Home Forums Reloading Big Game Rifles .243 90 grain Scirrocco II, E-Tip, Berger Hunting, 1:10T Stability???

Another aspect of the calculator as cited in "A New Rule for Estimating Rifling Twist An Aid to Choosing Bullets and Rifles," is the large role that temperature plays. Here in Southeast Alaska I have low temps (0deg at the lowest), Low barometric pressure, and high humidity (all working against me). It is interesting to play with the temperature on the stability calculator and see how quickly a bullet becomes unstable at lower temperature.

I don't know how accurate the modeled results are, but... I am surprised to say the least.

As with many things in life, length matters.

Only in this case, length is a negative...

FWIW, my oldest son waxed his first 2 deer at age 12 in Tx with an 1885 Low Wall 243, using my loads w/85 BTHP, first one dropped with a grapefruit sized hole in backbone area at 300 paces, his second around 250ish was hit in the shoulder, ran 3 legged about 40-60 steps and fell dead. I am not kidding when I say that shoulder looked like a 130 Ballistic tip 270 hit it!

The 85 has proven over a LONG time to be a sleeper in the killing dept. for 6mm bores. It may not penetrate quite like say a SSII, 95 BT, or a Barnes, but on broadside shots, it's QUITE lethal to put it mildly.

OH, last but not least, the last group that rifle shot before that hunt, was using a 6x36 scope. At 200 yds, the first 2 shots went into 1/2", the 3rd made the group about 1-1.25" or so. IMR4350 and Fed cases. Flat, accurate, deadly. 10 Twisted Browning.

Today with the 90 grain e-tips - 41.5 gr IMR 4831 set 0.1" of lands resulted in (3) 100 yd. 3-shot groups (I had loaded them before hearing to kiss the lands)

1st group 2"
2nd group - buddy's model 7 - 2"
3rd group - buddy shooting my gun - 0.4" - go figure?

On second note, the 85gr BTHP shot lights out in the two guns with Re15, Re19, and H4350.