Adventures in 300 Win Mag with non-cannister powder

[sqlbullet]

Many years ago I bought some non-cannister WC-872 powder from pats reloading. I have around 16 lbs of the stuff and had always planned on using it in 300 Win Mag.  It has proved too slow for 168 grain and 180 grain bullets.  I held out hope for heavier bullets.

A few years later I picked up 1000 30 cal 240 grain Sierra Matchking seconds.  240 grain bullets generally need a 1:9 twist to stabilize and I have a 1:10, but some guys reported success so I figured I would test.

In general the consensus was that WC872 is slow enough that you can't make an over-pressure load.  Kinda like 2400 in 10mm;  enough powder to be dangerous and you can't seat a bullet.

To that end I determined the max compressed charge I could fit in a 300 win mag and then reduced about 5% for a starting load.  My work up was 80.5, 81.5, 82.5 and 83.  I also determined that 2750 fps was the max velocity. Referencing similar powders (H870, Retumbo, US869) I expected my 80.5 grain load to produce about 2400 fps, and I hoped that my max charge of 83 grains would get to 2650-2700 fps, but wasn't confident.  I loaded those in 2017.

I finally got to test them last Saturday.

First shot of 80.5 grains went 2746 fps.  Shots two and three were a bit slower, and then shot four spiked to 2796 fps, and had a sticky bolt and hard extraction.  I didn't shoot the fifth shot.  Despite the one shot blowing the SD/ES, I had a 0.5" three shot group and a 1.5" total group at 100 yards.  Most significantly none of the bullets showed any evidence of keyholing or instability.

I spent Sunday evening unloading the rest of this ammo wth my RCBS kinetic puller, and then loaded up a new test batch starting at 75 grains with a max load of 79.5. I hope to test them one night this week.

While I was a little bummed about pulling ammo, I am very excited to have a bullet/powder combo that will be near max with my powder. I am also now hopeful that I can find a load for my 260 Remington with this powder with some very heavy 6.5 projectiles.

[The_Shadow]

Hey Mitch if you don't mind could you take a picture of the WC872 powder in a scale pan close up.
I'd like to add it to my powder picture files...

[sqlbullet]

Will do.  It will be later tomorrow or Sunday as I am away from home at the moment.

I actually have about 4-5 non-cannister powders.  I will get pics of all of them for you.