PPU and S&B makes a 173gr round that closely emulates the military round, in spitzer design. Military surplus is often found, but not so much in bulk anymore.
The 139grain stuff is sometimes not very accurate in the worn military bores with the military twist, also, the longer bullet give more surface area for worn rifling to grip. And another downfall of the lighter bullet is the military cut chamber. Most chambers have a lead cut to clear the longer round-nosed or the more modern heavy spitzer bullet, which means the light weight shorter 140gr. spitzer has to travel a ways before it reaches the rifling, thats another situation that can affect accuracy.