Tom,
Your local gun shows are a good source of M1 rifle ammo components.
The easily available/cheap pulled 147 grain M80 bullets are NOT exactly like the 150 grain M2 .30 caliber bullets, but they are close enough to shoot and work just fine for M1 rifles.
The M80 specification bullets use guilding-clad mild steel jackets compared to the guilding metal lead core M2 bullets. They are also boat tailed and have a sharper ogive than the M2.
However, I've loaded and fired several thousands of them in the last few years, and they shoot just fine in several M1 and M1A rifles. Beyond 300 yards, they shoot a little bit flatter than the M2 bullet, but still close to GI ammo.
Surplus powder from Israeli 7.62x51mm machine gun ammo will also load and shoot just fine in the M1.
HTH
John
HTH
John