School Science Experiment?

[Huvius]

My son is in 7th grade and he needs to come up with a science experiment.
We were kicking around the idea of comparing velocities acheived with a specified charge of different granulations of black - I have 1-1/2F, 2F, and 3F all the same brand to use.
His teacher has given the green light with the understanding that there won't be much to show at the science fair other than a video.
No, he doesn't attend public school ;)

My question is this:
We have a few BPE rifles to choose from (577/500, .500EX, .450EX, 461 Gibbs No.2, 500/450 Nos. 1 and 2Musket and a .45 Colt revolver and a .36cal Navy)
The rifles I have used 1-1/2F in and the pistols 3F.
I also have some Rook Rifles which we could choose from (.300, .310, .320, one chambered for .357 mag) but have only used smokeless in those.

Which firearm would be the best choice for this experiment?
Is there any danger in going with 3F in a large capacity rifle case? I have seen published loads but have never bothered with using 3F in a big cartridge.

[merlin101]

His teacher has given the green light with the understanding that there won't be much to show at the science fair other than a video.
No, he doesn't attend public school That was my first thought, gotta be PC ya know.

Won't you also run into a problem changing caliber/weight/style?
Could you instead work on what the different weight and boolit style does to airdynamics?

[Huvius]

My intent is to select one firearm and one bullet weight and one volume charge of powder and measure the velocities of each granulation of powder.
The assumption is that a higher velocity will be achieved with the finer powder of the given charge since there will be a higher weight for volume of that powder.
My question regards the selection of the firearm.
May be that the 45Colt may be the best choice but I thought a nice vintage rifle would add some historical (and I hate to admit it, a PC) perspective to the experiment. Also a paper patched boolit would be a revelation to these modern kids!

[herbert buckland]

You wil get a bigger variation with a larger rifle caliber,the 500-450 No 2 would be a much better choice than the 577-450 as you would be able to fill the case safely with FFF,recoil will be there though

[country gent]

I would go with one of the rook rifles breech seated and the same case used through out the experiment. Using the same case would negate any case volumne issues. Breech seating the bullets would allo for this same case to be the measure also. Brush, deprime, prime, charge and ad card wad to hold in place. Seat bullet ( paper patched would seat easier) to depth. Done in this way the only real varience would be the powder granulations.

[Huvius]

Country gent, I have never breech seated anything.
Does a rifle need a different throat than usual to do that?
I could do a similar process using my 310Cadet as I simply hand seat the heeled bullets in that case so it would be easy to do at the range with few tools.
I agree that we would likely see a more impressive variance with a bigger cartridge but also see the point about recoil. My kid is not a big kid... I would like him to be behind the trigger to keep this his project.
Perhaps I should consider the Webley '02 in .357. It would make a fun black powder cartridge gun and would be pleasant to shoot.

[country gent]

I only suggested breech seating to remove the cases variable from the equation a hand seated bullet in the same case would have the same effect/outcome/results. The hand seated heeled bullet in the same case would also work. Also keep in mind compression of the powder charge affects efficency of the powder charge

[303Guy]

Measuring volume would as you say, change the charge weight, introducing two variables. Wouldn't it be more revealing to weigh the powder and show the effects of granule size?

I once witnessed the firing of a muzzle loader charged with cannon powder (I may even have fired it myself). I don't know if the powder was measured or weighed but the powder was way too slow and produced a mild push and mild report.

[waksupi]

Something to throw in, divide velocity by grains of powder to find how much gain is expected for each grain of additional powder, and then how it compares to actual chronograph results. That may already be what he has in mind?