Yosemite Steve
New member
Today I was going to just do a quick work up of IMR4350 behind Hornady's 180 gr. SST. I decided to kill two birds with one stone and got three as a bonus.
I was shooting my Savage 30-06.
I decided to try three seating depths to see what differences they would bring.
Because I had some big pressure issues the last time I did this with my shorter chamber and cartridges I started low and finished upper mid range.
The loads were as follows: IMR 4350 - 180 grain SST - CCI 200
Winchester brass weight sorted within .2 grains, 69.2 grains H2O
3 seating depths: 3.310", 3.320" and 3.330" - lands at 3.338"
Charges: 49.0, 50.0, 51.0, 51.5, 52.0, 52.5, 53.0, 53.5, 54.0, 54.5 for each seating depth.
You will see that I did not adjust my scope for any of the shots. My aiming point was the target at top left. I was shooting at 100 yards. Yes, it's just a 32 year old hunting rifle, not a 6.5 Creedmore.
We will start with 3.320":
3.320"
3.330"
I see that I put the velocity data sheets on the wrong pictures for 3.320 and 3.330...
The best grouping for certain was the longest of the three cartridges with the limitation that pressure was starting to appear on the primers and higher charges would be more than I want to go.
The COL of 3.320" had a nice three in one hole that put a smile on my face as I was hoping to find some glory in a safer seating depth.
The 3.310" seating depth was as bad as I care to see as far as grouping. But each shot was a different charge and I never got down to .3 grain increments.
What is most interesting is shots 3 and 4. At all three seating depths those two shots are nearly in identical positions! with the two longer seating depths shots 3 and 4 make one hole! Another two shots are 6 and 7, particularly 7, which is in the same exact spot on both longer cartridges. Now I have solid evidence backing the method so many people have told me... Start with a powder charge! Or... I might just do it this way again. In 30 rounds I found about where I want to seat my bullets. .020" off the lands...(somebody kept suggesting that!) and a powder charge of 51 or 53 grains.
Std7mag, you said it. This proved what you said! Thanks!
I was shooting my Savage 30-06.
I decided to try three seating depths to see what differences they would bring.
Because I had some big pressure issues the last time I did this with my shorter chamber and cartridges I started low and finished upper mid range.
The loads were as follows: IMR 4350 - 180 grain SST - CCI 200
Winchester brass weight sorted within .2 grains, 69.2 grains H2O
3 seating depths: 3.310", 3.320" and 3.330" - lands at 3.338"
Charges: 49.0, 50.0, 51.0, 51.5, 52.0, 52.5, 53.0, 53.5, 54.0, 54.5 for each seating depth.
You will see that I did not adjust my scope for any of the shots. My aiming point was the target at top left. I was shooting at 100 yards. Yes, it's just a 32 year old hunting rifle, not a 6.5 Creedmore.
We will start with 3.320":
3.320"
3.330"
I see that I put the velocity data sheets on the wrong pictures for 3.320 and 3.330...
The best grouping for certain was the longest of the three cartridges with the limitation that pressure was starting to appear on the primers and higher charges would be more than I want to go.
The COL of 3.320" had a nice three in one hole that put a smile on my face as I was hoping to find some glory in a safer seating depth.
The 3.310" seating depth was as bad as I care to see as far as grouping. But each shot was a different charge and I never got down to .3 grain increments.
What is most interesting is shots 3 and 4. At all three seating depths those two shots are nearly in identical positions! with the two longer seating depths shots 3 and 4 make one hole! Another two shots are 6 and 7, particularly 7, which is in the same exact spot on both longer cartridges. Now I have solid evidence backing the method so many people have told me... Start with a powder charge! Or... I might just do it this way again. In 30 rounds I found about where I want to seat my bullets. .020" off the lands...(somebody kept suggesting that!) and a powder charge of 51 or 53 grains.
Std7mag, you said it. This proved what you said! Thanks!
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