There is American made 7.62x54R ammunition available,
When I first bought my Mosin I couldn't find any brass, and I refuse to shoot that cheap surplus stuff in any of my guns.
I found some Winchester loaded stuff for $18 a box. I bought 10 boxes, shot and reloaded it. I don't reload hot, plus for offhand shooting (which is my weak point and where I need most of my practice) I load mild cast bullet loads. I still have most of that brass.
I shoot my surplus rifles in and practicing for CMP Vintage Rifle games.
I bet over the life of my gun (or my ownership of it) and the original cost of the loaded rounds, I have shot it cheaper then it would have cost me to shoot surplus ammo.
Another plus for reloaded ammo, is I don't have any steel bullets. Our club banned steel bullets on our range during the summer when we have fire bans. It does spark, and does create a fire hazard.
But to each his own. They present ammo drought hasn't affected my Mosin shooting one bit. Plus I create better, more accurate ammo.