How High at Fifty Yards to be "On" at 200 yards?
New muzzleloading enthusiasts, quite understandably, ask this question again and again. I really wish that I could give an accurate answer, but the fact of the matter is that there is just no shortcut to learning the trajectory of your muzzleloading rifle with your projectile, your powder charge, and under your ambient conditions.
Trajectory is contingent on two basic factors: muzzle velocity and the ballistic coefficient (BC) of your bullet. Guns vary quite a bit, and just because one shooter records a number on a chronograph with his identical model rifle in no way means that your gun will shoot at the same velocity. You really need to do your own chronograph work. A rumored velocity may be off by 200 fps in your gun, or even more.
Most muzzleloading bullet manufacturers use static ballistic coefficients, and with rare exception (Winchester-Olin) give horribly inflated numbers. No mention is made of how these numbers are derived, at what range, velocity, ambient conditions, and so forth.
Most of today's popular saboted projectiles are .45 caliber and weigh 250 to 300 grains. Only so much can be done to such a projectile to make it fly better. A few hundredths of a ballistic coefficient point can be gained by changing the nose profile, and adding a boat tail can make small gains, but there is a practical limit in this caliber and weight range. Anything over a .210 BC should be considered excellent. If you see a published BC over .250 or so for this class of bullet you are reading a spectacular lie.
So, what to do? Sometimes, you just have to pull the trigger. Personal chronographs are more economical and widely distributed than ever before, and the budget-minded shooter can usually go two or three ways with shooting buddies if need be. That at least gives you a starting point.
Once you have a suitably accurate load with a small velocity deviation, you can sail your bullet over that chronograph at 100 yards. Those readings leave no doubt as to the velocity (and energy) of your bullet at 100 yards. Now you have far more knowledge about your personal load than any powder manufacturer, gun maker, or bullet maker could possibly provide to you. Using muzzle velocity and 100 yard velocity, you can now use free software, such as the excellent "Point Blank" program from HuntingNut.com, to give you a 200 yard number that has some basis in reality, and some semblance to actual field results.
Still, there never is any real substitute for doing your own shooting. After all, if you can't hit what you are shooting at under range conditions, what hope do you really have for successful shot placement in the field? Debates about bullets come and go, but nothing can possibly compensate for poor shot placement. Further, a load that groups well at 100 yards may not be acceptable at 200 yards--but an accurate 200 yard load seldom has any troubles at 100 yards!
Copyright 2004 by Randy Wakeman. All rights reserved.