Flash hole position on originals?

[Jakob]

So, I'm doing a fair amount of studying as I'm waiting for parts and particularly to the lock position vs wrist proportions. I'm primarily looking at Jaegers, so I'm not sure how much of that carries over to the US guns, but..
It appears to me that the breech plugs were much shallower, allowing for the locks to be set further back?
Or did they cut grooves into the breech plug. (And if so, how do you deal with fouling?).
On some of them the rear of the pan is in line with the rear of barrel.

[archer829]

Great question!  I don’t have an answer for you, but my guess is that the plugs were not as deep as our modern ones, due to liability issues.  I’ll be interested to see what you find out from the experts!

That being said, the gun in your picture looks amazing!  What is that, and do you have more pictures?

Thanks!
Jeff

[Eric Kettenburg]

American guns frequently have fairly shallow breeches and a pretty good proportion make use of notched plugs.  Not all line up the pan fence with the rear of the barrel though - they're all over the place.  Also it's my opinion that when the pan was pushed forward, it was not common to taper the wood down to fill the gap; it was still typically cut fairly square at the breech.

I have not worked on as many Euro guns as some, but I have seen a few German guns now with longer threaded breeches and the vent was drilled through the breech threads into a bore-size round-bottomed chamber inside the long plug.  The vent liner, usually gold, was only in the barrel, so the plug could be removed without shearing the liner.  Hope this makes sense.

[Eric Kettenburg]

Here are a couple of photos - this is what I have seen on a few German guns of the mid 1750s, those that I've yanked the breech.  I have no idea how common this was but it does work very well - I've shot them quite a bit.

I have never seen this on an American rifle.

[Jakob]

That being said, the gun in your picture looks amazing!  What is that, and do you have more pictures?

It was the most convenient example in my 'library'

https://www.bolk-antiques.nl/inventory/long-guns/a-very-nice-antique-18th-century-swiss-flintlock-rifle-by-albrecht-wagner-in-bern-caliber-14-mm-smooth-length-135-cm-in-very-good-condition-price-2-750-euro-2028814

Here are a couple of photos - this is what I have seen on a few German guns of the mid 1750s, those that I've yanked the breech.  I have no idea how common this was but it does work very well - I've shot them quite a bit.

Thanks for that! The breech plug seems quite long too. I'll assume that cutting into your breech is in general ill-advised, so I'll make do with what I have now, but it really caught my eye today and was curious.

[alacran]

I have studied Wolfe's jaeger book extensively. Mind you there are only about 48 original guns in it. Some of the numbered entries have more than one gun in them. Some have the wood tapered forward to fill the gap and some do not. There doesn't seem to be a correlation as to whether it was early 18th century or later 18th century thing.
Same can be said of the touch hole itself, of the ones that are shown, they are all over the place.

[Goo]

I was trained to place the back of the flash pan even with the very breech end of the barrel. This rule depends on a couple things length of the breech plug and the width of the flash pan.  On many originals the breech plugs were much shorter, today most of us do not feel comfortable shooting 3/8" breech plug.    the touch hole needs be as far back as you can get it even if you need to notch the face of the breech plug.  On locks with wide flash pans you can set them up so the flash guard is even with the breech.  With narrow pans and a 1/2" breech plug you cant get this configuration  unless the Breech plug is altered by dishing it out and drilling through the threads 0r if you use a 3/8" breech plug.  Most people dont mind the flash pan not lining up with the end of the barrel for me I prefer they line up.         

[Bob Roller]

 have wondered about the chambered plug with a hole thru the threads,It can't blow up or blow out.Several years ago I thought of buying a replica Harpers Ferry 1803 and when I removed the breech plug it made about 2 turns and fell on the floor.It was 3/8" of threads and a slow lock as well.I have no memory of long breech plug thread on any American antique gun and no surviving powder measures that could be considered as extreme.The first absurd loads I remember were in the 1960's when some shot well over 100 grains in a round ball rifle.
How beneficial that was is open to question.Tom Dawson's experiments showed a 13" drop at 130 yard with a 54 caliber round ball from a Bill Large barrel and 150 grins of 3fg DuPont.I think it was Herb on this forum that said the Bridger Hawken (I think) had a measure with it that held 50 grains and if more was needed then refill the measure.My own tests at 150 yards gave the same results as Tom Dawson's,We didn't worry about a blown up gun then and mostly still don't.I wonder if some of these heavy loads are attempts to make a "magnum" when using a muzzle loader and relying on "modern "barrels to keep them out of the ER or worse.A round ball has no sectional density and sheds velocity quickly.Tests have shown a .451 long range rifle still has a good percentage of muzzle velocity even at 1000 yards. with a 550 grain
bullet.I doubt if a .451 round ball would make it to 1000 yards.
Bob Roller

[Dphariss]

I sometimes use the vent through the breech plug. It allows placing the  lock’s fence at the breech. Which makes for a better looking gun. IMO.  English locks are usually longer from fence to pan than Germanic locks 
The cupped breech, I have been told will provide increased velocity over a flat breech. Never tested it.
If done correctly with a shop made vent liner all threads are sealed from powder gases.
 
These show how I have done it and how the English did it on some guns. Showing a Nock breech and a simple breech. I have seen at least one English pistol done in the same way Eric’s photo shows. But with shorter threads.
Also remember that the breech threads were often a very low tolerance fit compared to modern “tolerance” designed to make interchangeable parts. And its difficult to make a shoulder seal when the bore is simply tapped for the breech threads as was sometimes done even in rifles at least in America. But the breechplug fills all the threads and the tap cut full depth threads to the end or very nearly. At least in my limited research. Modern taps need to be ground back significantly to do this and there is risk of breaking off the end “tooth”. Also threading to the very back of the breechplug is not really possible in mass produced parts and even a modern threading die will need to be ground back somewhat to achieve this.
I have an American breech plug from an original (relic) welded barrel in the shop that is short and has only 4 (IIRC) large round profile threads.

[Craig Wilcox]

Like the design of both XXX and XXXI.  Either would be very efficient, and XXXI even allows a "clean-out plug".  I do wonder how often that rear chamber would be cleaned, however, as the barrel would have to be removed for thorough cleaning.

Two sizes of wipers and brushes?

With the possible increase in velocity (love to test using a chronograph!), I do think this would be worth the extra cleaning efforts.

[Eric Kettenburg]

That top drawing is exactly how I have seen it done on some German guns and as the photos I posted, except the vent liner does not go through the plug so that the plug can be easily removed.  The down side to that, though, is that it may allow some leakage into the threads.  Have had no problem removing them or seen much corrosion otoh.

[Daryl]

Dan's top photo is identical to the Blissett shotgun breech and stubb barrel I have. I was going to line it but never got around to it.

[D. Taylor Sapergia]

None of these breech designs is a problem if you remove the barrel and clean it in a vessel of tepid water with a tight fitting patch and jag.  Water flushes out all of the fowling so smaller brushes and wipers are not required.  If however you simply wipe your bores "clean" with the barrel still in the stock, all bets are off with regards to how clean the breech gets. 
I submit that many of you who have trouble loading a .005" smaller ball and a .020" patch do not use a regime that gets your barrels clean, and that oxidation in your bores over a period of time frosts the bore making loading difficult...not to mention what that does to accuracy.  As I said at the beginning of that sentence, that is my submission, and if I am in error, I welcome enlightenment.

[Dphariss]

That top drawing is exactly how I have seen it done on some German guns and as the photos I posted, except the vent liner does not go through the plug so that the plug can be easily removed.  The down side to that, though, is that it may allow some leakage into the threads.  Have had no problem removing them or seen much corrosion otoh.

have wondered about the chambered plug with a hole thru the threads,It can't blow up or blow out.Several years ago I thought of buying a replica Harpers Ferry 1803 and when I removed the breech plug it made about 2 turns and fell on the floor.It was 3/8" of threads and a slow lock as well.I have no memory of long breech plug thread on any American antique gun and no surviving powder measures that could be considered as extreme.The first absurd loads I remember were in the 1960's when some shot well over 100 grains in a round ball rifle.
How beneficial that was is open to question.Tom Dawson's experiments showed a 13" drop at 130 yard with a 54 caliber round ball from a Bill Large barrel and 150 grins of 3fg DuPont.I think it was Herb on this forum that said the Bridger Hawken (I think) had a measure with it that held 50 grains and if more was needed then refill the measure.My own tests at 150 yards gave the same results as Tom Dawson's,We didn't worry about a blown up gun then and mostly still don't.I wonder if some of these heavy loads are attempts to make a "magnum" when using a muzzle loader and relying on "modern "barrels to keep them out of the ER or worse.A round ball has no sectional density and sheds velocity quickly.Tests have shown a .451 long range rifle still has a good percentage of muzzle velocity even at 1000 yards. with a 550 grain
bullet.I doubt if a .451 round ball would make it to 1000 yards.
Bob Roller

In the West trajectory was more important and velocity gives flatter trajectories. And not all rifles shoot well with loads that are too light. But this might be a result of the modern barrels having slower twists. About 1/2 ball weight of powder or a little less will give a 50-54 caliber all the velocity it needs for a deer sized point blank range of 120-130 yards if sighted for about 1” high at 100. But it falls rapidly past 100 yards. Now a RB launched at 1200-1300 will kill most critters to 100 yards or so. But the trajectory is going to be a lot higher and this makes it harder to make kill zone hits at even 100 yards. The light charges uysed by European rifles for the most part resulted in multi leaf rear sights sometime with leaves for 50-75 and 100 or  75-100-125. The average American rifle of 44-50 caliber with a charge around 1/2 ball weight will shoot flat enough that no allowance of range is needed to at least 100 yards.
Col Hanger  reported that the rifles he captured or otherwise examined during the Rev War  gave little recoil with 1/2 ball weight of powder but he wrote that he never found any large bore rifles. Paraphrased he stated that he had seen many hundreds of  American rifles and never saw one larger than 36 balls to the pound. Now we KNOW some were larger. But John Joseph Henry’s comment on the rifle that replaced the one he lost in a stream crossing enroute to Quebec indicate that there were many, the great majority I think, rifles of this time were 50 caliber or less. This also borne out by rifles taken back to England as trophys of  war. The Dickert in both RoCA and the 1st Moravian Gunmaking and the 42 caliber smooth rifle that Col Hanger took back to England also bear this out. There are exceptions but not many are mentioned. Finding any description of American long rifle bore sizes is rare.

[Dphariss]

That top drawing is exactly how I have seen it done on some German guns and as the photos I posted, except the vent liner does not go through the plug so that the plug can be easily removed.  The down side to that, though, is that it may allow some leakage into the threads.  Have had no problem removing them or seen much corrosion otoh.

BP fouling that is dry, <30% humidity or cut off from atmosphere or oiled usually causes no rust or very little.
I always use plenty of water in cleaning BP fouling.
The problem (well one of them) with breeches that are not sealed using modern threads, even if a low tolerance tap is used. Is that oil in the bore can travel down the threads and escape into the stock. The other problem is if its percussion ignition and a certain “replica” powder is used it will aggressively rust steel, wet, dry or oiled. Its bad enough without some hidden fouling trap with one it’s really scary. It can litterally eat its way to the exterior. Having a fouling ring at the face of the breechplug? Rather not even think about it.

[Eric Kettenburg]

The problem (well one of them) with breeches that are not sealed using modern threads, even if a low tolerance tap is used. Is that oil in the bore can travel down the threads and escape into the stock.

Yes I agree, and this is well-illustrated by the large number of old kentuckies with the wood all around the breech area being pretty much 'punky.'  If not gone.  All of the American stuff used fairly coarse threads, with shallow thread depth, and I'm sure very quickly in the rifles' lives, all kinds of $#@* was wicking its way right into the wood surrounding the breech.  This, compounded by oils inside the lock wicking their way into the same area.

We tend to think very long term when building rifles today because for us it is hobby or art - essentially they are luxury items.  I sincerely doubt that in 1770 or 1780 or 1790, any of those guys were thinking 100 years or more down the road.  I strongly suspect the majority were thinking maybe 25 or 35 years down the road at most, basically their (gunmaker and/or customer) working lifetime.

[Darkhorse]

My working career was in the manufacture of aircraft structural components. I did some of all of it. Starting in the machine shops, then Numerical Control, about 10 years as a Tool & Die maker, then I rode a desk in engineering data management.
I listed this background to maybe add some weight to my next statement. First telling by engineers, then toolmakers. After that it's hard to find someone with knowledge on the subject.
"3 full threads deep and maximum strength has been reached."
I personally never tested this, preferring a half inch or so depth.
But if this is true then a breech plug 3/8ths deep is plenty strong enough.
If anybody has ever heard this, positive or negative, please share.

[Dphariss]

To add a little to Darkhorse.
Not a tool and die maker or trained machinist..
However, I can look things up. Some research will, I think show that in any threaded joint that the first 3 threads bear most, it not all the load. We know that the nut side of a nut and bolt connection has enough threads to pull the bolt in two if grossly over torqued. So a threaded portion as long as the nut (in threads) is stronger than the bolt.
Now if we look up the tensile of  a 5/8 or 3/4” mild steel bolt then look at the breech pressure and the square inches of the area subject to pressure we see that there is not that much stress on the threads.
For example a 54 caliber rifled bore with .012” deep grooves gives about a .564 actual bore size (ignoring the lands) if we do the calculation for the area of a circle we find a small faction of a square inch. The online area of a circle calculator will give almost .25 square inches.
So breech thrust compared to the strength of our bolt is pretty low.
HOWEVER. Since we are dealing with human life we need to add a significant safety level. So 1/2” is a decent length. Longer is good of course.
Modern breeching almost never fails, at least that I have heard of.
But there was an interesting article on the Buckskin/Blackpowder Report by a physician circa 1830 who had a patient come to him with headaches and (IIRC) vision problems with his right eye after his rifle burst a few years previous.  In close examination he found a piece of metal showing at the inside corner of the right eye socket. Eventually he extracted a BREECHPLUG for this location and did so without loss of the eye. Apparently when the barrel failed the breech plug was ejected with enough force to conceal itself in the eye socket. I could, if I wanted find the article I guess. But this is a pretty accurate short version.
AND  the threads may not be the weak area. It could be the wall thickness between the threaded recess in the barrel and the outside diameter.  I.E. a 3/4-16 plug in a 15/16” barrel is a bad idea IMO. AND if there is a fouling trap at the face of the plug, plug does not seat against a shoulder, and it has been shot with a highly corrosive “replica powder” then the breech may be significantly weakened.

[Daryl]

I recall that article, Dphar, along with pictures made by the Dr. The breech plug and short tang were a one-piece affair.

[D. Taylor Sapergia]

I have a pair of 15 bore Staudenhauer (Sp?) barrels from which I removed the breech plugs.  I had to make a maple/bondo lined holder for the barrels in order to support them while I used a wrench on the plugs, but they came out nicely.  The threaded journals are only 3/8" long, have very clean sharp threads as do the female threads in the barrels, and some of the case colours still remain.  There was apparently absolutely no gas cutting or fouling trapped in these breeches over the lifetime of their use.  I know that a shotgun barrel is quite another critter compared to a rifle barrel as far as pressure is concerned though.
Dan's comment about oil soaking wood is the primary reason I store all of my firearms on their muzzles.

[Darkhorse]

First a thank you to Dphariss for a little scientific evidence justifying a 3/8 ths long breech plug. That little bit of extra research is more than I've ever considered doing on the subject.
And that post by Taylor concerning how sharp and clean the threads were after years of service only serves to bring to mind other questions I've had in the past.

The methods used to cut the threads on those old rifles were primitive in my opinion. And my opinion/s are based on a limited knowledge of cutting modern threads and then measuring them so they can pass the inspectors all seeing eyes. When cutting, chasing or rolling threads for a USAF aircraft many of these items can cost lives if they fail so the inspection of these items is sometimes very involved and goes beyond, say, class 3A and a thread gage.
Now I have the utmost respect for the work many of the old masters accomplished and I wish I could have seen it being done. So I could attempt to accomplish it myself. I find the machining of the old lock parts to be simply amazing using the tooling and knowledge available to them. I am often fascinated by how smooth these locks work (many of them anyway), most likely this is why when I have a lock problem I will buy an extra part or two, then attempt to fix it myself. In this way I gain knowledge and if lucky a slight improvement.
So to end this I hope I make a little sense and say I think those guys were good. Very good.
And some of you guys are pretty darn sharp yourselves.