2003 US Team. All International Palma/Fullbore is shot with 308. This Americanized "do whatever the hell you want stuff" isn't real Palma.
For the individual portion your allowed to run a hand load. So long as the cartridge chambers and doesn't leave marks on the bullet from the lands you are good. If it doesn't, you either sit it out or watch some Sasquatch armed with a reamer and a tap wrench go to work on your gun till it does. CIP rules are way different than SAAMI.
Back then it was "real" palma with a spec bullet; 155 Sierra Match King. What I mean by real is it was just ONE bullet. Later people started pissing and moaning and so the rules were changed. Now basically any 155 pill is legal.
-This really sucks in my opinion as the level playing field is gone and block coaches have to keep a Ouija Board within arms reach from one relay to the next because wind calls become ammo specific. (gay, it's a team event even if you are shooting the individual portion)
Most loads back then were hovering around 47-48 of Varget or VT N550 with a 210 Federal or the "Russian" primers that Mid Tompkins and Bob Jones were importing.
2003 was in Bisley. For the team events the supplied ammo was British made Radway Green. -Open core 155 grain machine gun pills. It sucked(s). Velocity on that stuff is a bit lower than the nuclear hand loads typically run. Host countries supply the ammo for the team event. Most of the time its shit and host countries are well known to lot pick so they shoot the cream...
On a 30" tube with a .300"/.3075" bore velocity was typically in the high 29's to low 30's. On that note. You DO NOT need a 298/3075 barrel to shoot palma. All you do is ramp pressure and encourage copper fouling. That's old school stuff from way back in the day when "Mexican Match" ammo was first tried. Mexican Match has nothing to do with Mexican made ammo. It was the Late 1960's and it was (I think, if I recall correctly) the Pan Am games were in Mexico. Mid Tompkins was shooting it. The ammo sucked. He pulled bullets, weighed out powder, and gassed them back up. Then they kicked everyone's ass. lol. The term has become a bit diluted since then, but that's how it started. Those bores were 298/3075. As what typically happens, the details get lost and folks suddenly fall into the "must be tighter tolerance" pit that consumes so much of the shooting community.
The Brits played with some 34" tubes in 2003. They were able to make them work. The increased sight radius helped along with a spike in velocity. The trick is you really have to be on your "A" game to run a barrel that long. Your shot sequence and follow through demands that you have your poop in a group. They did and kicked ass that year. Brits took the gold for the team event. Little Sheri Gallagher killed everyone in the individuals. Love that girl, known her since she was a pig tailed brat running around ranges with Mid and Nancy.
Hope this helps.
C.