Answer: The FNAR is still legal in Maryland.
Rant: I live in Maryland. The new law is ridiculous. Most crimes in Maryland involve handguns, not rifles. The targeting of rifles is driven by hype and politics rather than statistics and logic.
Details:
In addition to the rifles explicitly named, you can no longer purchase a "copy cat" rifle.
If the rifle has 2 or more of these features it is considered a "copy cat".
--Folding stock
--Grenade or flare launcher
--Flash suppressor
A "copycat" also includes
--A semiautomatic centerfire rifle that has a fixed magazine with a capacity of more than 10 rounds
--A semiautomatic pistol with a fixed magazine that can accept more than 10 rounds
--A semiautomatic shotgun that has a folding stock
--A shotgun with a revolving cylinder
However many auto loading rifles avoid the "copy cat" status if you purchase without the magazine. You can legally buy the magazines in another state and bring them back to Maryland.
Rifles chambered in .308 are considered hunting rifles and exempt. The FNAR is still legal. But you must buy mags over the 10 round limit out of state.
Tube fed .22 rifles are exempt from the 10 round capacity limit.