Reloading any cartridge requires a familiarity with safe, conservative reloading practices. When combined with personal discipline and attention to detail, such practices can help create a margin of safety for both the reloader and the shooter.
Lot-to-lot variations, design changes, or specification changes that are beyond our control may affect components mentioned in this book. To safely use this or any other guide or manual, you must keep yourself well informed on the technical progress of reloading. It is our belief that the information offered will result in safe operation if the proper equipment and components are employed in a reasonable manner.
Because Norma Precision AB has no control over the actual components selected, the manner in which the components are‑assembled, or the condition or quality of firearms used, no responsibility, either expressed or implied is assumed for the use of this guide or for any other Norma product. In no event shall Norma Precision AB be liable for any damages resulting from the use of this book, whether in contract, tort or otherwise, including consequential damages.
To maintain the product quality for as long as possible, you have to keep the powder in a suitable place under suitable conditions. Where possible, store the powder at a constant temperature, ideally between 12 and 15°C, and a relative humidity of 40–50%. If the air is too dry, it will dry out the powder, which will cause the pressure to be higher, thus affecting performance. Also make sure that you close the powder container properly afterwards.
Cartridges should be stored under the same ambient conditions to maintain their quality.
When comparing different burning rate charts, one will notice variations in listed propellant ordering. Still, each such chart tells "the truth". Ranking differences result from use of different criteria. For example, a certain powder type can act slightly quicker than some other powder type, when used in 308 Winchester loads; however, when these powders are used in 7x64 loads, evident burning rates might reverse. Relative burning rate charts can never provide absolute data because too many factors are involved in how propellants burn within a cartridge chamber.
Eurenco Bofors produced the following chart, which we have published in our Norma Reloading Manual. Their ballisticians tested the same powder charge (43.2 grains) using the same bullet (143-grain FMJ) loaded in the 308 Winchester - they used IMR 4350 performance as a reference. This chart may not be any more accurate than any other but, compared to most, it does give significantly more information about how the relative burning rates were derived and it does relate to at least one real-world situation.
Any such data chart should be used ONLY as an INFORMATION GUIDE. Always refer to published data when reloading.
|Vihtavuori, N 350||197,6||949,8|
|Vihtavuori, N 105||187,1||675,3|
|Rottweil P 806||179,5||630,4|
|Accurate, XMP 5744||145,8||607,2|
|Hodgdon, H 4227||161,5||414,2|
|Vihtavuori, N 125||145,5||293,7|
|Alliant, Re 7||143,0||257,1|
|Rottweil, R 901||138,7||232,0|
|Accurate, XMR 2015||129,0||203,6|
|Hodgdon, H 322||131,9||202,9|
|Vihtavuori, N 130||131,8||195,2|
|Vihtavuori, N 133||130,6||185,1|
|Vihtavuori, N 530||130,0||174,5|
|Hodgdon, H 4895||127,5||173,6|
|Rottweil, R 902||126,6||170,0|
|Vihtavuori, N 135||126,5||160,6|
|Vihtavuori, N 140||125,5||157,3|
|Hodgdon, H 335||125,2||151,7|
|Alliant, Re 12||122,1||144,5|
|Rottweil, R 907||115,0||137,9|
|Vihtavuori, N 540||119,3||137,5|
|Alliant, Re 15||120,0||133,7|
|Rottweil, R 903||114,5||122,0|
|Vihtavuori, N 150||115,7||118,0|
|Vihtavuori, N 550||111,2||112,6|
|Hodgdon, H 380||112,0||112,0|
|Hodgdon, H 414||111,3||110,9|
|Vihtavuori, N 160||102,1||107,5|
|Rottweil, R 904||101,0||99,1|
|Allitan, Re 19||94,8||90,7|
|Rottweil, R 905||92,9||89,9|
|Accurate, XMR 4350||94,2||84,4|
|Vihtavuori, N 560||91,1||83,2|
|Alliant, Re 22||90,2||81,1|
|Hodgdon, H 4831||91,1||77,3|
|Alliant, Re 25||83,1||71,8|
|Vihtavuori, N 165||83,7||69,3|
|Vihtavuori, N 170||74,8||38,7|