... it seems to have messed up (bent the lips I assume) at least two magazines on two separate guns...
I can't think of a single instance in which this statement would hold true.
I took two pistols with good mags to ECR. Each had been shot more than 300x minimum, probably more. Each had never malfunctioned in the slightest. I used Tula for the very first time in both, and had my first failure to lock back on empty on both guns that day. I thought the ammo may have just been light on powder or whatever, but no. Those magazines still have intermittent problems with locking open with any ammo, but not my other magazines. Draw your own conclusions as to why, but that is what happened. I don't understand it myself. I can't see any problems with the magazines.
Sometimes the problem is the weapon. Most of the time people will blame steel cased ammo because it makes them feel better than saying they have neglected to properly maintain their own firearm.
It isn't that Tula or any steel cased ammo is bad for you entire gun but, it is very hard on the extractors. I use it but sparingly and I always examine my gun after using it.
Also, with steel cased ammo, be careful you're not shooting corrosive ammo through your gun. This will destroy your barrel.
If steel case ammo does not run in your gun....your gun is crap!