Thanks for the welcome. I don’t visit often because other calibers and family (mostly) has distracted me for years. I found this thread during some powder research for medium-weight 300blk, because I have a lot of the 125 NBT and 150 SST from seconds sales years ago. I then got motivated to do this test to backup my statement that Socom is a good powder for 125 grain projectiles.dellet wrote: ↑Tue Aug 09, 2022 10:07 pmBefore it was Socom, I’m pretty sure it was Lovex D063-01. A canister grade powder. SW Blackout is D063-02 and supposed to be 1680.attila. wrote: ↑Tue Aug 09, 2022 4:26 pm
Thanks for the reply. I agree. I did expect some pressure signs, as finding reasonable max in my barrel with my component combination was a purpose of my test.
The big surprise was a popped primer at an entire grain less powder than the SW manual max load, which they say is <55,000 psi. You're right, that 0.080” deeper seating depth with the 150 SST on top of the other factors can change things much more drastically than I thought.
Another thing that might be contributing to signs is excess headspace. I had that happen in 277WLV. I had pressure signs at much lower velocities than others were seeing from the same combination. After some enlightening conversations, I changed from full length sizing with 0.012” shoulder bump to more carefully sizing just 0.002-0.003”, and signs went away. That was a very cool revelation! I haven’t had the chance yet today, but I do intend to compare a fire-formed case to the primed brass that I am using (still using what I primed in 2014 cuz I shoot so little).
Thanks again!
I got some D063-01 real early and Plant One had a source that was a commercial loader. A few others got ahold of some also. The consensus was that it was a pretty hot 1680, you needed to drop about a grain using 1680 data. You might compare your results to some of those loads and see if that stacks up.
Way back in time I did a thread called Extreme Blackout. Detailed my brass prepping and gas systems. Basically running bolt action pressures with out ejector smears and extractor marks. A huge portion of that was minimal resizing of the brass like you are doing. It increases case capacity just over 1 full grain, about 5%. That’s huge.
2000 fps from a 10” barrel is pushing it hard, primer pockets don’t last long
Good to see you visit again. Not too many of the old crowd checking in
Yeah, I also found Socom to be notably faster than Blackout during my 277WLV experimentation. With a 90 grain bullet, it takes around 2 grains less (22 vs 24) powder for the same velocity. Socom sitting so nicely in between H110 and 1680 is why I didn’t bother trying Blackout or the very similar 1680 with the 125 NBT especially.
With regard to the 150 SST, my self-imposed max is a bit under 2000 fps, so hopefully the primer pockets last at least a couple of firings. I’m just bummed that 300BLK can’t push the 150 SST fast enough to get great expansion (allegedly). Not being able to find enough expansion data or tests at 300BLK speeds, I’ve been thinking about doing water jug, wet newspaper, and/or maybe home-made gelatin to see how they actually behave. I don’t usually have enough time in the day, so I can’t promise anything. It’s also low priority due to having plenty of better options to go hunting with.