I started "Mexican matching" 54r ammo right after I purchased my M44,I had plenty of Bulgarian brass case surplus ammo and a friend gave me about 300 Speer .311 150 gr. SP bullets as a trade for some computer work I did.
Factory Win. SP ammo was $1 per rd. and boxer primed brass was scarce at the time,sense I already had my reoading dies and 30 years of reloading experience it wasn't a problem doing the conversion. As Mr. Gibson mention accuracy was greatly improved over anything the surplus offered. My rifles bores slugged at .312 and the .311 dia. Speer SP bullets were a much better match than the .310.5" surplus bullets.
After I worked up a nice accurate shooting load I converted about 150 rds. so I'm set for a long time.
Primer from surplus ammo.
Primer from my Mexican match ammo.