ON the SigPro 2340 magazines...
I don't know when your magazines were made, but for my SigPro the plastic composit finger stop slides off the magazine for cleaning by depressing a pin... then everything dissasembles. Very solid design.
I've shot over a 1000 rounds through mine with not one malfunction of factory ammo, or my own ww cast bullet reloads.
It eats them up, and never, never has jammmed.
This is one of the finest Sigs ever made period, and needs know refinement. But, as with any make of firearm, there will be some that have problems.