From: toby@stein.u.washington.edu (Toby Bradshaw)
Subject: Benchrest rifles -- how low can you go?
Organization: University of Washington, Seattle

I just bought some 68gr FB bullets from Allie Euber for the upcoming
benchrest summer season, and thought some of you might be interested in
the test results.  I normally shoot in our local open class, which consists
of 2 10-shot matches at 300 yards (at 300 yards it's usually possible
to count the bullet holes so that no moving backers are required).
Because of a highpower match on the 300 yard range, I had to test the
bullets at 100 yards on the public range.  I'd never fired my benchrest
rifle for group at 100 yards, just some fireforming.

Rifle is a cruiser weight (~18 pounds) unlimited 6PPC, Wichita action,
Hart 1.250 untapered barrel, Jewell trigger, McMillan stock, smithed
by Seely Masker.  Scope is 36X Leupold.  Brass is SAKO USA, standard
BR prep.  Primers are Fed 205M.  Powder is Australian H322.  Rounds
assembled in Wilson hand dies, bullets seated to touch lands.

Normally, lighter loads will show some vertical dispersion, followed
by no vertical at optimum loads, followed by random scattering of
shots at primer-blowing pressures.  Load development starts with
3 shots of each load (groups never get _better_ with 5 shots, so
why shoot 5 unless the three look good?), then another 2 rounds are
loaded and fired when groups begin to tighten up.  Of course, the
loads that work well at 100 yards can suck at 300, but I got some
indication of where to start for my regular matches.

Powder charge (gr)	# shots		group size (in.)
26.8			3		0.209 (1.5 bullets vertical)
27.0			3		0.241 (1 bullet vertical)
27.2			3		0.208 (1 bullet vertical)
27.5			5		0.028
27.8			5		0.191 (round group)
back to 27.5		5		0.128 (round group)


I think this test illustrates something not appreciated by most folks
shooting factory equipment.  The load, while somewhat important, is not
critical for excellent groups.  If the rifle is well-made, and the
components properly assembled, a grain of powder doesn't mean much at 100
yards, except for competition.  All 24 shots, with all loads superimposed
on the same target, would hide under a dime with room to spare.  The small
group, in the zeroes, has 5 shots in a hole that a .308 bullet will not
fit through.  If you like accurate rifles, let me suggest that you give
benchrest a try. It never ceases to amaze me that human hands can
fabricate a machine capable of such accuracy, and are able to create such
a rifle on demand.  The cost of a benchrest rifle over a factory rifle is
significant, but the accuracy differential is even more significant.  One
need not compete to appreciate the ultimate in rifle accuracy shooting.

-Toby Bradshaw
toby@u.washington.edu