Re: US869, 200 Accubond, 300RUM starting charges?
I picked up 8lbs of US869 and played with it last week over in MT. So this is a follow up to let folks know what I found with this combination.
Essentially, I found that US869 is allowing me to get another 100fps or so out of this combination of powder, bullet and rifle. The max load that I am comfortable with is right above 3200fps with the 200g Accubond and I'm actually getting less in the way of pressure signs that I got at 3100 with Retumbo and RL-25. I'd started at 96 gr. and had loaded in .5g increments to 108.5. I quickly worked up to 108.5 and have settled on a load in the 109 to 109.5 range that's doing over 3200fps. I keep all the loaded ammo in the fridge overnight and in cooler at 40 degrees when shooting to try and simulate elk hunting conditions. A couple of the mornings I was shooting at ele., there was frost before the sun hit where I was shooting.
I had been using a low quality chrono this last week over in MT so that I'm not real confident of my ES, ave. etc., but I should be able to fly a few over the Oehler pretty soon and get a better idea of whats going on. I did shoot out to 700, but in bad conditions and w/o knowing my clicks because I didn't have a computer. So, I just worked it out by shooting a few and put in a few elk killers at that distance off a crappy rest and gusty winds, but I've still got quite a bit of testing and practice to do to feel comfortable shooting an animal at that distance with this load.
In terms of accuracy, things seem to be going quite well. I shot off a crappy rest most of the week and was getting sub MOA, but that was as good as I could hold as well. When I got to the Deep Creek range and had a real bench and shooting of shot bags, my groups plummeted into the .3s at 100yds. By the time I had a chance to reach out to 500+ there, gusty side winds kicked up and groups opened up to over MOA. So, I really haven't had the ideal conditions to see what this can do at some longer distances. I'd been worried that too slow a powder might make the pressure curve destroy accuracy, but at 100yds, this hasn't seemed to be the case anyway.
A couple of observations that I noted with this slower powder is that the entire barrel seemed to warm up after shooting 3-4 rounds. The heat from other powders I've shot seemed to be much more concentrated around the throat and a bit forward from there. Perhaps this is evidence of it's slowness? Cleaning was a cinch--seemed to clean up faster than other powders I've tried in this rifle. Meters very nicely, of course.
Edit: I don't know if others have found this to be the case with this powder, but so far there's and indication that the first 2-3 shots from a cold, clean barrel are really wild--much more so than any other powder I've dealt with and I'm not sure that this is the powder's fault, but am at a loss of how else to explain it. I did shoot nice groups to the same POI with a cold dirty barrel and this is how I hunt. After the first 3 or 4 with a clean barrel, groups and POI (full floated barrel) seemed very tight at 100yds.
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