A friend's wife gave me a brand new set of RCBS forming dies when her husband passed away.  They are made to form .303 Brit into the Dutch or Rumanian Mannlicher & work as intended.

FWIW, the 6.5x53R was the preferred 800 to 1200 yard "match rifle" cartridge until it was ruled off the field by a requirement that the game could only be played with rifles chambered for the 7.62 NATO cartridge case.  With a proper barrel, the 6.5 cartridge will still play with the big boys.

The Mannlicher action, often converted to single shot, was preferred because the trigger was much easier to adjust to the minimum spec than was the Mauser.  Rules for the Match Rifle were the same as for Creedmoor; 10 lbs & 3 lb trigger pull.