Does it matter where the powder is ignited?

Does it matter if the powder is ignited at the rear or at the front of the charge?

Rear is thought more efficient. Thats one reason why the patent preech was designed.

Most today say the rear. Could be. There are several period treatises on the subject and their tests suggest the middle of the powder column or somewhat forward of the breech plug. Using the front of the charge will limit you to a large minimum charge, which will be the only practical difference between front and rear.

Yes, it matters where the powder is ignited. If the ignition point is near the base of the ball, a light charge will put the ball (or bullet) over the touch hole and there will be no ignition. The entry of the flash channel should be at the face of the breech.

I have used a friends matchlock that had a reduced chamber with the touch hole half way along it, the difference was startling felt much more like a modern 12 bore.

Although many feel that starting the ignition at the rear of the powder charge is best, I can give an answer that defends the idea of using a regular side mounted drum thru the wall of the barrel, that feeds the cap flash into the powder charge in the middle.

If the powder is ignited at the rear, it has to burn forward thru the entire length of the charge to fully ignite it.

If the powder charge is ignited somewhere around the middle of it, there will be two flame fronts moving thru the charge. One towards the rear and one towards the front. By doing this, in theory, the entire powder charge will be totally ignited in a shorter period of time, perhaps twice as fast so, the peak pressure of the gas will occur earlier. This in effect, it would create a higher velocity and it should have a more complete burn leaving less powder fouling.

No. I haven't tested it. Yes. This is only theory but, it does give people who need it, something to think about.

I can see this going the way of the ball spin discussion that was a hot topic earlier, at least I believe it was ball spin way too technical for this woodsman, Also I can see ZONIE a rumbling and mumbling around with his slide rule and gravitational pull of the earth charts hunkered down like a wizard scratching his head in deep thought. Wonder if what side of equator your on has anything to with the earth in relation to the sun and such things and the ability to move the burn at a faster or slower rate. Just kidding but this should get interesting. Put on your tin foil hats boys there's information a coming.

I put all mine at the very rear but then I got tired of having to file and smooth the plug some for the liner. My last build, a .62 jaeger, I installed the liner more forward...a few mm. It was no worry on the .62 since my starting load is 90 grains. It shoots amazingly well with every patch ball and charge combo I've tried so far. Fastest ignition in a flint rifle I've ever shot as well....just instant honestly. Neither of these things may be related to touch hole position but I know my next couple builds will be done this way as well.

Perhaps having the charge ignited, at least some distance(ie. 25%-40% of the powder column) off the breech end would help to keep any residue pushed down as the result of swabbing, or residual oil, away from the powder at the flash hole. I’m not sure overall ignition efficiency would affected, or even perceived simply by location of flame entry along the powder column, considering the inherently fast burn rate of black powder. I had a similar experience as martini9 with a flash liner that had the flash hole entry very close, if not just touching the breech-lug. Cutting back the breech plug a bit improved ignition by having the full flame from the flash hole hitting the charge.

On my first rifle (plank build) I was obsessed with having the vent right on the breech face because that is what I had read repeatedly as I learned about gun building, I even had to notch the plug slightly to accommodate the liner.

Not really happy with a notched plug below my formally well sealed breech face I moved the vent liner forward on the rest of my gun builds. They work just fine, I can't really see the benefit of having the vent right on the breech face, perhaps this is another old wives tale that stuck in the minds of many just like "seasoning the bore".

Here is where I put them now. This is a 13/16" barrel.

Zonie said:

in theory

Click to expand...

Yep. Sez it all. Add this subject to WD-40 and others. The discussion can go on forever. History has left guns with all types of breech configurations.

Another question on this subject. I have heard (you know how reliable those sources are) that CW rifle/muskets had deep, Knock style, breeches because this, supposedly, increased recoil and helped assure the soldier shooter knew when his piece went off. Any truth to this?