I am going crazy trying to work up a load for this new to me rifle. Gun has roughly 250-300 rds down the pipe. Previous owner gave me 2 targets that are one hole groups at 100 yds. Rifle is rem short action, krieger barrel 26 in, mcm a5 that's bedded. My components are h4350, 140 amax, fed 210 primers, rem cases. I shot a ladder from 40 to 45.5 at 300 yds. I saw a slight ejector mark at 45.5. I then made up 4 rounds of each 43.5, 44, and 44.5
Ladder results
chrono 15 ft temp 60
40 2614
40.5 2656
41 2666
41.5 2726
42 2732
42.5 2772
43 2824
43.5 2855
44 2879
44.5 2898
45 2936
45.5 2949 slight shiny ejector mark
day 2
temp 71 deg
43.5 gr
1. 2807
2. 2824 grouped 1.4 inch ctc @300 yds
3. 2830
4. 2807
44 gr
1. 2873
2. 2867
3. 2824 group ~3 inches
4. 2849
5. 2842
44.5 gr
1. 2879
2. 2858
3. 2867 group > 4 inches
4. 2873
today temp 84 deg
43.5 gr
1. 2824
2. 2824
3. 2836 group 1 group size grew to ~3-4 inches
4. 2818
5. 2807
6. 2824
7. 2824 group 3
8. 2830
Didnt fire last 2 because 3 of previous 8 had ejector marks.
43.6 gr
1. 2818
2. 2807
3. 2824 a few had light ejector marks, group ~3-4 inches
4. 2830
I cant figure out why a supposedly temp stable powder would show pressure signs when it's only 10 degrees hotter temp.
the other odd thing was that i was getting some powder residue on the shoulders of a few of the cases. I'm not positive but I think the first 2 days i was finishing up the brass the previous owner sized. Since I have an older rcbs press, I reset the depth of the dies when I got them home to bump the shell holder. Could oversizing cause the pressure signs? Im thinking that the sooty shoulder means I did oversize. would that be why my accuracy went to shit and the pressure signs developed? shouldn't the chrono show a bigger jump if pressure signs appear from the temp swing? On another note, are the cases with a faint ejector mark of to throw back in with the other brass or should I pitch them? I just would like to get back to the under 0.5 moa groups I know this rifle is capable of.
Thanks in advance for any help or insights.
Matt
Ladder results
chrono 15 ft temp 60
40 2614
40.5 2656
41 2666
41.5 2726
42 2732
42.5 2772
43 2824
43.5 2855
44 2879
44.5 2898
45 2936
45.5 2949 slight shiny ejector mark
day 2
temp 71 deg
43.5 gr
1. 2807
2. 2824 grouped 1.4 inch ctc @300 yds
3. 2830
4. 2807
44 gr
1. 2873
2. 2867
3. 2824 group ~3 inches
4. 2849
5. 2842
44.5 gr
1. 2879
2. 2858
3. 2867 group > 4 inches
4. 2873
today temp 84 deg
43.5 gr
1. 2824
2. 2824
3. 2836 group 1 group size grew to ~3-4 inches
4. 2818
5. 2807
6. 2824
7. 2824 group 3
8. 2830
Didnt fire last 2 because 3 of previous 8 had ejector marks.
43.6 gr
1. 2818
2. 2807
3. 2824 a few had light ejector marks, group ~3-4 inches
4. 2830
I cant figure out why a supposedly temp stable powder would show pressure signs when it's only 10 degrees hotter temp.
the other odd thing was that i was getting some powder residue on the shoulders of a few of the cases. I'm not positive but I think the first 2 days i was finishing up the brass the previous owner sized. Since I have an older rcbs press, I reset the depth of the dies when I got them home to bump the shell holder. Could oversizing cause the pressure signs? Im thinking that the sooty shoulder means I did oversize. would that be why my accuracy went to shit and the pressure signs developed? shouldn't the chrono show a bigger jump if pressure signs appear from the temp swing? On another note, are the cases with a faint ejector mark of to throw back in with the other brass or should I pitch them? I just would like to get back to the under 0.5 moa groups I know this rifle is capable of.
Thanks in advance for any help or insights.
Matt