Black Powder firearms and muzzle velocity measurement?

[Turnup]

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.

The only definitive means to assure compliance is by use of a chronograph or ballistic pendulum.

That said, I believe there is no way that a BP rifle will exceed the range MV limit of 2145 ft/sec.

You must also comply with the calibre limit, so taking a .44 ball as 148 grains, to be within the max ME then MV must not exceed 2134 ft/sec, which seems decidedly unlikely with a BP rifle.

Assuming a very generous 1500 ft/sec MV, then to make 1495 ft-lbs you would need a 300 grain projectile, which I suppose is possible with a long bullet (is there a .44 Whitworth?), but at that weight you would not achieve 1500 ft/sec.

It does not seem likely that a BP rifle in .44 cal or smaller would exceed your range limits.

I am also surprised by the statement "...certified for .22RF rifles and pistol calibre rifles ..." Far from clear how you would recognise a pistol calibre BP rifle.

Are you quoting from the pukka range safety certificate, or local range rules ?

The few range safety certs I have seen address only pistol and/or rifle, MV, ME, and sometimes calibre limits. Not seen .22rf and pistol calibre rifles mentioned on a safety cert before.