Black Powder firearms and muzzle velocity measurement?

[severnsider]

If you allow .357 carbines, then BP will not exceed their velocity.
Energy is unhelpful on ranges, as a .50 cal BP at full stoke will have a very high energy, but losses it very rapidly compared to a .308 for example.

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.

[tacfoley]

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.

[severnsider]

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

[tacfoley]

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.

[Turnup]

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.

[tacfoley]

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

[Turnup]

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.