The rifle data contains data for
most of the popular cartridges. The components specified were those
that were commercially available to the handloader at the time the
tests were performed.
The powder charge weights specified
represent loads that developed Maximum Allowable Chamber Pressures
with the test barrels used and components specified, with the exception
of loads that are specified as (C) compressed charges which may
represent case capacity rather than maximum chamber pressure. All
tests were conducted utilizing commercial barrels in a Universal
It is not unusual for reloads assembled
with particular components and fired in the individual reloader's
gun to give ballistic results (particularly chamber pressures) that
vary in either direction from the published data. To compensate
for any component and/or gun combination that would tend to yield
pressures in excess of the published data, it is recommended that
the powder charge be reduced 10% initially. (This reduction in powder
charge weight should also be made each time that any of the components
in the load are changed.) After firing several loads at the lower
powder charge weight - without ANY evidence of excessive chamber
pressure - the powder charge weight may then be increased in 0.5
grain increments as accuracy needs and pressure indications permit.
The subject of excessive pressure along with illustrations is included
in most reloading manuals, and should be read before attempting
Always make certain that you use
the correct ammunition in your rifle.
This data must be used only with
IMR Smokeless Powders. Never use this
data for powders that may have similar numerical designations!