The age-old question regarding the role of the size of an
object in it’s ability to be successful, especially in terms of firearms, has
been asked and answered numerous times. However, we seldom look at the shape of
an object; in this case, the shape of the ammunition’s casing. C. C. Merideth
was the first to question case design when he wrote an article for the July
1946 edition of American Rifleman.
His conclusion was that any change to the shape would give only “negligible”
differences when compared to making other changes, such as bullet weight and
shape. However, his conclusion is not shared throughout the ammo-manufacturing
If you are looking to get the most out of your round, or
rather to put as much powder in it as is safely possible, then you should
fireform your brass to the round’s intended firearm. Fireforming describes what
happens to the brass when it is fired from a particular gun. When the gas from
the burning powder pushes the bullet out of the case, it also pushes the brass
against the gun’s chamber, altering the shape of the case slightly, causing the
brass to form to the shape of the chamber.
Wildcatting has been standard practice for advanced shooters
for nearly as long as firearms, themselves, have been around. Wildcatting is
simply taking an already available round and altering it slightly to create a
round that performs completely different than its parent round. This change could
mean altering the shape of the case’s shoulder or necking the case to accept a
different bullet size. The question, though, is whether or not these minor
changes truly alter the performance of the round to any high degree.
G.O. Ackley wrote of his findings following extensive
research he and a couple of gunsmiths performed with actual range time. Ackley,
using his .257 Ackley Improved and a cartridge named “.25x60mm C.A., set out to
prove once and for all if there is indeed an effect from the case design being
altered. These two rounds were chosen because they are the same in both caliber
and case capacity, with their only differences being the shape of the case. They
were so close, in fact, that the capacity difference was only 1.1 grains of
water weight, with the higher of the two being the .257 Ackley Improved.
After their extensive testing with these two rounds, Ackley
discovered that his Ackley Improved outperformed the .25x60mm by only 3-12 feet
per second in velocity. This finding, essentially a zero in extra velocity, can
be chalked up to the light 1.1 grain increase of capacity. Essentially, the findings
were that changing the case design has nearly zero affect on the performance of
One could argue that changing the neck size and shape could
allow for increased powder storage inside the round. The truth is, however,
that the extra powder is negligible. In fact, it could even be unsafe to change
the case shape enough to truly enhance the round, with such a change causing
catastrophic damage to the brass.
Once a case is fireformed to a rifle, you can then begin
safely increasing the powder charge. Do so in slow increments, never increasing
the powder in one round more than a few percent more than that of the previous
round, and always inspect the case properly to ensure there are no case
failures present or possible. If you desire to truly become advanced in
reloading, you can begin wildcatting rounds yourself as you see the need for
such a round in your shooting life.