Shotgun spread seems like it could stand to be tweaked. Damage seems very random. It's not uncommon to miss all pellets at very close range, especially with sawn off shotguns but also with regular.

The situation seems to usually be you either outright kill your target, or do very minimal damage. Seems a bit too random, and a slightly tighter spread may be the answer.

Pellets also seem to have strange travel time. Not uncommon to shoot and see them impact a wall at a significant delay, for even short distances traveled.

Used the sawed off against a zombie from almost point blank range and did not hit/kill him. So either the weapon does not damage sometimes or the weapon spread is so bad that it missed even over short distances.

Right now at least the sawed off version apparently only shoots a single projectile that is not very accurate.

They're only firing a single pellet for some reason.

I shot a player that asked to be killed today because he wanted a respawn. I used the pristine IZH 43 (not sawed off) and I needed 6 rounds to finally kill him. I aimed for the head at less than e meter away. All I could see is that his shirt was ruined after the first shot, but he didn't get down.
The guy was utterly surprised that I couldn't take him out. ;)
After the sixth round he died.
I think I used hipfire, but with RMB pressed.

I can confirm that on stable the shotgun is currently only shooting one pellet, at least some of the time.

Most of the people aim wrong with the shotgun. Right the end of the barrels are the aiming point (Corssair). You have to point with the barrels directly to the head (half of the head under the both barrels) to hit the head. If you don't do that you will not hit anything on short distance. The pallets don't spread this much if you didn't saw it up. Try it an place a comment here.

I definitely know how to aim with it, I've used it a lot. I'll do more extensive testing next time I grab one, but I am near certain it was shooting a single pellet.

The shotgun is basically the gun I've used for probably 75% of my time playing DayZ, both SA and the mod.

edit
sorry not the best test ever but here's a video
https://www.youtube.com/watch?v=BV_iFYlJFWo&feature=youtu.be

We have tested this issue and got completely different results. One shot can be more or less absorbed by a vest a player is wearing. That is completely plausible. In 40% of cases a player dies from the next shot (almost 90% if shot from point blank range). A third shot is always a killing blow.

The shotgun's damage is not off by any means.

There is a problem with only one pellet being rendered with each shot, that is a different problem however and it is not the point of this issue, therefore I am closing this particular issue.