I know I owned and shot one for a couple of years before selling it.
I know ammo is hard to find (that weapon started me into reloading) and the round is anemic compared to 5.56, certainly compared to other .30 calibers.
I know the 15-round magazine is half what an M4 can provide.
I know enough.
I had no trouble finding it. A long time ago I bought some old Dynabit-Noble stuff, all worked fine, and more recently 500 rounds in bulk.
Of course today, you might have to wait a few months, and then it will probably be banned.
Most have been upgraded to be able to take the later 30 round magazines. Mine did not have the proper mag catch for that, until I put one in, a very simple process, with a part donated by my M1 Carbine collecting co-worker.
He had one legal M2 Carbine as well. Only full auto weapon I've ever fired. Hard to control a newbie like me.