Shooting new 6.5x84 Savage barrel, question about target results?

[skoger]

Hey guys. I just took a older long action, stagger feed 30/06and put on a new unfired 6.5x284 matte sporter barrel. I did nothing to the action, or gun, except adjusting the 3 screw trigger, and floated the older Choate stock it was in. I am shooting 120Sierra SP, at 3380fps thru my Bench 6.5 x 284 with 30" barrel, using this laod. I took 10 shots to zero 2 inches high at 100, let cool a few minutes, then shot a 5 shot group,slowly, no break in, .628, center to center, horizontal group. Now the stock is not that conducive to good accuracy being narrow. I was shooting across my tool box, on V sandbags. I then drove across my field, to a red clay bank, 295 yards lasered. I picked up 2 white rocks, about 4" in diameter and drove back to the original spot, took 2 shots, nailed the first one about 3/4 of the way to the top, took off a hunk, second I held a little low, dead center! I am building this as a strictly deer hunting rig, so I figure good to go! I did notice some small grey tails, looked like pencil marks beside each bullet hole, any suggestions as to what this is?

[Dennis]

Which bullets are you using? The marks may be from the bullet jacket. The bullet may be breaking up before penetrating the rock.

JMO

[skoger]

I dropped the load back 1/2 grain, no more comet tails, short a little tighter group!