All of those things are normal. I load my Glock magazines one round under capacity because it's easier to seat the magazine that way.
1. The magazine spring gets weaker while it's in use, so it's easier to load rounds into it.
2. The spring coming around the plastic muzzle cap on the guide rod is normal. I've had it happen with two G27 factory guide rods now, the spring won't come off, it just makes it a little bit of a pain to put the guide rod back into the slide.
3. The copper/brass on the feed ramp happens when the softer brass casing or copper bullet jacket rubs against the hard steel of the barrel as a round is chambered. You'll also see the same thing on the little rail on the bottom of the slide. What I find works best to clean it off is a phosphor bronze brush with Hoppe's #9 bore solvent. After using the phosphor bronze brush, I use a nylon brush because the bronze will embed itself in the steel as well but it's much softer and easier to remove than copper or brass. Then I dry the steel surface, wipe it with Ballistol oil for corrosion protection, then wipe dry.
1. The magazine spring gets weaker while it's in use, so it's easier to load rounds into it.
2. The spring coming around the plastic muzzle cap on the guide rod is normal. I've had it happen with two G27 factory guide rods now, the spring won't come off, it just makes it a little bit of a pain to put the guide rod back into the slide.
3. The copper/brass on the feed ramp happens when the softer brass casing or copper bullet jacket rubs against the hard steel of the barrel as a round is chambered. You'll also see the same thing on the little rail on the bottom of the slide. What I find works best to clean it off is a phosphor bronze brush with Hoppe's #9 bore solvent. After using the phosphor bronze brush, I use a nylon brush because the bronze will embed itself in the steel as well but it's much softer and easier to remove than copper or brass. Then I dry the steel surface, wipe it with Ballistol oil for corrosion protection, then wipe dry.