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Black Powder Rifle Nipple Falures

Discussion in 'Blackpowder' started by MMA1991, Aug 4, 2013.

  1. MMA1991

    MMA1991 Well-Known Member

    Hello from hot steamy SE Louisiana.

    I am in the midst of getting my restored .45 cal FIE Kentucky Long Rifle ready for the range. Here was my original post:


    I replaced the original stock nipple with a Slix Shot nipple with the gas freeing ports on the side. I also installed a nipple flash cup. I had to heat the original nipple with a butane torch in in order to remove it.

    I have not fired the rifle yet and I was wondering if anyone has ever heard of a nipple failing (i.e. blowing out when the rifle is fired) and blowing back in the shooters face? My replacement nipple seats fine but the flash cup does add a spacer to the seating surface between the rifle barrel and the nipple.

    Not sure if this is an issue but worth asking the experts.


  2. 243winxb

    243winxb Well-Known Member

    Not sure that was safe to do?? Depends on how hot the barrel got. .
    http://www.chuckhawks.com/blackpowder_pyrodex.htm I am no expert, wait for more replys.
  3. Doak

    Doak Well-Known Member

    I have seen a nipple blow out of a generic percussion rifle. Nobody got hurt, 'cept for ringing ears.:-D Don't think the mfgr's name is important.

    What's important, regardless of the thread spec's for the nipple, is the fit of the nipple in the threaded nipple hole. Most nipples have 4 or 5 threads that completely engage the nipple hole, and do the holding.

    Ideally, the threaded portion of a bolt (in this case a nipple) should be as long as the diameter of the bolt. So a 1/4"x28 should have at least 1/4" of threads. M6 x 0.75 should have at least 6mm of threads, etc. Most nipples I've seen, don't quite meet this industry standard. They are usually close enuff. Oddly enuff, making the threaded portion longer doesn't make the assembly stronger.

    Screw the nipple ~ 3/4ths into the nipple hole, & wiggle the nipple w/your fingers. If it doesn't wiggle more than a very little bit...it'll prolly hold just fine.

    If it wiggles around alot, like it feels way too loose, ya prolly gotta a candidate for a possible blowout.

    I think flash cups, under the nipple, are a solution to a problem that doesn't exist. The flash cup, in the hammer face, is there to deflect fire & shrapnel downward, away from the shooter's face. The "snail" & the "fence", shaped into the breech plug, under the nipple, provide a route for the downward shrapnel to follow. Sometimes it's a drum, in a converted flinter.

    Placing an additional flashcup under the nipple, redirects the fire & shrapnel back upward, toward the shooter's face. Why would we want to do that?

    Kindest Regards,
  4. Steel Horse Rider

    Steel Horse Rider Well-Known Member

    If I remember correctly from Tool and Die Maker school some 40 years ago maximum thread strength is 1.5 times the diameter for a fine thread. Fine threads have better shear strength than coarse threads.
  5. BHP FAN

    BHP FAN Well-Known Member

    flash cups keep the wood near the nipple from getting scorched, and the blue or brown on the metal in good shape. if the bottom of the cup is too thick, you can always dress it with a file. just don't take off too much metal, or you'll find the hole has become too large.
  6. MMA1991

    MMA1991 Well-Known Member

    Retapping Nipple recess

    Yup....I checked the nipple at 3/4 insertion into nipple hole as recommended below and it wiggles more than I like.

    I put a lot of sweat equity into this gun and it looks fine and I am dying to make some smoke....but am hesitant to do so if the nipple may fail upon firing.

    I visually inspected the threads inside the nipple hole and there is a 1/16 inch section where the threads are gone and only 2 threads remain. :banghead:

    The upper thread is fairly worn all the way round the top of the hole to boot. Both must have happened when I heated the seized nipple to remove/loosen it after purchasing this rifle in a consignment shop. :cuss:

    The only thing I can think of to make this a rifle a safe shooter is to get the nipple hole retapped at a slightly larger size to reconstruct the threads 100%. Is this feasible or am in the land of pony rides and balloons? Any idea what size I should retap the hole to and where I could find nipples to fit? :confused:
  7. Snaggletooth

    Snaggletooth Well-Known Member

    I would get the retag done and a larger nipple. If anything can go wrong.......
  8. BowerR64

    BowerR64 Well-Known Member

    Why do you usually want to replace the nipples? I understand a dry fire, or event a clogged nipple but what other problems do they have that i should look for?
  9. 243winxb

    243winxb Well-Known Member

  10. RonSC

    RonSC Well-Known Member

    In most cases anything greater than one diameter (of fastener) engagement is wasted. A simpler way to look at it is to inspect the thickness of a nut for a given fastener and you'll find that they are generally only 70-80 percent of the fastener diameter. This of course applies only if optimum fit is achieved.

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