't know how much effect this would actually have in reality. Interesting stuff.

jtscuba02
January 10, 2011, 02:30 PM
I know the old 105mm tank rds have a similar ignition set-up. The newer ones have combustable cases. The only problem I could see is if it wasn't one piece with the nipple, would the pressure from the cap be enough to send it out the barrel? I guess what I'm asking is, would a press fit be enough to hold it even after it warms up from being fired a few times? You would have to clean it often, probably more than just the nipple alone.

Jim Watson
January 10, 2011, 02:51 PM
I can't imagine OKH Duplex Ignition having any noticeable effect in a c&b revolver.
Maybe in a rifle. You could put flash tubes in .45-70 brass and have easy comparison both ways.
It would be the very devil to clean, though.

Look at some of the old Nock patent breech drawings. Ol Henry put a lot of thought into fast ignition with a flintlock and the contours were meant to throw a jet of flame into the main charge.

GCBurner
January 10, 2011, 04:44 PM
The 19th century Dryse Needle Gun used front ignition, where the percussion cap was against the base of the bullet, and the long needle firing pin went all the way through the powder charge to ignite it. Firing pins didn't tend to last very long, and brass cartridges made this obsolete pretty quick. Pinfire cartridges also have the primer in the middle of the powder charge, but don't seem to show any advantage over conventional priming.

AbitNutz
January 10, 2011, 06:58 PM
I apologize if this is getting too weird. I'm just thinking out loud here. This doesn't really seem impossible of overly complicated....and I have an extra cylinder...or two :)

If I were able to drill out the cylinder for a stainless steel tube, thread the cylinder for it and then thread the tube to accept a nipple. I could drill the tube with small holes toward the forward end, pointed toward the center of the chamber. Remember, the ignition/hole/nipple is well offset to the outer edge of the chamber. The idea would be to ignite the powder charge in more than one place at the same time.

I think I would even consider plugging the end of the tube so that the ignition spark could get out but no powder could get in.

If the flash holes were sized so that no black powder or B/P substitute could get in the tube, cleaning would likely not be an issue.

The whole idea is to get better, more consistent ignition. Like I say, it may not be worth it. It may not work at all but it seems like it should.

If the stainless steel tube were same diameter as a nipple and were threaded completely through the back of the cylinder. I would think it would have enough threaded surface area to give great strength.

However, doing it that way, the diameter of the tube would be pretty large in comparison to the chamber. It could take up a fair amount of powder space.

In the article I read where they did this to a rifle cartridge, they had a number of failures where the tube just blew out. No damage was done to the rifle.

If I were to use stainless steel for the tube it would certainly be stronger but if it failed, the cylinder would likely be damaged if the threads were ripped out. If the tube were brass it would be more likely to fail but if it did fail and rip out, I don't think brass could damage the stainless cylinder.
This sounds like a good scenario but if I did this, I would have the very strong/hard nipple threaded into brass, threaded into stainless steel. Failure of the brass tube could result in it ripping out and blowing the nipple out. That doesn't sound like something I would enjoy.

StrawHat
January 11, 2011, 07:46 AM
Make new nipples with the tube as one piece. Thread into the cylinder as normal. No alteration to the cylinder and easy to convert to original if not as sucessful as you had hoped.

The new nipple would look the same as the originals, just having a longer tube going past the threads.

Nicodemus38
January 11, 2011, 10:40 AM
number 9 is the best reasonable way to do the experiment.

however the ignition may ormay not improve. ignition will ultimately depend upon hotness of cap flame and any contamination in the powder charge.

this idea works best with a rifle or musket, etc as that will allow complete cumbustionof the powder charge. thats why the dreyse was so radicial, almost complete combustion of the charge.

on the revolver, youll have the same amount of pressure bleed off from the cylinder gap.

unspellable
January 11, 2011, 08:27 PM
The weak point in this whole idea is that percussion caps provide very weak ignition compared to primers. This not an issue with a conventional cap & ball piece because black powder or black powder substitutes are much easier to ignite than smokeless.

Going up a flash tube you are likely to have less than reliable ignition. Unless you insure the flash tube has powder in it, but this would delay ignition of the main charge and be detrimental to accuracy. (Remember primers and caps use an explosive which is much faster than powder which is merely a propellant.)

The idea has been done with small caliber cartridge rifles using smokeless, but there you have a primer which is much more powerful than a percussion cap.

Now I might be wrong about this, but that's my story and I'm sticking to it until I change my mind.

StrawHat
January 12, 2011, 06:13 AM
Until you try, you will never know. Make one or two cones and see how they compare to the rest of the cylinder.

You should be able to drill the chamber end of a cone and fit a small tube in place with solder.

Pete D.
January 12, 2011, 08:04 AM
I tried front ignition with a large volume BP cartridge, the 577-450. It was an interesting little project but I abandoned it after a few runs with the chronograph. I have the data - somewhere - if I can find it, I'll post it (but don't hold your breath). There was a slight improvement in the SD as compared to cartridges without the tubes. Of course, I was dealing with much larger volumes of BP than a revolver. I suspect that there would be even less effect with smaller charges.
A lot of work for little gain.....kinda fun to do, though. The big PITA with tubed cartridges is depriming them. Ya gotta make a special little tool to fit the tube or ya hafta take the tube out each time.
That last is not an issue with a percussion gun.
If I were to try this idea with a percussion gun, I would drill out the threaded end of a nipple to accept a piece of thinwall 1/8" brass tubing. As there is no real stress on the tube, you do not need a deep hole but you do need a bottoming tap for the next operation. Then I would thread the tube and tap the newly drilled hole in the nipple and screw the two together. Then that unit would screw in as normal.
Pete

45-70 Ranger
January 12, 2011, 02:14 PM
Sounds like an expensive solution to a nonexisting problem. But what the heck, if ya never try, you'll never know right? Sure be a lof of fine machining going on huh?

AbitNutz
January 12, 2011, 02:35 PM
None of this hobby makes sense. I gave up trying to justify any of it years ago.

45-70 Ranger
January 13, 2011, 03:43 PM
Aw, don't worry about me, I love different stuff! Once built an eletronic ignition system for my 1/5th scale Parott 10 pounder cannon. Used old flashbulb filament with a tube that was inserted into the touch hole and grounded to the trunion cap. Had a small battery box and switch to fire it off. It worked great for about 30 shots then the tube was toast. But....it was fun!

Go have fun and don't take my former comment as anything but an old gunsmith thinking of how to machine those tubes and threaded nipples as one piece! I guess I really was thinking out loud...
Wade

ironhead7544
January 13, 2011, 04:54 PM
I heard of some experiments with the 50 BMG and tubes. Picked up about 200 fps. Wasnt considered worth the effort.

Pete D.
January 13, 2011, 05:37 PM
Sounds like an expensive solution ......
Nah. A bottoming tap and a drill and some 1/8" thinwall tubing. That's all you'd need. And a couple of nipples.
Pete

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