What’s causing this group?

[brentc]

PM sent

 

[keithcandler]

Zman, seems that you have dismissed the fact that wind moves bullets, from 300-600 it can be quite a bit.

 

[keithcandler]

IDK, I have a custom 7mmRM. which shoots 0.26MOA. I use H1000, 69gr, CCI, Nosler brass, Berger 168 HVLD, 2995fps, They are custom loads because to get about 0.003 off the lands it's outside of SAMMI by about 0.1". You might want to consider COAL... get really close to the lands... While you do that, make sure you keep cartridge temp constant and consistent. At 100yds, you should shoot 1 hole. That's the goal... Have you also checked for consistent MV?

My rifle shoots the same load, one hole! I get another 100 fps with Retumbo, same seating depth....3100...load is rough on remington brass, but it is a hunting rifle, 26" barrel, .110 freebore throat.

 

[Tac-O]

I am trying to work up a load for the 180 Berger hvld in a 7mm rem mag. I shot a ladder at 660 yards and had 4 inches of vertical between 68.5, 69 and 69.5 of h-1000. I loaded up 69 grains and tested seating depth .010, .030, .050 and .070 off the lands. Tested at 300. .030 and .070 bot shot about 2.5 inches. It was fairly windy so I loaded up just the .030 and .070 off loads and tested them at 105 yds with no wind. Both shot .75 inches. The problem is I know this fun can shoot tighter. The groups show two touching and one off. It was the same for both seating depths. It happened the first time at 300 yards as well. At 300 yds there were two right next to each other and one 2.5 inches away. What would be your next step? How do I get the one round to suck in? Forgot to mention the order is 1st shot then 2nd one off and then the 3rd back touching the first. Attached are the 105 yard groups.

Load up 10 rounds of each of the two groups. Shoot a ten round group for each load, letting the barrel cool as you see fit.