Ballistics data needed for Lyman GP Hunter, .54 cal flintlock

[caionneach]

I have an extra barrel for my Lyman Great Plains Rifle in the "Hunter" series having the 1-32 in rifling for conicals. My 13 yr old son and I recently paid a visit to my father-in-law in Arkansas who had the foresight to install a shooting range in his back yard back when he built his house. This was a quick trip, and I ended up not getting everything I needed for the range, like my powder measure!

I need ballistics data for the following shooting at the range since I had forgotten to bring my possible bag which had my powder measure (!) and so I had to guesstimate by using the cover the projectile with powder in the palm of your hand method. At least that is a somewhat consistent method. The problem, however, is that I was using a Thompson-Center Maxi-Ball as the projectile!

When I returned home I got out my trusty Lyman D-5 powder scale and weighed what I had been doing at the range, and the charge turned out to be 155.25 grains of 2F black powder!

So that was a 430 grain Maxi Ball propelled by 155.25 grains FF.....

I shot 12 shots at the target and got it dialed in, but that was the toughest bout of shooting I think I have ever done in my life! My shoulder is still a bit sore from it, lol! But she fired true and each shot responded to the sight adjustment I made. I should also mention that I was using the Lyman peep sight for the GPR on this hunter barrel. Very cool sight! One thing about shooting the Maxi-Ball in the hunter barrel, each shot loaded very easily since the previous shot had burned so thoroughly and left little residue, even using FF and an inordinate amount of powder. Beat on my shoulder though!

I have it sighted at 3/4 in high at 25 yards. I couldn't remember if I was supposed to be 4 inches high at that range for a 100 yard zero or not, so if anyone has the Lyman Blackpowder Manual and a ballistics table, maybe you can share the information.

Maybe a 75 yard zero would be better with this bullet's trajectory. I think a follow-up session at the range is in order **with powder measure** and using a more acceptable hunting load, perhaps 70 to 90 grains FF! But I'm curious to know what the ballistic data is, muzzle energy, muzzle velocity, that sort of thing. Thanks.

 

[caionneach]

Looks like I was able to answer my question with a quick search for Thompson-Center Maxi-Ball ballistics, and it appears I was slightly over maximum according to T/C's stats.


Muzzle velocity for 150 gr 2F is 1576 fps, 2400 ft. lbs muzzle energy. I was 5.25 gr over that amount.

That load made lots of smoke, and it appeared to burn all of it in the barrel as I don't recall any burning powder exiting the barrel.