Distance off the lands - 7mm Mag Berger Classic Hunter 168s

[Dmayer]

Hey everyone, previously I posted in the reloading section about finding a load for my Howa M1500 7mm mag and the help was greatly appreciated. I narrowed my load down to the 168 grain Berger Classic Hunters with 59 grains of Accurate 4350 powder. I was able to get groupings of less than 0.7 inches at 100 yards.
I haven't shot it through the chrono yet, hopefully this week, and I will reply to this thread with the info I gather.
I would like to take it a step further and tinker with the bullet length, or distance off the lands. I loaded all of my original test loads pretty close to, at .003" off.
I would like to ask everyone how far should I vary the distance off the lands for more testing. Should I vary it .010" with each set or more, like .020"? Any help or suggestions is appreciated. Thanks!

 

[FearNoWind]

This artidle discusses Berger VLDs for determining load data but the procedure works just fine with other bullets when trying to determine seating depths.
Give it a try ....
http://www.bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/

 

[Dmayer]

FearNoWind, thanks. I am a beginner at this so bear with me. That article suggests a pretty wide range with the max around 0.130" off (jump). Do I need to have any concern with having such a huge gap? Is there anything to worry about? After looking at my bullets now, it would seem that they would look ridiculously short if I seated them 0.130" off. If it's not a big deal and everyone is doing it, that's fine, but I have to ask before I try it if there are any things to be worried about.

 

[rcoody]

FearNoWind, thanks. I am a beginner at this so bear with me. That article suggests a pretty wide range with the max around 0.130" off (jump). Do I need to have any concern with having such a huge gap? Is there anything to worry about? After looking at my bullets now, it would seem that they would look ridiculously short if I seated them 0.130" off. If it's not a big deal and everyone is doing it, that's fine, but I have to ask before I try it if there are any things to be worried about.

I did the berger jump test with both the VLD hunter and the Classic Hunter in my .308. I wanted a mag length seating depth. 5 groups of 5 seated 0.03 deeper each time.

I found the jump for the VLD. Seating depth made a huge difference in group size.

With the Classic Hunter the group size was quite consistent. Variation of less than a quarter inch best to worse. Not as tight as the VLD but certainly acceptable. three quarters to half in.

Now the VLD would put them in one hole less that 1/2". But about ever 3rd group the vld would throw a flier out there a half inch to three quarters out of the group. That could have been me or the fact that I didn't check all of the rounds for concentricity.

anyway the consistency of the classic hunter won for me.