I figured I'd share my most recent load development after tweaking a few things in my loading process. The initial ladder and testing was done Monday afternoon/evening with temps reading mid-low 90's, and confirmation done Tuesday evening with the temp right at 80.
First the ladder over the Magnetospeed. This was fired after allowing the rounds to warm up to outside temperature (91 degrees) for 1/2 hour in the shade and after 3 rounds of Hornady ammo to warm the barrel up. 1 minute intervals between rounds.
And then three rounds of 41.4gr testing the first node. The velocity is just over 20fps lower because they came out of a 65 degree basement, I didn't let them warm up because I didn't want the barrel to cool all the way down.
I ended up choosing the 42gr node which had an ES of 3 and shot this yesterday evening after warming my scale up and recalibrating it to confirm the weight was still good before loading for a match. The barrel and ammo were both 65 degrees which is why I shot 4 instead of 3 and why the first went low at 2685.
Lastly my worst case scenario test with 1 round at the correct charge weight (42.0gr) spray with water to test for pressure in rain, and 2 rounds at 41.96gr and 2 rounds 42.04gr. These were done on a cool barrel at around 80 degree outside temp and 65 degree ammo. The 42.0gr sprayed with water was the faster round at 2711 as well as the first round of the string. Between inspecting the piece of brass closely for pressure and pulling the bolt to swab the chamber, the other rounds had a few extra minutes to warm up, had everything been the same temp and warm barrel I fully expect the wet round would have been a good 10-15fps higher than it was. Normally I'd test this again and/or test with more rounds but I only started with 250 pieces of this brass to do load development and be able to have 200 rounds to confirm zero and shoot the match so I had to cut it short.
Accuracy is in the .4's @100 which I attribute to being new brass with .003"-.004" runout but that's plenty acceptable in my book and will tighten up once it's fired. I saw a little better accuracy with the 100 pieces of Lapua brass I tested on it's first firing which had a little tighter runout, but the Lapua ES and SD's where just so-so at 8-9. Not that SD's of zero are the norm but I generally have no issue getting SD's of 5 or under on new brass, single digit SD's are still good though. I'll take a .1" increase in group size if it means half or less ES's and SD's.
The only negative aspect that I see from this is that I can't blame any misses on the load. It works cool, it works hot and it works wet.
First the ladder over the Magnetospeed. This was fired after allowing the rounds to warm up to outside temperature (91 degrees) for 1/2 hour in the shade and after 3 rounds of Hornady ammo to warm the barrel up. 1 minute intervals between rounds.
And then three rounds of 41.4gr testing the first node. The velocity is just over 20fps lower because they came out of a 65 degree basement, I didn't let them warm up because I didn't want the barrel to cool all the way down.
I ended up choosing the 42gr node which had an ES of 3 and shot this yesterday evening after warming my scale up and recalibrating it to confirm the weight was still good before loading for a match. The barrel and ammo were both 65 degrees which is why I shot 4 instead of 3 and why the first went low at 2685.
Lastly my worst case scenario test with 1 round at the correct charge weight (42.0gr) spray with water to test for pressure in rain, and 2 rounds at 41.96gr and 2 rounds 42.04gr. These were done on a cool barrel at around 80 degree outside temp and 65 degree ammo. The 42.0gr sprayed with water was the faster round at 2711 as well as the first round of the string. Between inspecting the piece of brass closely for pressure and pulling the bolt to swab the chamber, the other rounds had a few extra minutes to warm up, had everything been the same temp and warm barrel I fully expect the wet round would have been a good 10-15fps higher than it was. Normally I'd test this again and/or test with more rounds but I only started with 250 pieces of this brass to do load development and be able to have 200 rounds to confirm zero and shoot the match so I had to cut it short.
Accuracy is in the .4's @100 which I attribute to being new brass with .003"-.004" runout but that's plenty acceptable in my book and will tighten up once it's fired. I saw a little better accuracy with the 100 pieces of Lapua brass I tested on it's first firing which had a little tighter runout, but the Lapua ES and SD's where just so-so at 8-9. Not that SD's of zero are the norm but I generally have no issue getting SD's of 5 or under on new brass, single digit SD's are still good though. I'll take a .1" increase in group size if it means half or less ES's and SD's.
The only negative aspect that I see from this is that I can't blame any misses on the load. It works cool, it works hot and it works wet.
