New Breech Plugs for old 1970's vintage H&R .58 Huntsman

Discussion in 'Blackpowder' started by Snidely70431, Apr 3, 2021.

  1. Snidely70431

    Snidely70431 Member

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    A couple of months ago i picked up an old 1970's vintage H&R .58 Huntsman muzzleloader. I finally found a couple of boxes of .58 (.575, actually) round ball ammunition for it at Sportsman's Warehouse, so I decided I had enough to waste a few seeing how it shot, so I made a new breech plug to fit it, this one to take .38 Special or .357 Magnum cartridges instead of 209 shot shell primers. Eventually, I will make one to take .44 S&W Special or .44 Magnum cartridges, and then I will have a muzzleloader that I will be able to shoot as long as I have small or large pistol or rifle primers, or 209 shot shell primers. Right now, with the current primer shortage, having that sort of flexibility is, to me, comforting. BTW, rifle and pistol primers, in my experience, will function in either rifles or pistol cartridges. Pistol primers just won't take high pressures and there may be ignition issues - not an issue in a muzzleloader.

    I know there are some people who will quibble about the old H&R breech plug being unsafe because of the possibility that, in the event of a hang fire, a person could open the breech prematurely and have the BP blow out but, 1) I have never had a hang fire on any firearm using any sort of primer and 2) If I do have a hang fire, I will not open the breech for a while. Sort of like the old joke about the guy who goes to the doctor and says his face hurts, but only when he smiles. Doctor says, "Don't smile."

    upload_2021-4-3_2-50-5.jpeg

    upload_2021-4-3_2-50-40.jpeg

    upload_2021-4-3_2-51-17.jpeg

    In all these pictures the original breech plug is on the right, the new one is on the left.

    The remnant threads on the new plug are the result of there being threads on the scrap steel out of which I made the plug, not of any intent. The O-ring on the new plug is smaller than that on the original because it was what I had. If I can find larger O-rings I may alter the groove to use them, or not. From looking at the plugs, the O-ring probably serves the purpose of holding the plug in the barrel, not to stop leakage, but that is a guess. It may do both.
     
  2. gobsauce

    gobsauce Member

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    Maybe I'm misunderstanding, so I'll bite the bullet and ask.

    Do you just put a primer, or a shell casing with the primer?
     
  3. Snidely70431

    Snidely70431 Member

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    The cartridge is primed, as usual. The primed cartridge is inserted in the breech block. The breech is closed. Propellant is put into the muzzle. A projectile is inserted into the muzzle, in this case a patched round ball. The rifle is now ready to fire.
     
  4. Malachi Leviticus Blue

    Malachi Leviticus Blue Member

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    I wouldn't be thrilled with the idea of priming first then loading from the muzzle.
     
  5. Snidely70431

    Snidely70431 Member

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    The H&R Huntsman is the same action H&R used for its cartridge shotguns and rifles. Have you ever heard of an H&R shotgun or rifle firing without cocking the hammer? IMHO, just another quibble by another quibbler.
     
  6. Jackrabbit1957

    Jackrabbit1957 Member

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    He may be referring to dieseling, a condition that rarely happens due to ramming a patched ball fast enough to compress air hot enough to ignite the powder charge. I have doubts on that but I guess it can happen.
     
  7. Snidely70431

    Snidely70431 Member

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    I have never heard of that happening, but if it could - about which I am agnostic - it would not matter if there was a primer in back of it or not.
     
  8. Malachi Leviticus Blue

    Malachi Leviticus Blue Member

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    Call me names if you want, but it is nearly universally accepted that the first rule of gun safety is to always keep the muzzle of a gun (especially a loaded gun) pointed in a safe direction.
    Obviously muzzleloaders require you to get in front of the muzzle, but most folks do that without a cap or primer in place and prime last when their body parts are out of the way.
    I'm still not thrilled with the idea of getting myself in front of the muzzle of a primed and loaded gun.

    I didn't expect that to be a controversial observation, but to each his own.
     
  9. noelf2

    noelf2 Member

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    I have several H&R break barrel rifles and shotguns. Most have a transfer bar safety. Does the huntsman have a transfer bar safety? If not, I don't suppose I would be comfortable meddling around the muzzle with a primer kissing the hammer either. But hey, that's just me.
     
  10. gobsauce

    gobsauce Member

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    So is it a complete cartridge ? With bullet and powder? Aside from the black powder and patch & ball.
     
  11. Snidely70431

    Snidely70431 Member

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    The old Huntsman does not have a transfer bar per se, but there is a mechanism that prevents the firing pin from protruding past the back of the receiver unless the trigger is pulled. Pushing on the hammer without the trigger being pulled causes the firing pin to stop flush with the back of the receiver.
     
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  12. Snidely70431

    Snidely70431 Member

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    No bullet or powder, just the cartridge case and primer.
     
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  13. Snidely70431

    Snidely70431 Member

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    Made some more breech plugs, one for a .41 Remington Magnum and one for the .410 shotshell.

    upload_2021-5-2_10-56-10.jpeg

    The background is a target shot at about 20' with a .410 Winchester 2 1/2" loaded with a half ounce of #8 shot rated at 1300 fps. Picture includes the actual shotshell.

    Also included in the picture is the breech plug I made to take the .410 shotshell (upper right) and a brass .410 fireformed out of a spent .303 British cartridge using 10 grains of Unique, an overpowder wad of one square of TP, grits to the bottom of the taper, and paraffin wax to the top of the case. Credit to Ed Harris https://www.grantcunningham.com/2014/07/ed-harris-how-to-make-and-load-all-brass-410-shotshells/. You would undoubtedly get better results firing off the round in an actual .410 shotgun, but it worked for my purposes.

    The empty .410 shell holds about 43 grains of Pyrodex, the brass fireformed .303 brass case about 40 grains, with room for an overpowder wad to hold the powder in the case.

    If you are nervous about loading a ball from the muzzle onto powder and a primer, the ball can be seated and then the loaded cartridge case put into the breech plug, but you are limited to the capacity of the case.
     
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  14. TheOutlawKid

    TheOutlawKid Member

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    Sir, do you make these breech plugs yourself?
     
  15. Snidely70431

    Snidely70431 Member

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    Sure. All it takes is a lathe and some drills and reamers. And time.
     
  16. TheOutlawKid

    TheOutlawKid Member

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    I have no lathe or reamers lol. Very talented sir. Keep up the great work!
     
  17. Snidely70431

    Snidely70431 Member

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    Thanks for the encouragement.
     
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