Is it cheating or bad design?

Spelling mistake:  Developers of this game don't know how guns work, or are people just cheating and EA can't do anything about it?

Cheaters. you can report them alll the time. Keep in mind if you play battleroyale mode the developers bowed to the cheaters so you cannot report them but you can make a video record.You should know the difference between aimbot and triggerbot both are cheats. This is the report page but again might be closed or moved.  

https://help.ea.com/en/help-tools/report-a-player/

When there is no spectate or kill cam and no ping limits, it's hard to know.

The thing about ping is that if everyone has a low ping, good. If everyone has a high ping, good. But if there is a big spread between someone with a 12 ms ping and someone with a 262 ms ping, there is a 1/4 second smear of time occuring on the server where it tries to guess which person should be credited for hits and misses. It affects everyone, not just an interaction between the lowest pinger against the highest pinger, but everyone in the server experiences weird decisions about what is considered the current realtime. Throw in packet loss and server and client lag spikes and variably high CPU usage, and all sorts of weird things happen. That's why you die around corners or get insta-killed against legit players.  If EA cared, step one would be a ping limit.

Noticed it since season 2 dropped, slow rof sidearms outgunning assault rifles & lmg's ect, pretty sure something is going on, see more & more players since season 2 running with sidearms & 1 hit killing.

If you are a controller users, all I can say is tough **bleep**! It is by weapon damage and hit location. FYI, mouth and neck are NOT headshots in this game. You have to hit upper head, so in the face may have 2 different damage values. You should know the .44 is a 2 shot kill just about anywhere on the body at close range.

If you are on PC dying to controllers like this, know that they have the advantage in every way. 

Netcode is their advantage.
Aim Assist is their advantage.
25% less recoil and 25% less bloom is their advantage.
Because of these, they can take weapon mods that cost less and get the ones that balance out the gun for them, while we try to control recoil mostly, which is... their advantage.

If it is PC on PC, netcode and ping matter (Higher wins).

EA IS A TRASH COMPANY! NEVER BUY THEIR PRODUCTS AGAIN!

They do not listen, they believe in controller superiority, they are greedy AF and don't respond to legit questions.

Sounds like more a design issue. What gun are you using?
More than half the guns are garbage imo. I've gotten most of my guns to 50 or at least 40 (with the exception of pistols).

Thought it was just me. BR was full of people with laser beam guns, I quit playing it at all because I was tired of being picked off by a full auto gun at 100 meters.  

It's hard to say for definite without video, but I'd be inclined to lean towards it being something like desync or packet loss etc rather than cheating. Next time it happens, it might be worth checking the damage breakdown information, as it might be that shots are being bundled. 

Usually netcode, probably only one of your bullet packets reached the server.  His 44 to face is a 1-shot. You need to take note of the damage in your death cam, then you'll see just how little damage he took.