Edward, all the Palma chamber's I've shot, including the ones used on International teams, have had the leade set back a bit shorter than SAAMI spec. That's so the 155's would seat gently into the lands centering them well. And 30" barrels in Palma rifles shoot 155's out about 3000 fps with the same pressure (about 52,000 cup) as the same load shoots them 2800 fps from a 24" barrel. That was proved in 1991 when the 155's were first used in competition; short barreled rifles had subsonic problems with that issued ammo at 1000 yards.
Are you aware of the accuracy disaster Lake City's M118 with ball powder caused? That aside, if one gets best accuracy with ball powder, do it.
I wrote the first rule for Palma rifles that was put in the NRA High Power Rule Book back in the 1990's. It stated any rifle chambered for the .308 Win. or .30-06 could be used. That was to allow folks whose only match rifle was a .30-06. The reason it was changed later was twofold and had nothing to do with the ranges used. The rest of the world used the .308 Win. in their fullbore matches and the .308 was typically more accurate, so the US Palma Team wanted folks to learn how to dope wind for the .308 as well as shoot it well enough to make the US Palma Team and be competitive with other countries.
Note it was the use of the .308 in NRA matches starting in 1963 that 3 years later, the short and mid range target's scoring rings were reduced 'cause there were too many unbreakable ties shot with .308's. A few years later, the long range target's scoring rings were made smaller for the same reason.
US Navy Distinguished Marksman Badge 153
Former USA Palma Team Member
NRA High Power Long Range High Master
NRA Smallbore Prone Master
Last edited by Bart B.; December 30, 2012 at 08:29 AM.