What caused inboard front disc brake pad to score the rotor?

Newbie take-aways from installing new pads in big Chrysler single-piston front calipers:

Rockauto is quite a bit cheaper than O'Reilly or Autozone, even after shipping, and the parts arrived in one or two days, thereby saving a trip across town to the parts store.

You need to bend the tabs on the outboard pads so they fit on the caliper nice and tight; tight enough that you've got to use a C-clamp to get it on. You'll probably have to hit the tab with a hammer to bend it.

Put just the slightest bit of high-temperature brake lube on the ways, where the tabs on the pads move.

Renew the anti-rattle hardware. I thought my old hardware was OK until I compared it to new hardware. My old stuff was all bent up, and I didn't realize it.

You're going to have to buy a pad-spreader tool to make the piston retract enough to get the new pads over the caliper. Those tools are not cheap! Why do they charge so much? Because they CAN! (I know you can move the piston in with a C-clamp, but that is too redneck for me!)

Install those rubber band O-rings on the adapter ways! They come in the brake hardware kit. I really like what they do for firming up the caliper movement.

After you install the new pads, hit the brake pedal several times before you drive away! You gotta get those pistons back out there where they belong before you're going to get any pedal.