Sight adjustment switching from maxi to round ball

[kencolamarino]

Went to the range last week with a recently acquired T/C Hawken 50 caliber flinter that I had been shooting with a 370 grain maxi and 80 grains of 3F. It was sighted in to print 2.5 inches high at 50 yards, which is just about dead on at 100. I wanted to sight it in with a tight patched round ball (.018 blue pillow ticking patch and 80 grains of 3F). Obviously, the round ball load will be traveling faster, around 1800 fps versus around 1300 for the maxi.
Now the problem. Everything I know about interior and exterior ballistics says that a lighter, faster bullet will shoot lower than a heavier slower bullet in the same gun. However, when I shot the round ball at 50 yards, it printed considerably higher, requiring the rear sight to be screwed down all the way down. Even then, it shot about 3 inches high at 50 yards. This was sighting to put the front ball directly in the middle of the bull with a tight bead. With this sighting, it should be dead on at about 110 yards. I could always sight to the top of the front ball to be dead on at less than 110 since the rear sight won't go any lower, but wasn't taught to use these sights that way.
1. Anyone else have problems getting rear sight low enough to shoot a patched ball?
2. Why does a patched ball shoot higher than a heavier maxi against all logic?

I am, to say the least, nonplussed.

 

[boar]

My first ML (82) a .54 TC, I shot RB with 42 grs 2ff, Maxis with 110grs, same sight adjustment. Have killed a groundhog 70yrds with 42grs, pumped right tru him. It would hit bottom of clorox jug at 115 yrds all day with the maxis and 110 grs. Would split the ball on a axeblade. Grandson has it now. I shot my first deer with it in 83. Killed hundreds of groundhogs with it. Dilly

 

[WV MZL HUNTER]

By using 3 f powder I would use 60 gr.
If using 2 f Powder I would use 80 gr.
Very close to the same load and more than enough to hunt Whitetails on down to small game. :thumbsup: In a 50 cal.

 

[rice1817]

In my experience, the light-bullet-shoots-lower phenomenon applies mostly to pistols with the very short barrel time and the light weight of the piece making muzzle rise more of a problem. With a HP rifle, I have always found my lighter bullets to shoot higher with the same powder charge...function of higher velocity for the same powder charge with the lighter bullets. With round balls, although you have probably 30% greater muzzle velocity, the poor ballistic shape sheds velocity much faster than the conical. If you are starting your roundball at 1800 fps and your conical at 1200 fps, the 50 yard impact will be higher, but I would bet that at 100 yards the POI would be similar.

I don't like the bead topped front sights on MLs for this reason. With a partridge front sight, one could always install a higher front site, file it to get dead on with a given projectile at a given range with the rear sight at mid adjustment, then you would be able to shoot other projectiles and loads by dialing in the rear sight.

 

[Dalekg6]

Not different loads but on my 58 cal Kodiak double rifle it was hitting too high even with the rear sight all the way down. I had to take off the rear sight and grind off some metal from the bottom. That lowered everything and now it sits right in the middle of the adjustment range.

 

[GreyWhiskers]

Only input I can give is that my TC .50 Hawken is sighted in at about 1" high at 25 yards with RB. When I use those 370gr MaxiBalls they hit 3" low at same distance. That's a 4" difference at 25 yards. Not sure why your sights aren't low enuf to sight in with RBs though. GW

 

[tg]

I think that fle to suit sihts are the way to go with a ML, and most all the reports I have heard of ball vs conical have the ball hitting higher.

 

[ApprenticeBuilder]

Also something to think about, without a chronograph to test your particular loads you may not be reaching the velocities you think, published data is a very vague guide at best. I learned this with centerfire handloads, the differences can be drastic.

I did a little work this weekend with a chrono and was surprised at the results achieved, as well as the variations presented.

I will be getting into this a bit deeper as the summer progresses and post the results of my tests.

 

[Hunter66]

"Everything I know about interior and exterior ballistics says that a lighter, faster bullet will shoot lower than a heavier slower bullet in the same gun."

You are confusing the facts. A faster lighter bullet will shoot flatter than a slower heavier one. A slow bullet would have to hit the target higher at mid range to be on at say 100 yds. versus a faster one. A maxi may be 2 1/2" high at 50 to be on at 100 while a PRB may be 1" at 50 to be on at 100. What you are seeing is a product of the sight picture. The prb is hitting lower in the parabolic arc of flight but your sights direct it higher on the target until you crank them down. If you bolted the barrel down perfectly parallel to the ground and fired those bullets at a target without using any sights the lighter faster one would hit higher on the target than the slower one because it covers more distance in the same time period of the bullets fall to the ground.