Manual

METALLIC CARTRIDGE RELOADING
Data Generation
Data tested for the current handbook included not only the various tests for pressure and velocity at ambient 70 degrees F, but also tests with powder
positioned at the primer and the bullet to simulate muzzle up, muzzle down conditions. Further, the same kind of tests are run at +140 degrees F and
-40 degrees F. A criterion for all these tests was the data listed for handloading provide results which would meet the stringent criteria which Winchester
applied to factory ammunition. Such stringent testing resulted in not listing some calibers and/or bullet weights with Winchester‘s current line of powders
because Winchester was not satisfied with the results. It is possible the reloader would never have noticed the difference, but Winchester wants to supply only
the very best data possible. In some cases, certain loads were not included for safety reasons.
For the present, this data book represents all the applications of Propellants Winchester has been able to qualify. Under no circumstances would Winchester
presume to suggest data which exceeds the Sporting Arms and Ammunition Manufacturers Institute’s suggested recommended
loading limit.
Powder Burning Rates
Do not use any burning rate chart as a guide to reloading.
Burning rate charts are developed in closed bomb tests. The closed bomb test results merely serve as a very vague guide to the laboratory technician
equipped with the necessary pressure testing equipment. Closed bomb charts as developed by a powder manufacturer include only powder of their
manufacture. So-called "burning rate charts" are usually the result of estimates of where powders would fit if they were to develop a closed bomb test
list for all brand powders.
When powders are used in cartridge cases of varying sizes and shapes, the so-called burning rates can and do vary depending upon the exact set of
loading circumstances. One can easily discover this by care-fully examining a manufacturer's loading data.
Such changes in apparent burning rates come as no surprise to the ballistician who regards closed bomb test results as merely a very crude guide. The
same changes, however, have resulted in more than one reloader having trouble when attempting to extrapolate data from a burning rate chart.
Reloading data should never be extrapolated and since burning rate charts tend to be misleading, and are often the source of grief to the reloader,
Winchester does not suggest the positioning of Winchester® powders on any burning rate chart.
Old Brass
Most of the older, obsolete cartridge cases were designed for use with Black Powder, the only available propellant at the time. The primers used contained
a mercury fulminate mixture as the initiator. The mercury, by itself, is ruinous to the brass case, if it comes in direct contact with it, causing embrittlement and
weakening of the brass structure. Fortunately for the old-timers using black powder, the powder fouling itself tended to dilute the effect of the mercury on the
brass case.
The advent of smokeless powder greatly magnified the mercuric effect upon the brass cases, particularly those cases which were reloaded and refired. The
cleaner burning propellant and the stronger primers used allowed the mercury to be driven deeper into the brass, causing serious weakening of the case.
The use of mercury in commercial priming mixtures continued in the U.S. until the early 1930s, when lead styphnate replaced mercury in priming. An
exception to this was the continued use of a mildly mercuric priming mixture by Winchester for Super-Match® 30-06 Springfield and 300 H&H Magnum
cartridges. This primer was discontinued in 1960.
Since it would be unusual for a present day handloader to acquire old and/or obsolete brass cartridge cases and be able to identify the period of
manufacture, it is not worth the risk of injuring a shooter or damaging his gun to attempt to load such cases. Therefore, Winchester suggests not reloading
old brass cartridge cases.
Loading Instructions
CAUTION: Carefully read the information on the powder can label and follow the recommended loading instructions and precautions contained herein
before using the reloading data.
These suggested loads are based on results obtained in the Winchester laboratory under carefully controlled conditions. They are offered without a fee as
an aid to handloaders, to be employed at their own discretion and risk. Since Winchester has no control over the circumstances of loading, Winchester
assumes no liability for the results obtained.
The handloading of centerfire metallic cartridges should be undertaken only by those who are familiar with all safety precautions and who observe
conservative practices in reloading operations. The powder charges shown are maximum and must not be exceeded.
Cases
Exercise extreme care in inspection of cases. Be sure cases are kept trimmed to the required length. Excess case length is a common cause of difficulty in
reloading. Cases should be discarded prior to the fifth trimming.
Primers
All primers used for testing of the data were standard Winchester primers of the applicable size. Use caution against the substitution of any component as it
can alter the ballistic level of the load. The only magnum primer used in the data testing was for 357 magnum cartridges.
Powder
Check all powder charges with a good scale. All loads listed are maximum loads. You must start 10% below the suggested load and work up to the
maximum load carefully.