Riflechair is quite right: that phosphate finish on the late ones is a d*mned nuisance at the best of times. And, as pointed out, a bit of polishing will take care of it. Myself, I always try to keep a small stock of the early chargers on hand: nice and smooth.
It also makes big difference HOW you shove them down into the mag. Putting your thumb RIGHT at the back end of the rounds, right where they peek up out of the charger, generally will get them into the mag with a single, fast sweep. Putting your thumb halfway up the cartridge is just asking for a jam.
Some time, load yourself up 15 drill rounds, load them into chargers and load your magazine very slowly, just so you can watch what happens. You almost won't believe what the cartridges actually DO while they are being loaded. Do it right and they sort themselves out very nicely.
For charger loading practice, you really should have 10 or 15 drill rounds. If you can't find originals, you can load them up out of some of that Berdan brass we all have lying around. Just drill out the primers so you can tell that they aren't live rounds and then practise, practise, practise. Practice makes perfect.
Nice thing about chargers is that you can load rounds at an awful clip if you have practised. The way we were taught, you loaded 5 into the mag with a single charger, removed the charger from the guides, replaced it with another full charger, swept those rounds into the mag and then just slapped the bolt forward hard and fast. You didn't even remove the second charger from the guides: it removed itself, right quick.
MUCH faster than mucking about, trying to change magazines!
Have fun!