Post by mosigdude on Jun 16, 2015 8:42:57 GMT -8
I made it out to the range yesterday to work out a few loads for the 6.5x6.8. I previously had less-than-stellar luck with most of the bullets I tried in the 120-123gr range. My barrel is a 22" 1:9 twist, standard profile, target crown. After doing some measurements and speculation, I decided that my barrel was possibly better suited to some of the 100gr projectile options. Today I worked with the 100gr Nosler Ballistic Tips. All were seated at magazine length of 2.300" which still gives a pretty lengthy .080" jump to the lands in my chamber. Everything was trimmed slightly short at 1.670" and all brass was once-fired (after form) Federal pull-down 6.8SPC brass. I used a .289 neck bushing in a redding S-Die for about .004" neck tension, Cases were full-length sized and the shoulder bumped back about .004" less than fired-case dimensions. I previously did a quick check for pressure signs and settled on ladder testing top-end data listed for the 6.5 Grendel using CFE223 and Benchmark (in other words, I didn't START here but worked up to these loads from lower, today I tested only the top-end loads that I had previously decided to be safe in my particular rifle)
Today was 79 degrees F, and wind varied from dead still to an occasional gust of 10mph or so. I tried to shoot only when the wind was still but I don't have wind indicators on my range so the usual disclaimer of who knows what's going on downrange. All targets were 200 yards for load-development and I shot 2 strings of 3-shot groups of each load combination. I will later take the best of these, do a bit more refinement and shoot some 5-shot groups at different temps.
Both load tests were consistent and shot exceptionally well!
My largest group with CFE223 was just a touch over 1.5" and my best 2 were 0.38" (2836fps avg) and 0.42" CTC.
Benchmark produced excellent accuracy as well, my largest group of the day was 0.88" and best 2 were 0.37" and 0.57", both in the mid 2700's for velocity.
Thank you BHW for another 1/4 MOA rifle, and with a hunting-class bullet none-the-less!! This rifle is about to get paint!
Today was 79 degrees F, and wind varied from dead still to an occasional gust of 10mph or so. I tried to shoot only when the wind was still but I don't have wind indicators on my range so the usual disclaimer of who knows what's going on downrange. All targets were 200 yards for load-development and I shot 2 strings of 3-shot groups of each load combination. I will later take the best of these, do a bit more refinement and shoot some 5-shot groups at different temps.
Both load tests were consistent and shot exceptionally well!
My largest group with CFE223 was just a touch over 1.5" and my best 2 were 0.38" (2836fps avg) and 0.42" CTC.
Benchmark produced excellent accuracy as well, my largest group of the day was 0.88" and best 2 were 0.37" and 0.57", both in the mid 2700's for velocity.
Thank you BHW for another 1/4 MOA rifle, and with a hunting-class bullet none-the-less!! This rifle is about to get paint!