7mm Mag load data needed

[cdoc42]

CAUTION: The following post (or a page linked to) includes or discusses loading data not covered by currently published sources of tested data for this cartridge (QuickLOAD or Gordon's Reloading Tool data is not professionally tested). USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assumes any liability for any damage or injury resulting from the use of this information.

Does anyone have any loading information using US869 powder with a Large Rifle Magnum primer and Hornady 162gr ELD-X bullet?

I currently successfully used that powder and primer with the Hornady 162gr spire but I don’t want to assume I can safely transfer the data to the ELD-X bullet.

I added the required disclaimer so it applies to me as the user of the information at my own risk:

 

[HiBC]

I don't knpw anything about US 869.

The reloading powder we can buy off the shelf is tested and adjusted to a narrow range of performance.

An ammunition producer can buy a rail car size lot of a powder like US 869 and test it. They can determine with "X" brass and "Y" chamber for 2700 fps at 58,000 psi for this train car and only this train car we load 58 gr.
Next train car we might use 55 gr or 62 gr ,but there is opportunity for testing and control. My tin foil hat tells me SOME lots of powder just don't behave properly. Maybe it gets sold cheap with no support but a disclaimer.

If you buy powder cheap this way,buy a bunch then go your own testing. No one on the internet can do that for you. Assume they bought from a different rail car.
Its not like buying another lb of H-4350 SC

 

[GeauxTide]

Hornady doesn't list separate data for different configurations of the same weight. You can safely use the charges you tried. I only found 162 SPBT Hornady data, beginning with 77.0 grains. Win Cases, Win Mag Primers.

 

[cdoc42]

I had great groups in the past with H870 - a military surplus sold by Hodgdon. Apparently when the supply ran out, so did the existence. Ultimately, US869 came about, with a very slow burn rate compared to others at the time:

In the past, H870 was 106 out of 106 powders listed, then 145 out of 149 (Retumbo was 142). Currently, the latest list that I have has 175 powders - Retumbo is 164 out of 175 and US869 is 173 out of 175.

So US 869 is still closest to the end of the slowest powders over time .

I had success with 78 gr of H870 with 162 gr Horn BTSP. I had the same success with US869 at 78 gr. Both have a max of 80 gr.

But the shape and length of the 162 gr ELD-X draw me to caution to extrapolate that 78 gr would be as safe. I could experiment, but I'm just asking to save myself time and $$ since 7000 gr of US869 only gives me 89 rounds at 78gr. at over $40 a pound with tax.
That will cost me just under one buck a round to experiment.

 

[Unclenick]

Just back down to the starting load and seat the bullet to produce the same bullet jump to the lands. The longer bullet will take up a bit more space in the case, but the case is big enough that it shouldn't drive pressure too high for a starting load.

If you can't seat the bullet deeply enough to keep the jump to the throat the same as you had before, then back down another five percent from the listed starting load just to be extra safe, but I doubt you will have to do this.