Is armor even worth it?

I'm fairly new to this game (been playing about 2 weeks or so now). Mostly been playing normal valley and farm with my friends, figuring out the game mechanics, spawns, where to find loot, running missions, etc. So I'm genuinely trying to understand this better, so genuine advice or answers would be appreciated.

I've gone into lockdown a few times (did TV station twice, and valley a few times), and every time I did, I got killed by a player running M61 ammo (I've even had people kill me with M61 in normal a couple times). Granted, this was pre-patch, but from what I've seen from the sub reddit so far is that M61 still one-shots to the head through any helmet.

I say this to ask, is armor even really worth running? From all the discourse I've seen on this sub, it makes it seem like my experience of dying to M61 is the norm, where most people run it. I guess I'm not really understanding the point of even running high-tier armor/helmets in lockdown/forbidden if M61 is the norm. Or is running into players using M61 more rare than this sub makes it seem and I just got unlucky with my lockdown runs?