New muzzle
loading customers, quite understandably, ask this question again
and again. We wish that we could give an accurate answer, but
the fact of the matter is that there is just no shortcut to
learning the trajectory of your muzzle loading rifle with the
projectile you have chosen, your powder charge, and ambient
conditions you hunt in.
Trajectory is
figured 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 does it mean 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 muzzle
loading bullet manufacturers use static ballistic coefficients.
No mention is made of how these numbers are derived, at what
range, velocity, ambient conditions, and so forth.
Most of
today's hunters use the popular saboted projectiles in .45/.50
caliber with weighs 250 to 350 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
are practical limits in this caliber and weight range. Anything
over a .210 BC should be considered good.
For our
purpose of round balls, a personal chronograph is needed, there
are economical units available and widely distributed. The
budget minded shooter can usually go in with his shooting
buddies to off set costs. At least it gives you a good starting
point.
Once a
suitably accurate load is found with a small velocity deviation,
you can fly 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. With that knowledge on your personal
load you have more information than any powder manufacturer, gun
maker, or bullet maker could provide to you. Using muzzle
velocity and 100 yard velocity, you can use free software, such
as the "Point Blank" program from HuntingNut.com,
to give you a 150/200 yard numbers that has some basis in
reality, and some relation to actual field results.
There is no
real substitute for doing your own shooting, 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? The
debates about bullets come and go, but nothing can possibly
compensate for poor shot placement. A load that groups at 100
yards may not be acceptable at 150/200 yards but an accurate
load at 150/200 yards seldom has any trouble at 100 yards!
Hope this
helps some of you that have asked us this question.