April 2026 (2) - Flipbook - Page 38
from a 13° boat tail to a 9° one.
Something I have spoke of here
before, subsequently ignored by
most. Something I had personal experience with, back in my
service ri昀氀e days in the mid 80s
to 1994.
Interestingly enough, the pitching and yaw of a bullet, particularly the yaw, has a de昀椀nite e昀昀ect
on the precession of our bullets.
There is a speci昀椀c name for the
precession angle a particular
bullet settles on, it’s called Limit
cycle Yaw.
The 昀氀at base of our BPCRs de昀椀nitely helps mitigate our bullet’s
precession a great deal, until the
Phase Inception Point or Magus
Moment. Here, we understand
that at that instance of time,
the bullet’s 昀氀ight is much more
susceptible to an unseen condition change. Whether this takes
place around 900 yards with a
Bpcr bullet, or at 1.4 miles with
a modern bullet. The e昀昀ects are
the same on any spin stabilized
projectile, the same physics
apply.
The pitching and Yawing is also
e昀昀ected by the initial tipo昀昀 at
the muzzle. This pitching and
yawing exhibits both a fast (nutation) and a slow (precession)
frequency. The combination of
these two frequencies is called
Epicyclic motion. The fast arm
or nutation usually dampens
out rather quickly, the slow arm
May or may not dampen out….
This is basically due to the bullet’s ability to handle the down
range conditions. Based on the
mass, aerodynamic properties of
the bullet, and the Spin rate. All
this is in Litz’s 2 volume book on
Modern Advancements in long
range shooting. Much of this is
38
pertinent to our shooting, but
what we lack is the deep testing
of radars capable of down range
readings, such capabilities that
are far beyond our small labradar
units.
This information however ties in
rather nicely with Brother Rick
Moritz’s 昀椀ne article in the most
recent Black Powder Cartridge
News Winter edition. Where he
mentions Angular Momentum.
If you missed that part I would
suggest you reread the article.
Our old friend Dan Theodore
tried very hard to apply much of
Dr Robert McCoy’s theory to our
bullets. With considerable success, however, there are some exceptions. Dan followed the smaller caliber, longer bullets, faster
twist logic, lesser recoil theory to
the tenth degree. However Dan
somewhat ignored the science of
Angular Momentum obviously.
Dr McCoy though provided all
the necessary math to today’s
modern ballistics. However never
did he dive into actual ballistics
testing of 昀椀ring down range, ie
Actual 昀椀ring. We can de昀椀nitely
thank him for the math, though
which is far beyond my own level
of thinking and thought process.
Litz on the other hand, has done
nothing but, with considerable
down range radar testing. We
shooters owe him some measure of thanks, giving us a better
understanding of even our ballistics.
Dan Theodore was attempting
to get away from the excessive
recoil of the bigger 45’s and 50’s.
We experimented with the 25#
Sharps Con昀椀guration, in 45-110
or 45-100. Unfortunately these
have their own limits, while
dampening recoil considerably,
they can be tiresome managing
on the bench or prone due to
excessive muzzle weight. They
however do the job rather admirably, 2018 midrange prone
at 600; yards a 25# 45-110 with
a Paper Patched bullet 昀椀red the
high score on day 1. Was 3rd at
300 and 500 yards overall. Securing a Scope Midrange Prone
National Championship in the
e昀昀ort. So that old wives tales
of 45-110’s don’t shoot, well BS
to that. There are Plenty more
examples to further dispute that
claim. Even a record or two,
along the way.
This kind of setup is better suited
to the bench these days in my
opinion. Still it is Heavy and
tiring to manage all day for close
to 50 shots.
Tipping: The phenomenon of a
bullet “tipping” or experiencing
an angular change as it exits the
muzzle is primarily referred to as
muzzle yaw, which contributes to
a larger e昀昀ect called aerodynamic
jump.
This initial instability upon exiting the barrel is a major source of
bullet dispersion and is caused by
several factors:
• Muzzle Blast and Asymmetrical Gas Flow: As the bullet
leaves the barrel, high-pressure
gases following it can overtake
the bullet and impact its base.
If this gas 昀氀ow is asymmetrical,
perhaps due to an imperfect or
non-square muzzle crown, it can
give the bullet an uneven “kick,”
causing it to tip or veer o昀昀 its
intended line of departure. This
is where our multiple wads help
prevent gas cutting and lessen
the possibility of tipping o昀昀 when
exiting the muzzle. Also bullet
concentricity with the bore is of
April, 2026 - Issue #2
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