"Karl Townsend" wrote in
anews.com:

snip
We also shot the DPMS-308 off hand. I am just plain TERRBILE with this
heavy gun off hand. Any tips on learning to shoot a heavy rifle? I
could tell I quickly tired and couldn't make nice little tight aim
circles to shoot on the down stroke (my mini 14 method) We stopped
after two boxes of ammo, its a buck a shot.

If you are shooting offhand at stationary targets, the secret is to use
your bones to hold up the rifle, not your muscles. A heavy rifle is very
stable and helps to soak up recoil as long as you can hold it up OK.

I'm sure there are web sites with good pictures, but the idea is to park
the elbow of your support arm on your hip bone, and then park the rifle on
your hand somewhere near the trigger guard. Every rifle & every shooter is
a little different. I like shooting my 308 bolt gun up on my finger tips,
with my thumb on the bottom of the trigger guard. Lots of folks park the
rifle on top of a closed fist. The DPMS 308 is perfect, because you can
use the bottom of the magazine as a palm rest. You'll want a leather glove
to avoid the sharp corners digging into your palm. Ideally, you want to
rest the bottom of the magazine on the heel of your hand. In order to get
the right elevation and balance the rifle, you may have to lean back a bit.

I rummaged through some photos of my team shooting in last spring's offhand
league. Here is a photo that shows the general idea. He's shooting a
custom .223 "spacegun" built up on an AR-15 platform.

http://users.rcn.com/gwhite/Misc/Offhand_sm.JPG

Doug White