Recessed crown

Discussion in 'The Gun Builder's Bench' started by theoldredneck, Jun 12, 2019.

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  1. Jun 24, 2019 #21

    SDSmlf

    SDSmlf

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    I believe original ‘coning’ tools were very common and every muzzleloader shooter had one. Today we call the period coning tool a ramrod or wiping stick. I have seen a few original guns that definitely had extensive wear in the bore at the muzzle. Smooth, gradual and even. Some call it coning. Doubt it was put there on purpose by a gunsmith. Have also seen original guns with little wear. Maybe a refresh, or shot little, or maybe a careful owner.

    It would almost seem to me what we call coning is just another modern attempt to mimic natural aging or wear that occurred over time. Here is a photograph of a ‘modern’ muzzleloader bore with maybe a hundred shots through it, loaded and cleaned with the ramrod and no bore guide according to the original owner. Doesn’t believe in bore guides ‘cause they weren’t used in the day’. How long before this becomes a coned bore?
    upload_2019-6-24_13-38-50.jpeg

    For a modern example, one has to look no farther that WWII vintage guns. The folks that shoot these use gauge pins to determine bore wear at the muzzle. You find barrels that are ‘shot out’ to the point of no rifling at the bore, yet an inch or two down, the bore can be in spec. These guns, because of their design are cleaned through the muzzle (with a sectioned metal rod and no muzzle guide). They don’t call this coning. They call it wear and replace the barrel.
     
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  2. Jun 24, 2019 #22

    Artificer

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    SDSmlf,

    The photo in your avatar looks like what causes the most wear on both the muzzle and the touch hole, when good cleaning techniques are used. The superheated gas, left over from the burnt powder that pushes the PRB down the bore, hits the oxygen rich atmosphere and ignites and gives those "fireballs" at both locations on the barrel. Those fireballs burn the touch hole and the muzzle and cause what is usually called "muzzle erosion" at the front of the barrel.

    Though we see the touch holes enlarging and muzzle wear in our muzzle loading barrels with enough rounds fired, we don't see as much as they did in the period, because we are using tougher steel barrels than their dead soft Iron barrels. Their softer Iron barrels required "freshening" much sooner and more often than we ever see with our modern steel barrels. The problem for us is, it is hard to document how much quicker dead soft Iron barrels wore, because no one seems to have recorded the number of rounds fired in a barrel before it needed "refreshed."

    For those who don't know what period "freshening" barrel cutters looked like, please see the following link:
    http://www.flintriflesmith.com/ToolsandTechniques/freshening.htm

    Maybe the best documentation on how much faster their barrels wore is one of the men with Louis and Clark was an Armorer and brought tools to freshen the rifling in their rifles along the way. It was actually recorded he freshened some barrels during the journey.

    Like you and I'm sure others on the forum, we have noticed the erosion on both the muzzles and touch holes of original rifle barrels, but that muzzle erosion is different than what would be left over from modern coning tools.

    Gus
     
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  3. Jun 24, 2019 #23

    SDSmlf

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    Not arguing that flame cutting doesn’t occur at both ends of the barrel, just believe it is minimal at the muzzle at BP pressures with roundballs. The, touchhole, being much smaller, let’s the gas escape at much lower volume, but higher pressure, plus by the time the ball exits the barrel the pressure has dropped dramatically - look at any pressure curve, modern or traditional, they all drop significantly before the bullet leaves the barrel. And just as a discussion point, you mention the gun in my avitar. Likely 80 grains fff under a 58 cal round ball in a 26” barrel. The area of the touchhole (.078”) is less than 2% of the area of the muzzle (58 cal). Higher pressure, smaller escape hole, the touchhole should and does erode much faster. But not as fast as percussion nipples wear when shooting heavy conicals where the open areas in the nipple (.028”) is only 0.5% of the bore (45 cal) area. Can open those up in less than 50 shots.

    The guy that mentored me when I was first starting out years ago had an original high end target muzzleloader that some relative used to compete with back in the day. The bore had never been touched from the day it was made (so I was told). It had a false muzzle that as I remember had sort of a funnel thing going on. Never really thought about it, but possible ramrod wear? The muzzle of the gun was square and sharp at the bore. No apparent chamfer, let alone wear of any kind that I remember. The gun would hang in there accuracy wise with the modern guns when I last saw it 30 years ago. Who knows how many thousands of shots that barrel and muzzle saw during its existence.
     
  4. Jun 25, 2019 #24

    Artificer

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    SDSmlf,

    I spent most of my 26 Career in the Corps building, maintaining and repairing NM rifles that had to be cleaned from the muzzle. The only reason I mention that is because along the way we learned quite a few things about muzzle damage from cleaning rods, some of which does transfer directly to ML barrels.

    First, we really can't use some muzzle wear information from WWII semi auto rifles, that have to be cleaned from the muzzle, as indicative of what happens in a ML barrel. This because even when those rifles were fired with sand or dirt in the bore that caused lapping in the barrel, it has been proven it was the high rate of fire in combat that caused more damage to the muzzles than anything else. I'm not a mechanical engineer, so please allow a layman's explanation that when barrels are already hot from fast firing, subsequent rounds fired keep the barrel temps high enough to do more damage to them than done in slow fire or even timed/rapid fire of matches.

    Over the years, we tried almost every kind of material that cleaning rods were made from and/or were coated with. Though we did not use wood rods, we found that plastic coated rods would pick up and embed contaminants that would act as a lapping compound and do the most damage to the muzzle. Brass rods also did it, but not as bad as plastic coated rods. We found one piece hardened stainless steel rods with muzzle protectors did the least damage, because contaminants would not easily embed in the hardened surface of the rod. We also taught the shooters to wipe their rods clean after each time in and out of the bore.

    Of course with ML barrels in the period, they used and many of us use wooden ramrods and those rods will pick up and embed sand/grit/dirt faster than any other material ramrods are made from. In turn, the embedded contaminants act as a lapping compound and because ramrods are bent more near the muzzle while loading, they do the most "lapping" damage near the muzzle.

    What many of us also don't think of is that oiled/greased and to a lesser degree spit patches will also pick up foreign contaminants that will act as a lapping compound in the barrels.

    There were basically two kinds of special devices used to start the patched round balls in target rifles of the percussion period. The first fit over the end of the muzzle and because of the precision machining of the fit to the barrel diameter and short starter rod in the device, the short starter rod centered the patch ball and did not normally touch the bore. The more advanced models had a false muzzle that was actually made from the barrel and then cut off to form a separate piece that aligned with the barrel using pins when loading. They would also use the first kind of short starter with false muzzles so the starter rods did not touch the bore at all. Of course, most of us don't have either of these devices for our ML barrels. If there is a cap on the muzzle end of the stock, as found on many of our reproductions, it is usually too close to the muzzle to allow a device that centers around the barrel diameter.

    Those of us who were or are dedicated target shooters will fire more rounds in a shooting season than many of the "old timers" did in a number of years. Even though you are correct "flame cutting" is not as great with ML's as modern rifles, there is still flame cutting going on at the muzzle with each round fired. When we fire more rounds, it is going to cause more muzzle wear than if we only fired a few rounds each year during hunting season, as some modern ML shooters do.

    For those of us who were/are target shooters, I definitely agree a muzzle protector that keeps the rod centered in the bore is useful to keep down on muzzle wear, even though our barrels are tougher steel than the soft Iron barrels they used for most of the period of this forum. I also agree that a funnel shaped bore protector that goes into the bore and aligns the cleaning rod is a good idea for cleaning, to help keep down muzzle wear.

    Gus

    BTW, when I first got involved as the Armorer to the U.S. International Muzzle Loading Team, I was a bit surprised at another device they used. Many of the shooters used a brass or copper funnel soldered to a long brass or copper tube that fit inside the bore and went all the way to the breech end in the barrel. The idea was their powder charge would then not get mixed with fired residue on the way down the bore and thus cause more uniform/consistent powder ignition/burning and thus slightly better accuracy. I had never seen them at the Nationals at Friendship, BUT I was a primitive shooter and never shot on the ranges that allowed such things there. So as soon as I saw those devices, I realized the advantage of using them on ranges and types of matches that allowed them.

    Gus
     
    Last edited: Jun 25, 2019
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  5. Jun 25, 2019 #25

    45man

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    I agree rod wear is the culprit. Barrels were never coned except a false muzzle and I have made them, devil to align the rifling.
    Old timers did crown with a hand made ball cutter and a brace and bit. I never used a chatter cutter myself but silver soldered a rod to a ball bearing and did it by hand with abrasives. I polished until I met the grooves only. I still do it with modern guns cut down even though I have a lathe. I do not like to remove a barrel or chuck it. The outside of a barrel might not be true with the bore so you get off side crowns.
    The worst gun I ever tried to make shoot had the easy start muzzle. The inside of a barn was safe from that thing.
    I use steel rods with a brass bore protector I make for each rod. I also use a protector with a wood rod to load. I even have one on my long starters.
     
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  6. Jun 25, 2019 #26

    SDSmlf

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    My exposure to Milsurp guns is limited to the few dozen plus that I own and shoot, nowhere near your experience, a much more statistically significant sampling.

    The point I was attempting to make was that I have seen substantial wear in some Milsurp guns at the muzzle and little or no erosion in the rest of the bore or throat, and speculated that wear at the muzzle was from aggressive cleaning rod use. Similar wear, if found in a muzzleloader bore, could be attributed by some to be the result of intentional coning, not good old fashioned ramrod use wear. Just an opinion based on my limited observations.
     
  7. Jun 26, 2019 #27

    JB67

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    Ramrod wear? REALLY?? From wood ramrods? That defies logic. The rod would wear first, and any ramrod-induced wear would be uneven.

    Coning, or relieving, is a real thing. Here's a page with some good discussion and period examples.

    http://americanlongrifles.org/forum/index.php?topic=47601.0
     
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  8. Jun 26, 2019 #28

    Artificer

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    It is not the wood that wears the bore/crown, it is the sand/grit/foreign matter that gets embedded in the wood ramrods and are abrasive, which acts something like a lapping compound.

    Definitely agree such wear is uneven.

    The link shows the hand filed rounding at the Muzzle we were discussing earlier, though that is not like what is done by modern Coning Tools. Thank you.

    Gus
     
  9. Jun 26, 2019 #29

    JB67

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    Just how much grit can get imbedded in the wood? The barrels would still abraid the wood faster, and the pores wouldn't hold enough to make a difference.

    Some of those pics in my link show barrels that were coned, with the rifling touched up afterwards.

    There are examples elsewhere on the web of relieved barrels that were not done with files. Given that it ranges from a half inch to a couple inches deep, it would not always be readily apparent to casual observation.
     
  10. Jun 26, 2019 #30

    rich pierce

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    I do not believe in rod wear. It does not/cannot happen. Why do I say this? Because I fresh old barrels. I lap old barrels. It is a TON of deliberate, focused work to increase bore size 0.001” by lapping with a lap embedded with 100% abrasive. Force and 600 strokes later, having added abrasive several times, and you might get 0.001”. These myths never die.

    To deepen ONE groove or land by 0.001” on wrought iron barrels by freshing takes a perfectly formed and fitting sharp cutter and 4 passes per groove or land. The first cut takes real muscle unless you have a cross handle on your freshing stick.

    It’s just a fact that the majority of original percussion era barrels are relieved at the muzzle for over an inch by as much as 0.015”. I know because I fresh them. I do not know how it was done but it is nearly universal on percussion rifles. Have you ever seen a picture of an original Leman or Hawken or any other rifle of the period with a perfectly square muzzle with no countersink crown? That barrel has a relieved muzzle or it could not be loaded.
     
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  11. Jun 26, 2019 #31

    jrdavis

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    I think a lot of people on here are loosing sight that we are talking about antique and antique type guns here not how modern guns have changed over time ...
     
  12. Jun 26, 2019 #32

    SDSmlf

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    Rich, nothing like first hand knowledge and real experience to take the sail of a good myth out of the wind. Have been hearing this ramrod bore wear theory/myth since the 1970s and even heard it in Germany when I had the opportunity of shooting some original Jaegers there. Guess if something is repeated often and loudly enough it becomes ‘fact’, dispite the evidence.

    Appreciate your insite. Thank you.
     
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  13. Jun 30, 2019 #33

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