Black Powder firearms and muzzle velocity measurement?

[severnsider]

Good evening Gentlemen. I am in the process of putting together some facts relating to the use of BP rifles (and perhaps pistols) at our outdoor 50m range. Advice from the NGB is that provided the range MV and ME maxima are not exceeded then there should be no reason to prevent the use of BP firearms (and yes, I'm aware that pistols are treated differently to rifles due to the significantly-increased cone of fire criteria).

My question thus relates to the measurement of MV from a BP firearm. Can they be shot over a chrono without showering it in soot, or are the readings which may be obtained insufficiently accurate/repeatable? Do you have books/loading tables which give a reliable indication of MV for certain types and quantities of powder and weight of shot?

Any help or guidance would be appreciated.

Thanks.

[loiner1965]

you can shoot over a chrono but it must be a distance away from the muzzle or you shoot throught a paper screen which is in front of the chrono...... i prefer the first option.
quickload as mv for bp loads

[severnsider]

you can shoot over a chrono but it must be a distance away from the muzzle or you shoot throught a paper screen which is in front of the chrono...... i prefer the first option.
quickload as mv for bp loads

Thanks for that Stephen. It would seem that both these options could be used by a prospective shooter to demonstrate to the RO that he's within limits then.

[kmahow2]

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.

[tacfoley]

I certainly have tables of muzzle energy, using simple formulae based on velocity and weight of bullet, but there are so many variables in shooting BP firearms that it makes the use of charge weights as a method of calculating velocities unuseable.

Barrel length is also a factor here, as is the type of firearm used.

A Brown Bess using a maximum of 120gr of FFg will certainly 'ring gongs' at the shorter ranges, but as has been pointed out, downrange it's a different story, although at 50m it is not going to make much difference. Our 50m range, for instance, permits the use of LEAD projectiles up to and including .75cal to be shot, providing that they do not exceed 1500 fps. No Brown Bess on earth is going to match a 12g Brenneke slug either for velocity or m/e, and that is permitted on our range.

To get 1500 fps out of a Black Bess you are going to use an improbably high load - always supposing that such a load would actually be burnt in the barrel.

No BP handgun on earth is going to make 1500 fps - the usual limit of velocity, but letting us know the calibre will let us figure out the m/e, too.

A lot more information is needed from the OP before I could try and offer any meaningful advice.

So, OP, come back to me with the following details, and I just might be able to help you.

1. Type of firearm[s] proposed.

2. Current restrictions on YOUR range.

To get you started, here is an easy-to-use m/e calculator - just fill out the blanks -

http://www.americanairrifle.com/convert.htm

tac

[severnsider]

I certainly have tables of muzzle energy, using simple formulae based on velocity and weight of bullet, but there are so many variables in shooting BP firearms that it makes the use of charge weights as a method of calculating velocities unuseable.

Barrel length is also a factor here, as is the type of firearm used.

A Brown Bess using a maximum of 120gr of FFg will certainly 'ring gongs' at the shorter ranges, but as has been pointed out, downrange it's a different story, although at 50m it is not going to make much difference. Our 50m range, for instance, permits the use of LEAD projectiles up to and including .75cal to be shot, providing that they do not exceed 1500 fps. No Brown Bess on earth is going to match a 12g Brenneke slug either for velocity or m/e, and that is permitted on our range.

To get 1500 fps out of a Black Bess you are going to use an improbably high load - always supposing that such a load would actually be burnt in the barrel.

No BP handgun on earth is going to make 1500 fps - the usual limit of velocity, but letting us know the calibre will let us figure out the m/e, too.

A lot more information is needed from the OP before I could try and offer any meaningful advice.

So, OP, come back to me with the following details, and I just might be able to help you.

1. Type of firearm[s] proposed.

2. Current restrictions on YOUR range.

To get you started, here is an easy-to-use m/e calculator - just fill out the blanks -

http://www.americanairrifle.com/convert.htm

tac

Thanks, Tac - that's helpful. The restrictions at the range are as follows:


The range is certified for .22RF rifles and pistol calibre rifles up to .44 cal. only. The use of pistols and black powder firearms is prohibited.

The maximum MV allowed on this range is 2145 fps & the maximum ME is 1495 ft.lbs

We occasionally receive queries from shooters as to why pistols and BP are prohibited. That's a simple matter for pistols (the backstop/bullet catcher/sand bank is not of a suitable size) but I am less sure of the reason behind the prohibition on use of BP. The view of the NSRA was that provided the MV/ME maxima were not exceeded, then there was no safety reason why BP should not be used. This is what led to my original question about (a) how easy it was to measure MV from a BP firearm with a chrono (I assumed, perhaps wrongly, that BP might not give a clear reading), and (b) were there any recognised tables which related to BP.

Although familiar with reloading tables I know nothing of BP. For all I know there may be a whole range of recipes for BP which give fast/slow burn etc, hence my asking the question on this forum where I know a great deal of expertise resides.

No idea what specific model/make of firearm might be used. Perhaps my question should be simply "how straightforward is it for a BP shooter to assure the RO with confidence that the firearm he proposes to use will not exceed the range MV/ME limits"?

From what you have said above, Tac, it looks as though the prohibition on the use of BP firearms might be unwarranted. It might, of course, just be the will of the committee not to have them there which is fair enough I suppose, but whatever the reason it should (IMHO) be made clear to shooters.

[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.