User4302021
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- Mar 17, 2018
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I was able to get my hands on 4lbs of the new Enduron 8133 powder from IMR. Component list includes: Lapua fire formed brass, Fed 215M primers and Berger 300 grain OTM's.
Yesterday I was able to get out to the range and fire the very first loads. The temperature was 47 degrees and rifle and ammo were allowed to assume ambient temp before firing as verified by an infrared thermometer.
Working up in 1g increments from 100g I got to 105g before the primers just began to flatten. Out of my 36 inch barrel I was getting 3056fps recorded with a magnetospeed chronograph. I believe I should be able to hit 3100fps with plenty of head room for hotter weather. I'll update as groups come together.
Update: It is 42 degrees here today, I took out some more loads using 300 grain Berger Hybrids. I changed the seating depth in the Lapua brass to 3.892" COL, Previously it was at 3.826" but in reading up on Mr. Allens testing with RL33, I learned that he used 3.865" as his COL. Using a Hornady tool to measure touch depth, I determined that 3.892" would be 70 thou off the lands. This puts the boat tail / bearing surface junction right at the base of the neck also.
All in a 36" barrel:
105.5 grains gave an average velocity of 3099 fps but vertical was horrible (2 MOA), pressure was under max. Primers were just beginning to flatten. Group center was 1.42 cm below aiming point. SD was 22 fps.
106 grains gave an average velocity of 3114 fps. Vertical tightened up to less than 1 MOA. Group center was 3.6 cm above aiming point and round. Primers were flat, but not too flat. SD was 12 fps.
106.5 gave an average velocity of 3133 fps. Vertical still less than 1 MOA. Group center was 4.3 cm above aiming point. Primers were appropriately flat, not too flat. SD was 13 fps.
This area of 106 grains is exactly where Kirby Allen stopped with RL33 as it gave him 100% load density. His speed out of a 28" Lilja was a reported 3036 fps. That was back in 2013, pre-magnetospeed and pre-Labradar days, so I take those velocities with a grain of salt. Even still, when allowances are made for the extra barrel length, this powder is right in the neighborhood.
All in all, I think this new powder is mirroring the burn rate of RL33, in this cartridge at least. Since it is still hovering around 40 degrees here in the climate where these loads are being worked up, I think I will stick with 106 grains and play with seating depth to fine tune. That should give me plenty of head room in the load for the hotter summer months.
Yesterday I was able to get out to the range and fire the very first loads. The temperature was 47 degrees and rifle and ammo were allowed to assume ambient temp before firing as verified by an infrared thermometer.
Working up in 1g increments from 100g I got to 105g before the primers just began to flatten. Out of my 36 inch barrel I was getting 3056fps recorded with a magnetospeed chronograph. I believe I should be able to hit 3100fps with plenty of head room for hotter weather. I'll update as groups come together.
Update: It is 42 degrees here today, I took out some more loads using 300 grain Berger Hybrids. I changed the seating depth in the Lapua brass to 3.892" COL, Previously it was at 3.826" but in reading up on Mr. Allens testing with RL33, I learned that he used 3.865" as his COL. Using a Hornady tool to measure touch depth, I determined that 3.892" would be 70 thou off the lands. This puts the boat tail / bearing surface junction right at the base of the neck also.
All in a 36" barrel:
105.5 grains gave an average velocity of 3099 fps but vertical was horrible (2 MOA), pressure was under max. Primers were just beginning to flatten. Group center was 1.42 cm below aiming point. SD was 22 fps.
106 grains gave an average velocity of 3114 fps. Vertical tightened up to less than 1 MOA. Group center was 3.6 cm above aiming point and round. Primers were flat, but not too flat. SD was 12 fps.
106.5 gave an average velocity of 3133 fps. Vertical still less than 1 MOA. Group center was 4.3 cm above aiming point. Primers were appropriately flat, not too flat. SD was 13 fps.
This area of 106 grains is exactly where Kirby Allen stopped with RL33 as it gave him 100% load density. His speed out of a 28" Lilja was a reported 3036 fps. That was back in 2013, pre-magnetospeed and pre-Labradar days, so I take those velocities with a grain of salt. Even still, when allowances are made for the extra barrel length, this powder is right in the neighborhood.
All in all, I think this new powder is mirroring the burn rate of RL33, in this cartridge at least. Since it is still hovering around 40 degrees here in the climate where these loads are being worked up, I think I will stick with 106 grains and play with seating depth to fine tune. That should give me plenty of head room in the load for the hotter summer months.
Thanks for sharing load data.
