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Thread: Black Powder firearms and muzzle velocity measurement?

  1. #16
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    By the way...

    The rest of theignoring cakes and muffins for the time-being -

    A .36cal BP revolver fires a .380" diameter ball at an average velocity of 800 fps.

    The resultant m/e is 102.5 ft lbs.

    A high velocity .22LR like the CCI Mini-Mag or Stinger, fires a 40gr bullet at ca. 1450 fps.

    The resultant m/e is 186.8 ft lbs.

    So even a .36cal BP revolver has substantially less 'oomph' than a Mini-Mag or Stinger, both of which are common or garden fare in most .22 clubs, especially if there is much shooting of the Ruger 10/22 - a gun that has a particular penchant for these higher-velocity .22 rimfire cartridges.

    This rest of this post has been deleted as it is simply opinion and not really moot.

    tac
    Last edited by tacfoley; 05-11-2014 at 12:21 PM.

  2. #17
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    Quote Originally Posted by severnsider View Post
    I believe that .357 carbine should be permitted (if we consider it to be a c/f pistol calibre) as the max. permitted is .44. The stipulations regarding MV/ME are in the range safety certificate, so MV will have to be measured to ensure that neither criterion is exceeded.
    I'm reading this again.

    There is no 'consider' about it. The .357 Magnum was designed from the get-go as a revolver cartridge back in 1935. Same goes for the .44 Remington Magnum revolver cartridge, designed by Elmer Keith back in 1956.

    NO BP handgun on the planet will equal the velocity of a 158gr .357 Magnum calibre bullet. It is therefore obvious, or should be to anybody who can count up to, including and possibly past the number of fingers on one hand, that shooting the same round from a carbine will produce even higher m/v than from a pistol, due to the increased powder burn time in the longer barrel.

    If the range is cleared for .44 Mag, then very few BP rifles will get near the velocity of THAT, even shooting the lighter than usual 180 or 200gr bullet - as you know, the 'standard' for the .44 Magnum revolver cartridge is a 240gr something or other. As pointed out already by two of us, a ball fired from a .44BP revolver only weighs in at ca. 148gr.

    tac

    PS - among the things that you haven't told us is whether or not the range is indoors or open to the skies.

  3. #18
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    Quote Originally Posted by tacfoley View Post
    I'm reading this again.

    There is no 'consider' about it. The .357 Magnum was designed from the get-go as a revolver cartridge back in 1935. Same goes for the .44 Remington Magnum revolver cartridge, designed by Elmer Keith back in 1956.

    NO BP handgun on the planet will equal the velocity of a 158gr .357 Magnum calibre bullet. It is therefore obvious, or should be to anybody who can count up to, including and possibly past the number of fingers on one hand, that shooting the same round from a carbine will produce even higher m/v than from a pistol, due to the increased powder burn time in the longer barrel.

    If the range is cleared for .44 Mag, then very few BP rifles will get near the velocity of THAT, even shooting the lighter than usual 180 or 200gr bullet - as you know, the 'standard' for the .44 Magnum revolver cartridge is a 240gr something or other. As pointed out already by two of us, a ball fired from a .44BP revolver only weighs in at ca. 148gr.

    tac

    PS - among the things that you haven't told us is whether or not the range is indoors or open to the skies.
    Well, hello again! I'll hang onto the cream buns for a while, but thanks again for this latest info. It's a 50m outdoor range. I have PM'd you as I don't think it would be appropriate to identify the place on here

  4. #19
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    Quote Originally Posted by severnsider View Post
    Well, hello again! I'll hang onto the cream buns for a while, but thanks again for this latest info. It's a 50m outdoor range. I have PM'd you as I don't think it would be appropriate to identify the place on here
    Yo Severnsider - thanks for the PM, see my réponse[s].

    I'm sure that between the three of of us [you, turnup and me] that we can sort this out.

    Best

    tac

    PS - double-chocolate chip muffins and 8" individual LMP are more my style, TBH.
    Last edited by tacfoley; 05-11-2014 at 02:14 PM.

  5. #20
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    Thinking a little more about energy with BP, it occurred to me that a given weight of BP will release a reasonably predictable amount of energy when fired. I know that BPs are not all the same, but chemically they are very similar and the same chemistry and physics will apply. Could this help us to estimate how to stay within the OPs range limits?

    So, I discover that 1 kg of BP contains about 3MJ of energy, which is 2.2M ft-lbs.

    Quick calculation shows this to be just about 143 ft-lbs per grain.

    Much more than I was expecting!


    ...and not at all helpful.

    Clearly firearms are a very inefficient way of converting BP chemical energy into projectile kinetic energy.

    Another approach is needed.
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  6. #21
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    Providing that the shooters are not shooting a BP projectile faster than 1500 fps [the SAAMI .44 Magnum 240gr maximum velocity] there should be no problems. Since the British shooters tend not to have rifles of the Long Rifle type, and squirrel rifles that might exceed such velocities are rarer than rare things at a rare party, it would seem that his problem lies not with physics, but with a bunch of grey cardigan clackies with attitude.

    tac
    Last edited by tacfoley; 06-11-2014 at 07:17 PM.

  7. #22
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    I was hoping to put an upper bound on the energy of a projectile from a given weight of BP. The amount of energy in BP is not dependent upon its grain size.

    The maths are correct, unfortunately the (in)efficiency of realising that energy makes the number useless.

    The rate of deflagration is admittedly different for different granularities and is also dependent upon the peak pressures achieved - the chemical energy contained therein is a constant by weight.
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  8. #23
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    Quote Originally Posted by Turnup View Post
    I was hoping to put an upper bound on the energy of a projectile from a given weight of BP. The amount of energy in BP is not dependent upon its grain size.

    The maths are correct, unfortunately the (in)efficiency of realising that energy makes the number useless.

    The rate of deflagration is admittedly different for different granularities and is also dependent upon the peak pressures achieved - the chemical energy contained therein is a constant by weight.
    If your posit is correct, why then do we get more velocity out of a given weight of Swiss powder than we do for the same granulation of non-Swiss powder? Can it be simply because the Swiss use willow charcoal and British makers don't?

    There are way too many vagaries in BP shooting - the amount, or lack of, compression of the charge, the bore-wear, bullet windage, temperature, humidity and so on.

    tac

  9. #24
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    Quote Originally Posted by tacfoley View Post
    If your posit is correct, why then do we get more velocity out of a given weight of Swiss powder than we do for the same granulation of non-Swiss powder? Can it be simply because the Swiss use willow charcoal and British makers don't?

    There are way too many vagaries in BP shooting - the amount, or lack of, compression of the charge, the bore-wear, bullet windage, temperature, humidity and so on.

    tac
    Are there any British BP manufacturers any more?

    Yes lots of variables, and different powders and different granulations do perform differently.

    ME variations are not about the amount of energy in the powder, it's about the rate that the energy is released.

    Variations in the source of carbon and method of carbonisation (the folks over at rec.pyrotechnics certainly rate willow charcoal, and IIRC mountain ash charcoal is also considered good) will have only a tiny effect upon the amount of energy in the powder (it's just chemistry). I contend that differences in ME from identical amounts of different powder (or even the same powder at different granulations) are directly related to differences in the rate of deflagration, faster giving a more efficient conversion of chemical energy into kinetic energy. The (surprising to me) inefficiency of conversion from chemical to kinetic energy in a firearm means that only a small improvement in conversion efficiency can have a significant effect on the resultant ME. Another major factor in deflagration speed is how intimately the constituents are mixed. The finer the constituents are milled, the faster the powder. This of course takes time in manufacturing and therefore increases cost. It may also be that the "better" charcoals are structurally more sympathetic to fine grinding.

    I postulate that higher speed of deflagration will improve conversion efficiency in the following ways:

    1) less heat loss during the reaction
    2) less powder burning outside the barrel
    3) less time for gasses to escape via touch hole/nipple/cylinder gap.
    4) acceleration effect of internal pressure

    ....but none of this helps the OP.

    Back to the thread:

    Looking at some posts on the MLAGB website forum, it seems that the MLAGB range at Wedgnock has similar ME and MV limits to your range, up to .75 cal. I say "seems" because this is from a hearsay post rather than definitive information. The Wedgnock range has hosted MLAIC international competitions in the past so they ought to know a bit about it.

    Severnsider, I suggest that you think about contacting them http://www.mlagb.com/wedgnock.htm and/or getting in touch with a branch of the MLAGB close to you.
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  10. #25
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    Just to reiterate my last meaningful post - 'it would seem that his problem lies not with physics, but with a bunch of grey cardigan clackies with attitude.'

    tac

  11. #26
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    Thanks for that info Mr Turnup - all very helpful as usual. I have just been PM'd by a Wedgnock member and may get in touch with them as you suggest.

  12. #27
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    Just to answer the "is BP made in the UK"... the answer is no..

    The last dedicated gunpowder mill closed in 1954 in Roslin, just south of Edinburgh. It was run by ICI who closed it as the buildings were being damaged by subsidence caused by local mining, and the licence was withdrawn.

    The incorporating mills were moved to Ardeer, ICI Nobel's main plant where they ran up until the 80s but were not used for making Black Powder. The mills were only used to manufacture meal powder for making safety fuze. As I understand it no pressing or corning took place at Ardeer and corned powder was imported from Troisdorf, Germany for resale as Curtis's and Harvey's and for pyrotechnic use..

    I would agree with your advice that it is impossible to predict GP performance from the chemical makeup. There is wide variation based on milling time, density, grain size and moisture content...

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