As the title states, I am looking for opinions on my load development results from this weekend. Before starting development I put about 180 rounds of FGMM 77gr and Norma Match 77gr through it and both shot well, averaging around 1/2 MOA.
For my load development I used virgin lapua brass, 75 ELD-M bullets, varget and CCI #400's. The virgin brass was run through an expander die to leave approximately .002" neck tension. Then it was trimmed to 1.750" (some were under, and were not trimmed), then chamfered/deburred. I charged from 23.0gr to 25.1gr in 0.3gr increments, and loaded the bullets to a COAL of 2.410" which is roughly .020" off the lands in my chamber.
Here are the results. Each group is 3 shots, fired from 100 yards. I included each groups velocity AVG, ES and SD.
I think my next step will be to explore further around 24.5-24.8gr, but I am curious as to others' opinions. I am a bit disappointed to see such high ES and SD with some of the groups, as I was regularly achieving mid single digit SD's with my 308 hand loads. I am not overly concerned though because I think it might be partially due to the virgin brass and the clean necks which I think can contributes to inconsistent bullet release. The node around 24.5gr seems promising as it is pretty much where I want to be with velocity right around 2800, and was clearly accurate.
As for pressure signs, I didn't notice much of anything through the work up. Primers were flattened a bit even from 23.0gr but I think this may be partially caused by the virgin brass being a bit loose in my chamber and the fact that some of the primers were a few thou proud of the case head (should have uniformed the pockets first, but will do so next loading). I will keep an eye on that, but other than that I didn't notice anything, all loads extracted easily and there were no swipes or other marks on the brass. I did have one additional round that was loaded to 25.4gr that isn't shown in the picture. Its velocity was near 2900 and again, no real apparent pressure signs. Also noted, charge weights 23.3gr and up were all compressed loads at this COAL. There were loaded with a standard funnel, and I am going to try with an extended drop tube to see if I can reduce the compression a bit.
Let me know what you guys think, what your opinions are for the next stage of development, etc. Thank you.
For my load development I used virgin lapua brass, 75 ELD-M bullets, varget and CCI #400's. The virgin brass was run through an expander die to leave approximately .002" neck tension. Then it was trimmed to 1.750" (some were under, and were not trimmed), then chamfered/deburred. I charged from 23.0gr to 25.1gr in 0.3gr increments, and loaded the bullets to a COAL of 2.410" which is roughly .020" off the lands in my chamber.
Here are the results. Each group is 3 shots, fired from 100 yards. I included each groups velocity AVG, ES and SD.
I think my next step will be to explore further around 24.5-24.8gr, but I am curious as to others' opinions. I am a bit disappointed to see such high ES and SD with some of the groups, as I was regularly achieving mid single digit SD's with my 308 hand loads. I am not overly concerned though because I think it might be partially due to the virgin brass and the clean necks which I think can contributes to inconsistent bullet release. The node around 24.5gr seems promising as it is pretty much where I want to be with velocity right around 2800, and was clearly accurate.
As for pressure signs, I didn't notice much of anything through the work up. Primers were flattened a bit even from 23.0gr but I think this may be partially caused by the virgin brass being a bit loose in my chamber and the fact that some of the primers were a few thou proud of the case head (should have uniformed the pockets first, but will do so next loading). I will keep an eye on that, but other than that I didn't notice anything, all loads extracted easily and there were no swipes or other marks on the brass. I did have one additional round that was loaded to 25.4gr that isn't shown in the picture. Its velocity was near 2900 and again, no real apparent pressure signs. Also noted, charge weights 23.3gr and up were all compressed loads at this COAL. There were loaded with a standard funnel, and I am going to try with an extended drop tube to see if I can reduce the compression a bit.
Let me know what you guys think, what your opinions are for the next stage of development, etc. Thank you.
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