In early 1991, I helped the US Palma Team (as a former member) test
Sierra's prototype 155-gr. Palma bullet for a load to use for the 1992
International Palma Matches. One of our objectives was to use only
metered powder charges as the ammo would be loaded on a Dillon
progressive. Sever or eight of us ended up getting best accuracy with
about 45 grains of IMR4895.
Winchester had been tasked with making the cases. We wanted them to
use the same case forming dies (which are still boxed in storage at
the plant in East Alton, IL) used to make the famous WCC58 cases that
were (and still are) the most uniform .308 Win. cases ever made. But
they were too thin for Winchester's liability and legal issues, so a
thicker case was made. It took their production line four tries to
get the cases uniform enough in body and neck wall thickness for the
Palma Team's standards.
The guy whose businesses' loading room was to be used to make the ammo
had both his sons (and daughter too, I think) hand-chamfering some
300,000 case necks so bullets wouldn't have jacket material scraped
off when they were seated. Then the first of two Dillon 1050
progressive machines was set up to prime and uniform the necks of the
cases. Priming was easy to do using Federal 210M primers. A Lyman
die with neck expander was used to uniformly size the case necks to
give a medium tension on the .3084-in. diameter bullets.
A second Dillon 1050 progressive was set up to charge the primed cases
and seat bullets. An indicator was used to tell if the metered powder
charge was correct (visually, as well as one could see).
These two machines made all the ammo that was used in the 1991 Rocky
Mountain Palma Matches International Division and the 1992
International Palma Matches; both shot at the NRA Whittington Center
in Raton, NM. A single lot of powder was used, but several lots of
Federal primers were used. Each time a new lot of primers were used,
the ammo lot number would change. And some ammo lots shot better than
others; no doubt the primers' variance caused that. One box of twenty
rounds and a couple of sighters were taken to a local test range where
the business owner's Palma rifle was clamped in a machine rest to test
the ammo. That Model 70 with a 30-inch long, whippy barrel put 20
shots into 2.7 inches at 600 yards. That's benchrest quality.
All of which means progressive loaders can make accurate ammo. It's
which one and how it's set up and used that makes the difference.
