Clear Seating Depth Signal

[CharlieNC]

With the windy hurricane effects, it was not the best day for testing but I had not been shooting for two weeks so i had to go anyway. Working on loads for the 223 Remage FTR rifle I just put together, the powder nodes have been identified. Four rounds each were loaded at .010, .015, and .020 inches jump for the 69SMK which have always shot the best groups for me at midrange. At 300 yards I shot all these pretty quickly during a lull in the wind, and through the scope I could see the trend clearly emerging.

For .010" three shots were horizontal at 1.6", and the fourth led to 0.9" vertical. Group 1.7"
For .015" three shots were vertical at 1.8", and the fourth led to 0.7" horizontal. Group 1.8"
For .020" the vertical was 1.0", horizontal 0.6", three shots in a 0.6" group and the fourth led to a 1.0" group.
The point of impact was the same for all, which has not always been the case.

It was interesting to watch the transition from a horizontal string to a vertical string to a clustered group. Maybe I will continue by increasing the seating depth to find what trends follow.

 

[dkhunt14]

On some guns and different bullets I see the size and shape of the group change with seating depth. Some combinations show better then others. I also believe it shows better at distance.. Matt

 

[barefooter56]

CharlieNC,
The .020 off the lands has real good indicators. When its that windy and you don't have time to "pick" your testing day(s) I look at the vertical spread. The horizontal is just a "weather report". Don't lose that information and test it at 2-300 and out to see if vertical stays low. ( 1 MOA or less is worth trying for). However! As the range increases small things like cheek pressure , tense shoulder vs soft shoulder ETC. Will affect how the rifle recoils and can induce more vertical than the load actually indicated during testing. Its us "loose nuts behind the butt-plate that can screw up the detail faster than anything! lol !!

 

[CharlieNC]

You are exactly right Phil. After a bit of due diligence working up a decent load, I am sure that I am the cause when a shot is not in the group. And like you say I can usually identify that because the recoil management is not just right. This weekend will be different at the long range match, and I can't wait to see how much I mis-judge the wind.