A Look at Alliant Reloder 7
Alliant Reloder 7 was one of the earliest Savage 10ML series recommended powders, and has never been "unrecommended." Fairly slow burning among the Savage compatible propellants, it is best suited for 300 grain class bullets. It is also a fairly low pressure powder for a given velocity. Here's a representative group from today's range work:
Recoil, according to my shoulder, is fairly stout with this load, as you might imagine. Alliant Reloder 7 is a "short cut extruded powder," tan in color, and has a 7% nitro content. As ATK and others have long held, double-based powders have a plasticizing effect. The addition of nitro to the nitrocelluose tends to lock in the moisture content as manufactured, allowing double-based powders to be less susceptible to humidity changes. Also, as in the case of Alliant 2400 (15% nitro) and Accurate Arms 5744 (20% nitro), it is relatively easy to ignite in a low shot start pressure situation-- exactly what the 10ML-II is, as a sabot has a very low coefficient of friction. Where single based powders need backpressure to sustain good combustion, a double-based powder needs less of it-- as the nitro helps it along. Additionally, in severely cold weather, double-based powders can be less prone to velocity loss. All propellants tend to burn slower in cold weather, but as the nitro crystallizes it can get more energetic or "hotter." Where single based powders rely primarily on geometry to control combustion, double-based powders allow the manufacturer to also control energy content based on the amount of nitro added.
Here's a look at the interior ballistics model of our Reloder 7 / Barnes 300 gr. load:
Adjusted for the approximate weight of the orange sabot, we have a 313 grain projectile that changes our model only slightly:
No ballistic model has credence until we confirm velocity with actual live fire. That's what we have done here, note that our prediction is 2359 fps: amazingly close to our chronographed average of 2320 fps. When predicted velocities match actual velocities within 2%, I believe it shows our model is a very good general representation of what is going on.
Due to its ready availability, good lot-to-lot consistency from ATK and Nexplo, igniteability, ease of measuring, and sub-35,000 PSI pressures-- Reloder 7 is yet another excellent choice for 300 grain projectiles in the Savage 10ML-II. The accuracy speaks for itself; the recoil of this specific load due to high muzzle pressure and the heavy charge weight can be tamed a bit by use of a loading from 60 - 62 grains, a more comfortable area according to shoulder.
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© 2005 by Randy Wakeman
