New 10" barrel, bullet stability problems

[snipecatcher]

UPDATE WITH NEW BARREL ON PAGE 8




I just got my 10" barrel in 300 BLK, and I've taken it to the range yesterday and today. It's an 8 twist with TP555's adjustable gas block, which is very well made, by the way. Day 1, I loaded up some supersonic rounds and subsonic. The subsonics were loaded with 208 A-max's and VV-N110 powder.

10 grains = 1200 fps
9.0 grains = 1100 fps
8.5 grains = 1000 fps

None of these loads were stable at 100 yards. They weren't completely key-holing, but groups were in the 5" range and the holes were oblong.

Today, I took out some new loads. These consisted of supersonics once again, and some subsonics loaded with 240 SMK's and VV-N110.

9.4 grains = 1120 fps
9.0 grains = 1080 fps
8.6 grains = 1050 fps

Once again, none of these loads were stable. Slightly oblong holes, groups in the 4" range.

I had an 18" Shilen 8 twist before this and it shot the 208's and 240's just fine, no stability problems. I'm not sure where to go from here, does anyone have any suggestions?
Regards,
-Dan