Further experimentation to photograph black powder guns firing using a GoPro Nero Black 3 were carried out at the NRA range at Bisley, Surrey, UK. The camera was set to WVGA giving 240 frames per second, meaning each frame lasts a little over 4 milliseconds (0.004167 seconds (rounded up)).
Sequences were taken of three different weapons which gave three different results. At the higher frame rate it was possible to follow the fall of the hammer/cock which was captured over 2 – 3 frames representing approximately 8-12 milliseconds (0.008334 to 0.0125 seconds). Although not clear in these web images, the sequences includes the hammer falling followed by the cap firing or powder in the pan igniting at frame 3 or 4. What happen next varied. With the percussion cap weapons the powder quickly burnt and flame emerged but with the flintlock the was a 0.04167 second delay before flame emerged from the muzzle.
With the Enfield the next frame showed more smoke from the nipple followed by recoil but nothing from the muzzle. At around frame 4 flame emerges from the muzzle which blossoms out to extend 350 cm or so over two frames, extending further but diminishing, during subsequent frames.Further frames show the smoke rolling forward and smoke and debris leaving the barrel. It appears that the bullet initially moves slightly forward of the frame front as it was caught in one shot about 9 cm ahead. The flame and smoke apparently quickly catch-up and envelope the projectile making it invisible. At least that is what currently appears to happen. In order to track the bullet advantage will be taken of the hollow base of the Minié bullet. Filling the base with bullet lubricant (in this case a bees’ wax and lard mix) has often provoked the remark that ‘I saw the bullet going down the range’ as the plug of lubricant burnt effectively being a tracer round. It is proposed to use deep-base Minié bullets filled with a special mix which hopefully will burn during the flight of the bullet and make it visible. We shall see.
The following sequence are consecutive frames, just over 4 milliseconds apart (0.004167 seconds) apart.
Sequence 1 (GL firing)
Sequence 2 (GL firing)
Sequence 3 (GL firing)
The big-game rifle, firing a spherical ball, was different. The hammer fell over ?frames, the cap fired, smoke arose from the cap over 2? frames, the smoke whisked away over a further 5 frames? but nothing happened at the muzzle. During this period, which lasted about 0.02917 seconds, the powder in the breach was burning and building pressure. At frame 10? some smoke emerged from the muzzle followed by flame and subsequent frames followed a similar sequence as with the Enfield rifle.
On releasing the cock of the flintlock 2 frames show the cock falling and sticking the frizzen (steel). The next frame sequence of 10 frames show the flash powder igniting flame emerging.
Sequence 1 (Darly firing)
Sequence 2 (Darly firing)