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Thread: 50 cal trajectory

  1. #1
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    Default 50 cal trajectory

    My son and I just got back from a range session with his .50 cal treehawk with iron sights

    With 370 grain concicals and 80 grains of ffg it seemed pretty consistent +3" at both 25 and 50 yards (as far out as we could safely go on this range)

    anybody have an idea from experienc what kind of drop we could expect at 75 and 100 yards?

    is this rising UP through +3" at 25 and back DOWN through +3" AT 50 yards?

    we're both new to muzzle loaders so I'm trying to apply what I know of smokeless/modern rifle ballistics

    I know the ultimate solution is more range time but for right now that's not possible so any information in the meantime would be most helpful...

    Thanks!!!

  2. #2

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    You are shooting a load pretty similar to the one I've used the past few years. Mine set-up is a 390 grain Great Plains Bullet over 85 grains of Triple Seven FFG. I"ve found mine is about the same at 50 and 100 yards. I'll admit first, I have a tough time shooting with open sights at 100 yards and definitely need a solid rest to rule out "some" shooter error. Anyway, I've found if mine is on the mark at 50 I can usually put it on the mark at 100 (give or take an inch or two on some shots to account for my poor eye sight). So I assume mine is rising at 50 and dropping at 100. I've never tried shooting beyond 100, or at 25 or 75 to see where it hits.

    Not sure if this helps or not. But if you're 3" high at 50 I might not be surprised if you're still high at 100.

  3. #3

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    I'd sure go out and shoot it again. Details in trajectory are going to vary due to sight height, barrel length and the shape of that specific bullet- especially as range stretches.

    I haven't tried 50 cal conicals, but my load combo in my 54 is an inch high at 50, right on at 75, and about 4 low at 100. Guessing from your charge and my other experiences in 50 cal, I'm betting that if you're 3 high at 50, you're going to be even higher at 75 and still high at 100, but that's a guess. The thing that is really throwing me is your 3 high at 25. In my experience that would probably make you 6 high at 50, 8 or 10 high at 75, and probably 3-6 high at 100.

    Way too much speculation for my blood, so I'd sure shoot it again to verify your hits at all ranges. I particularly like the sighing I'm using, because for most shots out to 100 I can hold right on without fear of hitting too high or low in between. My eyes make sighting and sure hits on game problematic further than that, so I've never even tested it further.

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    somewhere is all the reading i have just done on blackpowder (maybe fadala's book?) i recall seeing that trajectory at 17 yds is analogous to 100 yds... granted there are a ton of variables....
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    I am shooting .50 295gr powerbelts, 100gr. FF, 1696fps, iron sights. From my records I am 1.5 high at 50, 0 at 100, and -6 at 150.

    From memory, I think at 25 I was for practical purposes right on, maybe just a hair high. With my zero at 100, 50 is pretty much the high point in the arc so at 75 I would be close to an inch high.

    Your 3 high at 25 seems really high. That would be a heck of an upward arc. On mine it does seem that what I would get at 17 would be equal to 100, interesting concept!

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    This is the info I was able to find.
    On Page 181 of the "Lyman Black powder loading manual" the muzzle velocity of a 370 grain conical (ball. coef. .095, se. dens. .208) leaving a 24 inch barrel with 80 grains pyrodex RS is 1282 fps,and at 100 yards is travleling 963 fps.
    On page 238 of Fadala's "Black powder handbook 4th edition,revised and expanded" he describes the following: "Rifle calibers 45 through 58, whether shooting a round ball or a conical, can be pre-sighted in at 13 yareds for starters. This normally puts the bullet back into the line of sight at about 75 to 80 yards, considering a round ball at about 2000 fps and a conical at about 1,500 fps. Sighted to hit an inch high at 50 yards, the round ball or conical will hit an inch or so low at 100 yards and about a half foot low at 125 yards."
    Based on Fadala's information as it applies to your senario my best guess is you should be 1 to 2 inches high at 100 yards.( if we dont take into consideration humidity, temperature, wind,ect.)

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    Thumbs up Not quite Addin' UP

    Loads of variables could be coming into play... nonetheless, two aspects to keep in mind (with all black powder & equiv. in .45, .50, .54, .56, .58 & so on) will be a relatively heavy chunk of lead flyin' at low end velocities.

    An interesting comparison by your understandings "I know of smokeless/modern rifle ballistics" could be akin to progressive powder burnin' Big-bore handgunning down range performance.

    #1. I'd give yourself just shy of 20 yards on target distance for the initial sight in. First make a foul shot --- Then on a steady benchrest... using irons try a 6" filled-in, circle-type target... aim @ the 6 o'clock edge -bottom- of the circle... place some 3 shots in a tight group right on that 6 o'clock hold.

    #2. Possibly do a quick clean & take that fouling shot again.

    #3. Next is perchance up to your range options --- if you have 50 yards, go ahead and hone in the right to left sight-in using the same target scheme as above. This is just for right to left NOT really a final up & down.

    If you have 100 yards to work with --- go all the way out and verify based on the same practices of #1. Keep in mind you should always be aiming @ 6 o'clock!!!! & hitting @ 6 o'clock!!!! You are not going for Bullseyes!!!

    I think you will find what a few are saying here --- that just shy of 20 some yarders will give you about 100 up & down... however, very likely may not give you a honed in right to left or perfect up & down mark on the paper.

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    Default Temp has a lot to do with trej.

    The temperature has a lot to do with the trejectory you will get out in the field. The muzzleloader hunt in 20-A is held in November. Temperature can be anywhere from +20 degrees to -35. At say minus 10 you gun will not shoot anywhere near where it shoots at +40 degrees. The colder it gets the lower the performance. My 12 year old son and I got real intamate with his .58 when he got drawn for 20-A muzzleloader moose. He could hit a 4" pie plate all day long at 100 yards. Temperature during our practice times was +50 and +40 degrees. When November came around he got his first shot at 80 yards and the bullet hit between the mooses feet. He could not believe he had missed at that range. So the next time we got closer, 40 yards, he still hit 5" lower than he had aimed. Temperature was -25 the day he took his shots.

    So you need to practice at the temps you will be hunting at.

  9. #9

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    I would recheck the sight picture and sight in at 12.5 yards or 37.5 feet. It is so much faster to get sighted in at this range and then verify the shot group at 75 and then 100 yards. You will probably be less then a couple inches high at your mid-range. Good luck

  10. #10
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    When we talk about trajectory of any projectile we need to consider a couple of things. When you reference rising and falling at different ranges it is reference to the line of sight. The bullet rises to cross the line of sight at some close range then reaches its highest point (M.O.)then falls below the line of sight at what will be the "sight in" range. The line of sight is considered to be level and straight and the line of bore is angled slightly upward. The bullet of course begans to fall as soon as it exits the barrel.

    This line of sight is at a certain heigth above the bore. With one type of sight it will be maybe 3/4" with another maybe 1" and with a scope or dot system it will be about 1 1/2". So, the down range point of impact at a given distance, referenced to this line of sight will vary with the type of sights installed in the rifle. At 1800 fps a bullet (BC .250)would have about a 5" M.O. (highest point) with a 100 yard zero. As you establish the line of sight up and down you can see how the POI will be referenced to this line of sight differently.

    Actually temperature has very little effect on trajectory (air density) but will have a greater effect on velocity due to powder characteristics and that can have an effect on trajectory, when the temperatures vary as much as 60 degrees F.

    Muzzle loaders are very much like big bore handguns as Brian has said and it is with long range big bore revolvers that I got my education with this trajectory. (well, that and a degree in Ballistic Science) I think with most of us we can't shoot close enough group with irons at 100 to make good trajectory measurements or sight adjustments. I have been able to shoot a few 4" groups at 100 with ironsighted revolvers at 100 yards but for some reason that ability is waning.
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