I shot a couple of Audette series (?)yesterday, clocked with a LabRadar rather than shot at distance, and I am a little surprised at the results. Hoping for a few comments!
The gun is a Tikka Sporter, with a 24" barrel varmint profile barrel chambered in .260 Remington. Shot off a Caldwell Rock BR front rest and a bunny ear rear bag, shimmed up with a donut bag and a home-brew platform to boost the rear rest up to fit in the scoop in the butt stock. Bushnell 4.5-30 Elite Tactical scope set at about 25x, trigger adjusted down to about 2.2 pounds, shot indoors at about 95 yards at about 65 degrees.
The load used 142 grain Sierra MatchKings, H4350, virgin, neck-turned, weight sorted Lapua brass, and Winchester WLR primers. I loaded a series from 41.5 grains to 44.5 grains in 0.3 grain increments, and a second series from 41.4 grains to 44.5 in 0.3 grain increments. Bullets were seated 0.010" off the lands.
I wasn't going to type in the detailed results, but since I started the thread I figured I should do it right! Format is charge weight, followed by velocity in fps, with the difference in velocity from the next charge on the following line.
41.5 2,601
31
41.8 2,632
39
42.1 2,671
-20
42.4 2,651
29
42.7 2,680
51
43.0 2,731
-50
43.3 2,681
54
43.6 2,735
17
43.9 2,752
17
44.2 2,769
81
44.5 2,850
The second series clocked as follows:
41.4 2,616
18
41.7 2,634
22
42.0 2,656
-10
42.3 2,646
54
42.6 2,700
28
42.9 2,728
-42
43.2 2,686
63
43.5 2,749
14
43.8 2,763
50
44.1 2,813
-25
44.4 2,788
Both series shot into one ragged hole for each series (each measuring 0.58" less a couple of clunkers), with very little horizontal dispersion and not much more vertical dispersion (again, shooting was done at only about 95 yards). Three extra rounds loaded with 43.5 grains shot an honest 0.37" group, if I can call a three-shot group from a varmint profile barrel "honest"!
I think I am seeing an accuracy node between about 42.0 grains and 42.4 grains (about 42.2 grains), and a second node at about 42.9 grains to 43.3 grains (about 43.1 grains).
I am suspicious because I seem to be seeing two distinct accuracy nodes only 0.9 grain apart. Is this normal?!?!
I intended to shoot some groups to confirm the results and fine tune the seating depth, but I am not sure whether I should bracket each alleged node separately, or that whole area!
I am leaning toward shooting some groups at 42.0 grains to 42.4 grains, and a few more at 42.9 grains to 43.3 grains.
Any help will be greatly appreciated!!! Thank you all and sorry this went on so long!!! I figured it was better to get as much detail as I could provide up front, in one place!!!
_
The gun is a Tikka Sporter, with a 24" barrel varmint profile barrel chambered in .260 Remington. Shot off a Caldwell Rock BR front rest and a bunny ear rear bag, shimmed up with a donut bag and a home-brew platform to boost the rear rest up to fit in the scoop in the butt stock. Bushnell 4.5-30 Elite Tactical scope set at about 25x, trigger adjusted down to about 2.2 pounds, shot indoors at about 95 yards at about 65 degrees.
The load used 142 grain Sierra MatchKings, H4350, virgin, neck-turned, weight sorted Lapua brass, and Winchester WLR primers. I loaded a series from 41.5 grains to 44.5 grains in 0.3 grain increments, and a second series from 41.4 grains to 44.5 in 0.3 grain increments. Bullets were seated 0.010" off the lands.
I wasn't going to type in the detailed results, but since I started the thread I figured I should do it right! Format is charge weight, followed by velocity in fps, with the difference in velocity from the next charge on the following line.
41.5 2,601
31
41.8 2,632
39
42.1 2,671
-20
42.4 2,651
29
42.7 2,680
51
43.0 2,731
-50
43.3 2,681
54
43.6 2,735
17
43.9 2,752
17
44.2 2,769
81
44.5 2,850
The second series clocked as follows:
41.4 2,616
18
41.7 2,634
22
42.0 2,656
-10
42.3 2,646
54
42.6 2,700
28
42.9 2,728
-42
43.2 2,686
63
43.5 2,749
14
43.8 2,763
50
44.1 2,813
-25
44.4 2,788
Both series shot into one ragged hole for each series (each measuring 0.58" less a couple of clunkers), with very little horizontal dispersion and not much more vertical dispersion (again, shooting was done at only about 95 yards). Three extra rounds loaded with 43.5 grains shot an honest 0.37" group, if I can call a three-shot group from a varmint profile barrel "honest"!
I think I am seeing an accuracy node between about 42.0 grains and 42.4 grains (about 42.2 grains), and a second node at about 42.9 grains to 43.3 grains (about 43.1 grains).
I am suspicious because I seem to be seeing two distinct accuracy nodes only 0.9 grain apart. Is this normal?!?!
I intended to shoot some groups to confirm the results and fine tune the seating depth, but I am not sure whether I should bracket each alleged node separately, or that whole area!
I am leaning toward shooting some groups at 42.0 grains to 42.4 grains, and a few more at 42.9 grains to 43.3 grains.
Any help will be greatly appreciated!!! Thank you all and sorry this went on so long!!! I figured it was better to get as much detail as I could provide up front, in one place!!!
_
