The 30 M1 Carbine was always a "rough" made item and was not known
as a tack drive but a fire power weapon.

I worked on a lot of them as a gunny in the Navy and never did care much for them. At 250 yards a hit was one out of 50 if lucky.

H110 can use as much as 15.5 grains of powder...........
I load Herco at 10 grains and get a free load every third time I pull the trigger.

The Mag is the main problem with this weapon.
Sort of like a Auto pistol...... you need to mess with them to get them to work.
The iron sights are the second big problem.