Here are more results with the Savage 12 FV .223 with the Oryx chassis using the 36X single power Sightron 1-inch tube scope with a target dot reticle. The action screws were torqued to 60 in.-lbs. prior to this session to match the Oryx chassis torque specs.
This session, held in Northern Virginia at 100 yards on Friday, Aug 12nd again tested the 77 gr TMK bullets with IMR4166 powder. Temperatures on Monday were from 85 to 90 degrees from 10 AM to 2 PM with winds from 8 to 9 mph. Altitude of the range is 250 feet above sea level.

All the loads were shot using Lapua brass using Remington 7 ½ small rifle primers. All bullets were loaded to achieve a 1.361 msec. exit time (12th reflection) to stay well under Pmax using the 77 grain bullets with IMR4166 powder. The 1.361 exit time should be the sweet spot for a 26-inch 3% carbon steel barrel with a 0.040-inch recessed crown.

For this session, I loaded IMR4166 Enduron powder and 77 grain Tipped Match King #7177 bullets with the seating depths for the 77 grain bullets to achieve the a jump to the rifling – 0.030 to 0.020 – and then adjusted the seating depth by less than 0.005 thousandths to achieve the 1.361 exit time to accommodate variations in the brass trim length. As a result, all the loads are quite similar with only slight variations in seating depth and trim length.

The load description field shows the powder and charge, the O.A.L., the trim length, and the bullet exit time from the 26-inch barrel.

# Grps Load Description Bullet Weight Velocity Average Median St Dev 1 2 3 4
4 IMR4166 21.0 gr 2.342 1.749 wf 1.361 * 85/85 deg. F. Rem 7 ½ Oryx 60 in.-lbs. Sierra TMK #7177 77 2540 0.325 0.329 0.071 0.257 0.271 0.386 0.387
4 IMR4166 21.0 gr 2.339 1.746 wf 1.361 * 88/85 deg. F. Rem 7 ½ Oryx 60 in-lbs. Sierra TMK #7177 77 2540 0.246 0.252 0.015 0.224 0.249 0.255 0.256
4 IMR4166 21.0 gr 2.337 1.744 wf 1.361 * 88/87deg. F. Rem 7 ½ Oryx 60 in.-lbs. Sierra TMK #7177 77 2540 0.273 0.268 0.038 0.236 0.249 0.286 .0321
4 IMR4166 21.0 gr 2.334 1.741 wf 1.361 * 90/90 deg, F. Rem 7 ½ Oryx 60 in.-lbs. Sierra TMK #7177 77 2540 0.274 0.284 0.031 0.231 0.272 0.296 0.298
16 0.280 0.264 0.049


Today’s session started out poorly with two pretty large groups, but I managed to get things back together and settled down and shoot pretty consistently. I had shot the 12 FV 6.5mm Creedmoor right before switching to the 12 FV .223 so changing rifles and scopes might have had something to do with it.

I don’t believe the winds around 9 mph made much of a difference in the averages. They did change direction later in the session but initially were directly coming from behind the firing line. They moved to left to right towards the end of the session but never lost their velocity. There was some gusting but I didn’t notice much of an impact on the POI. My screw ups, not the wind, caused most of the dispersions.

The results weren’t terrible but there was a definite difference between the first two larger groups in the .380s and the rest of the session with the .223. Loads were basically all the same so I blame most of the variations on the shooter, not the conditions. I tend to have to fight to get myself to concentrate and then I concentrate less as the session wears on and I gain confidence and become complacent.

For this session, the 12 FV averaged 0.280 for 16 groups, even with the two groups in the high .380s. The last session on Aug 2nd averaged 0.364 for 16 groups and none of the groups were larger than 0.330 and no load averaged more than 0.303.


It doesn’t take much to mess up a load and session average.