To the original question and with unlimited logistics:
#1 M-1 Garand in the tanker configuration as envisioned by G S Patton only in 7.62 NATO.
#2 Standared Garand rechambered in 7.62 NATO.
These to me are the ultimate MBR for INFANTRY, tough as nails and accurate to 600 yards with iron sights.
A side arm would be the 1911A1 in .45ACP.
No logistics to speak of would have me armed with the most common weapons of the enemy.
