I didn't have any trouble with the standard velocity Underwood cycling in my gun. I did have problems with the Lehigh branded version that I bought as loaded rounds from Wilson Combat. The Lehigh branded version was only starting out with a muzzle velocity of 1075 fps, which is rather low for such a light bullet. It apparently did not generate enough slide velocity to fully cycle the gun every time. The Underwood ammo starts out 200 fps faster and cycles the gun fine. I also tried some XD handloads using load data off Lehigh Defense's (not Wilson Combat's) website, which launched at an average velocity of 1160 fps (much faster than Lehigh's factory ammo, go figure) and it functioned fine.
With respect to the first part of your post, see sgt127's post. It's not just external barriers that we have to worry about. Also, it is never a good idea to predict the exact type of trouble that will find you at any point in time.