TWIST, MV, STABILITY AND ACCURACY
Many years ago, Loring Hall told me that, sometimes, tipping bullets will form small groups. I have seen this often in the intervening years.
In experimenting with jacketed bullets, attempting to find out why we can’t shoot cast bullets as accurately as jacketed, testing is at muzzle velocities that show the relationship between twist, mv, stability and accuracy.
Starting at very low mv, bullets are wildly inaccurate. As mv increases, bullets then then go through the paper sideways with some accuracy, then go through the paper tipping with some accuracy, and then stop tipping.
Nosler 53 gr. Varmageddon, Titegroup, M12 Savage, Iffland 223 bbl., 14” twist, 5-shot 100 yard groups:
6.5 Titegroup, tipping, 5 shots in 7.5”.
7.0 Titegroup, tipping, 4 shots in 2.7”.
7.5 Titegroup, tipping, 4 shots in 1.15”.
8.0 Titegroup, tipping, 1 group, 1.95”.
8.5 Titegroup, tipping, 6 groups avg. 1.021”.
Hornady .22 68 gr. HPBTM, Titegroup, M12 Savage, Stevens 223 9” twist bbl., 5-shot 100-yard groups.
5.5 Titegroup, 1490 fps, tipping, 1.483” avg./3 groups
6.0 Titegroup, 1628 fps, tipping, .925”/3 groups.
6.5 Titegroup, 1667 fps, tipping, .942/3.
7.0 Titegroup, tipping less, 1932 fps, 1.133/3.
7.5 Titegroup, tipping, 1920 fps, 1.292/3.
8.0 Titegroup, 2006 fps, 1.458/3.
8.5 Titegroup, 2062 fps, 1.383/3.
Hornady .22 68 gr. HPBTM, Titegroup, M10 Savage, 22-250 16.5” bbl., rechambered Stevens 223 bbl., 9” twist bbl., 5-shot 100-yard groups.
5.5 Titegroup, 1248 fps, 1.467” avg./3 groups, 3 sideways.
6.0 Titegroup, 1343 fps, 1.283/3, tipping.
6.5 Titegroup, 1404 fps, .950/3, tipping.
7.0 Titegroup, 1524 fps, .757”/3, tipping.
7.5 Titegroup, 1627 fps, 1.167/3, tipping.
8.0 Titegroup, 1696 fps, 1.042/3, tipping.
8.5 Titegroup, 1764 fps, .800/3, tipping.
Hornady .22 68 gr. HPBTM, Titegroup, M10 Savage, Shilen 9” twist bbl., 5-shot 100-yard groups.
(Photograph attached)
5.5 Titegroup, 1340 fps, most sideways, groups of 1.4” and 1”; 4-shot group of 1.2”
6.0 Titegroup, 1433 fps, some going through sideways, groups of 1.4” and .6”, a 4 shot group of 1.9”.
6.5 Titegroup, 1517 fps, 1 of 15 sideways, others tipping, group-s of 1.0”, .9”, 1.4”
7.0 Titegroup, 1622 fps, tipping, groups of .6”, .9” and .8”.
7.5 Titegroup, 1713 fps, tipping, groups of 1.05”, 1.2” and .8”
8. 0 Titegoup, 1797 fps, no tipping, 6 groups avg. .838"
8.5 Titegroup, 1872 fps, no tipping, 6 groups avg. .958"