What would cause a case to do this? 4 or 5 rounds have done it in two different guns.

First gun was a DPMS Ammo was Hornady 168gr ELD Match with 47.2gr of CFE 223 powder.
Second gun Ruger SFAR Ammo was Hornady 168gr ELD Match with 46gr of CFE 223 powder.

Reloads ? Looks like the bolt face is gouging the case but if it's in two different guns I would suspect the loads

So....we need more details.
Gun
Ammo
Action
Factory or hand loads
More pics of the brass

Primers flat,high pressure!

308 Winchester? Double check your powder charges and scale. Looks like some pretty serious over pressure issues going on, but the charge weights you have listed are in line for 308 Winchester with 168 grain bullets.

back the gas setting off on the SFAR

one click and try it

that is what over gassed looks like it rips the case out of the chamber before it has a chance to shrink back down in size

Are 308 loads in a gas gun suppose to be lower pressures than bolt guns?

I see what looks like burrs on the one case.
Really shouldn't be that with high pressure.
Should only be indents where the case was pushed into the bolt face.
Also, although the primers seem somewhat flattened, I see no cratering of the primer, which usually happens with pressure high enough to mark the case like that.

most gas guns yes
the issue isn't so much in the lock up strenght but the Gas port pressure

the M1 Garand is an excelent example of this it has about the longest possible distance to gas port you can get , it is also 2 way hole
the M1 doesn't have a way to blead off extra gas when the op rod had moved far enough to vent excess gas , so to much gas, too much gas pressure = bent op rod

this is why M1Garand safe 30-06 ammo is a thing slow burning powders that optimize long burn for greater velocity in a bolt action , mean your still too high of pressure for the gas port near the end of the barrel

on an M1 it needs to be a larger hole and honestly wasn't a hole at all on the early series pre-WWII in 36-39 they had what were known as Gas trap M1
an explanation of that

Yes Sir