THE HANDLOADING BENCH
308 Winchester Rides Again By Laurie Holland
Downsides?
That may be the rub! The new 230 Berger Hybrid is a very long design and if you throat your chamber to suit, there will be precious few other bullets you can use in that rifle. Recoil and torque increase too - an issue for the F/TR competitor on a bi-pod, even more so for the prone shooter resting on his elbows. Conversely, barrel-life will decrease substantially – I
The Hybrids’ meplats offer scope for further improving the BC a little through ‘tipping’ or pointing
from Bryan Litz’s book Applied Ballistics for Long Range Shooting 2nd edition except for the 215 and 230gn Hybrids from Berger Bullets’ Quick Reference Sheet and marked so: * . This pair looks to be quoted too short in relation to the other bullets.
‘Ideal COAL’ and Comp. COAL refer to measured cartridge lengths with a bullet seated so the shank to boat-tail junction coincides with the neck/shoulder junction on the case. COAL is the resulting overall length of the cartridge, ‘Comp COAL’ is as measured from the case-head to the ogive using callipers and a Hornady bullet comparator body / .30 cal insert.
reckon 2,000 rounds, maybe 2,500 if you’re lucky. That’s partly because heavy bullets produce faster throat erosion, other things being equal. (Heavy = high inertia = increased period that the throat is subjected to peak pressures and temperatures with each shot.)
Moreover, we’ll use a compressed charge of the densest, highest-energy powder we can find whose burning rate also suits the cartridge-capacity and bullet-weight combination to obtain maximum velocity from this capacity-constrained case. That is double-base, hot-burning Viht N550, Alliant Reloder 17/Elcho 17, or Hodgdon H414/Winchester 760.
Notes BSL = Bearing Surface Length (Shank length). Data
Some people may wish to chamber their barrels with longer freebore so the bullet sits higher in the case- neck to maximise capacity. The purpose of the ‘Comp COAL’ value is to give a feel for how the different bullets stack up on the required amount of freebore. Bullet seating positions were obtained in a fairly crude manner using a second bullet held alongside the case exterior for comparison, so these values should be treated as a rough guide only.
Optimal twist rates are as supplied by Berger Bullets and will provide full stability in all normal meteorological conditions down to dry freezing air at sea level and at standard velocities. A slightly slower twist will often work in ideal conditions (high temperatures and humidity at altitudes above sea level).
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