Reloading High Power Rifle Cartridges

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Sources of reloading Data

Reloading guides put out by the powder manufacturers/distributors will generally list a limited selection of data for loads with jacketed bullets for the most common cartridges.

Accurate powders used to list cast bullet loads for most high power cartridges but they seem to have dispensed with this in their more recent free guides.

Published guidebooks by Lyman and the major bullet manufacturers are a good source of data but they can be rather expensive particularly if you only load for a few guns.

I use loading data that I find on the Internet with extreme caution. There are a lot of cranks whose opinion of themselves is far greater than their knowledge or expertise warrants. Generally the infomation on the Powder manufacturers websites are pretty good but there is always a chance that a webpage generated by a webserver can be misrendered.

Selecting Smokeless Powder For Rifle Cartridges

It is always nice to be able to be able to load for 2 or more cartridges with the same powder.

The following table lists some commonly available smokeless propellants and their application in Highpower rifle cartridges where there is free data for jacketed bullets in the most common weights.

Selected Smokeless Powders for High Power Rifle Cartridges
Bullet Weight
Range (grains)
H-335 IMR 3031 H-4895 IMR 4895 IMR 4320 Win 748 H-BL-C(2)
243 Win
NR NR Good Good Good NR Good
6.5 Swede
NR Good Good Good Good NR NR
270 Win
NR NR Good Good NR NR NR
7mm Mauser
NR Good Good Good Good NR NR
30-30 Win
Good Good Good Good Good Good Good
308 Win
Fair Good Good Good Good Fair Good
Fair Fair Good Good Good Fair Good
303 British
Good Good Good Good NR NR Good

Case Preparation

Case trimming is often necessary for bottle neck cartridges that have been reloaded repeatedly. When a cartridge is fired, the brass is pressed between the expanding gas of the propellant and the steel walls of the chamber. Under high pressure, brass will tend to flow somewhat causing the case to lengthen. The general rule of thumb is to trim rifle cases to 0.010" inch less than max length.

Whenever I acquire new or used brass cases, I always full length resize them and often I will trim any rifle brass as well.

High pressure loads will require more frequent trimming. As brass is used it does wear out. Neck cracks will generally form where the brass is thinnest. The most serious type of cartridge case failure is the case head separation. Often indicative of excessive headspace.

Make sure that the flash hole is clean no debris in the primer pocket which will prevent the primer from being seated properly.

Polishing Cases

The primary reason that I polish cases is to remove any grit which might scratch my loading dies. A little tarnish on the case doesn't really bother me.

Some reloaders will use a conventional case tumbler made for the purpose. As for myself, I have found that a small 3 pound rotary rock tumbler1 I bought years ago serves the purpose well enough.

The drum is filled half full with cases and then enough polishing media is added to cover the cases with an inch of material. For polishing media, I generally use ground corn cobs which is a relatively inexpensive material sold in many pet stores as animal bedding.

I have also used ground walnut hulls which pour out of the cases more easily but it takes longer to achieve the same degree of polish as corncobs

Other Pages on the Site about Reloading Metallic Cartridges

Annealing Cartridge cases

Any cartridge case is apt to have been annealed at the factory. After rifle brass has been loaded a few times it becomes hard, brittle and prone to split along the case neck or shoulder. For some hard to get brass, I have found that it is sometimes beneficial to anneal the case necks to get most life out of the brass.

I stand the cases upright in a shallow metal pan filled with water deep enough to cover cartridge case when it is laying on its side.
I will then play the blue flame of a propane torch on the case neck and shoulder until the case color changes to dull red.
Using a dowel or some other piece of wood, the case will be tipped into water to quench the metal.

1. For years, I used a rock tumbler that I purchased from from Harbor Freight to polish cases. While fairly durable, it's original drive belt was a 3 inch diameter rubber O ring which broke in short order. Fortunately I found that some elastic hair bands sold at the checkout at the local walmart store worked quite well as a good replacement drive belt.