Hondo64d
Well-Known Member
Just starting to play with my 22-250. 700 action trued by Beanland and an 8" twist Bartlein 2b barrel pillar bedded in a Manners EH3. Looked through the manuals to see what burn rates were appropriate for this combo. I didn't see 7828ssc listed but saw several in that burn rate range so thought I would give it a try.
In short, I don't think 7828ssc is the powder for the 22-250 with 75r Amaxes. I loaded and shot 8 different charges in .4gr increments starting with 35.2gr and ending with 38gr. Bullets were seated to lightly kiss the lands. Runout was extremely low, with most being < .001" (gotta love Lapua brass!). I got one group that was about .5 MOA and two groups that were in the .6 MOA range (5 shots at 300 yards) but the rest weren't very good and the highest two charges quite awful, approaching 2 MOA. It was interesting that with the highest three charges, the velocity nearly quit climbing, with averages increasing less than 7 fps with each .4gr. increase in powder. Max average velocity with 38gr. was 3139. Extreme spreads were not very good and some quite bad. The higher charges had extreme spreads as high as 67 fps.
Next I tried H4350. I started at 34.8 and went up to 36.4 in .4gr increments. Groups got progressively tighter as the charges increased and extreme spreads decreased. Best group was at 36.4gr with four of five being in about .4" and a flyer that opened it up to about .8". That one averaged 3210 fps. Bolt lift was getting a little harder at 36.4gr but primers looked good and no ejector hole marks. I was encouraged by all the different charges hitting the same POI. If you stacked all five targets on top of one another, the entire 25 shots would be less than two inches. Were it not for the lowest charge, they all would have gone into about 1.25". Extreme spreads were much better than with 7828ssc but still not nearly as good as I would like, with the top two charges showing 38 and 39 fps extreme spreads. I think I'll bump it up to 36.6 and see what it does.
If I don't see what I'm looking for, I'll move on to R15.
John
In short, I don't think 7828ssc is the powder for the 22-250 with 75r Amaxes. I loaded and shot 8 different charges in .4gr increments starting with 35.2gr and ending with 38gr. Bullets were seated to lightly kiss the lands. Runout was extremely low, with most being < .001" (gotta love Lapua brass!). I got one group that was about .5 MOA and two groups that were in the .6 MOA range (5 shots at 300 yards) but the rest weren't very good and the highest two charges quite awful, approaching 2 MOA. It was interesting that with the highest three charges, the velocity nearly quit climbing, with averages increasing less than 7 fps with each .4gr. increase in powder. Max average velocity with 38gr. was 3139. Extreme spreads were not very good and some quite bad. The higher charges had extreme spreads as high as 67 fps.
Next I tried H4350. I started at 34.8 and went up to 36.4 in .4gr increments. Groups got progressively tighter as the charges increased and extreme spreads decreased. Best group was at 36.4gr with four of five being in about .4" and a flyer that opened it up to about .8". That one averaged 3210 fps. Bolt lift was getting a little harder at 36.4gr but primers looked good and no ejector hole marks. I was encouraged by all the different charges hitting the same POI. If you stacked all five targets on top of one another, the entire 25 shots would be less than two inches. Were it not for the lowest charge, they all would have gone into about 1.25". Extreme spreads were much better than with 7828ssc but still not nearly as good as I would like, with the top two charges showing 38 and 39 fps extreme spreads. I think I'll bump it up to 36.6 and see what it does.
If I don't see what I'm looking for, I'll move on to R15.
John
