Q: I’ve been told that the .338 Win Mag is too slow to keep up with long-range .30-calibre projectiles. But the 180gn Nosler can be driven at over 3200fps (975m/s) and the Barnes manual lists the 185gn MRX BT doing over 3000fps (914m/s) and 210 grainers at 2900fps (884m/s).
Surely these velocities place the .338 alongside the .300 Win Mag and .300 Weatherby? What’s your take on this? Am I right or am I wrong?
Jeff Castle
A: You are partly right when you say that very light .338 bullets can be pushed along quite fast — actually, as fast or faster than similar bullet weights from the .30 magnums.
This is because light .338 bullets have less bearing surface than the 180gn and 200gn in .30-calibre, which means less friction, and pressure allows them to be driven at fairly high velocity. The larger frontal area of the .338 also offers an advantage.
The problem with really light .338 bullets is ballistic. Heavy .338 bullets have the high sectional density (SD) and ballistic coefficient (BC) necessary for the good aerodynamics that you get from long, heavy-for-calibre .308 bullets.
Sectional density is critical to gaining deep penetration, particularly when hunting the size of game the .338 was designed for — bear, moose and wapiti.
The lightest .338 bullet with stout construction is the 210gn Barnes with SD of .263 and a higher BC than the 225gn TSX FB — .404 against .386 — and it can be driven at 2900fps (884m/s) against 2700fps (823m/s) for the 225gn.
I am a big fan of the .338 Win Mag but my rifle is long-throated and drives the Barnes 225gn TSX FB at 2980fps (908m/s) ahead of 77gn of AR2209. Sighted-in for a 250yd zero it is 2½” high at 100 and drops 16” at 400, where it retains 2285ft-lb of energy.
I’ve never tried the 210gn Barnes, but it should be as good.
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