From: Bart Bobbitt <bartb@hpfcmgw.fc.hp.com>
To: bdg@idaho.amdahl.com
Subject: Re: Springfield Scopes

About rangefinding and trajectory compesenting scopes. . .

For years, several scope makers have tried to devise means to get
first-round hits on targets.  Their problems have been:

    * matching the trajectory-compensating adjustments to the bullet's
      ballistics.

    * getting the target range accurately determined.

These are kind of a `catch 22' story.  The longer the range, the harder it is
to accurately measure it with triangular systems; the type most used with
sporting rangefinders.  Also, with longer ranges, the more a bullet drops
for a given horizontal distance traveled.

Here's some interesting information on rate of fall for the 7.62mm NATO
round.  At 1000 yards, the bullet drops about 0.8-in. for each yard of
horizontal travel.  That means in 10 yards, the bullet has dropped 8-inches.
Estimating ranges at 1000 yards accurately within 10 yards has been done for
sniper teams using a 1 metre baselength rangefinder.  Those little hand-held
rangefinders found in outdoor catalogues cannot deliver that kind of accuracy
reliably.  Plus, the atmospheric conditions changing from day to day makes
long-range first-shot hits a lot tougher.

But scope dealers and their marketing groups put together ads and campaigns
that really make lotsa folks think it's easy.  But even with the very best
in long-range highpower competition rifles at exact and known ranges, making
the first shot hit within 10-inches of the middle of the target is the
combined effort of a rifle that shoots less than 1 MOA at the distance fired
at, doping the wind correction exactly, and using the very best in handloaded
ammunition.  Trying to do that at an unknown range could be fun, but its
practicality might be questionable.

Lotsa folks try it, though, and if you do. . .best wishes.

Best regards,

Bart Bobbitt