Well some of the newest Glock magazines may swell when loaded, and they may even swell enough that they won't drop free even when they're unloaded.
As to why the magazine release(magazine catch) feels harder to push, I don't know what would cause that. Perhaps there's residue built up around the magazine catch in the frame, or maybe there's a foreign object between the magazine catch spring and the frame.
Here's a video showing how to remove it. I'd use a curved dental pick as it's least likely to scratch the frame, you're almost guaranteed to scratch the frame with a screwdriver. To remove the spring, you use a pair of needlenose pliers to pull the spring out of the hole in the frame then push it back in. (removing all of those other parts is not necessary, I guess he just does it to get them out of the way)
[ame]http://www.youtube.com/watch?v=oE_AM6GWVsQ[/ame]
As to why the magazine release(magazine catch) feels harder to push, I don't know what would cause that. Perhaps there's residue built up around the magazine catch in the frame, or maybe there's a foreign object between the magazine catch spring and the frame.
Here's a video showing how to remove it. I'd use a curved dental pick as it's least likely to scratch the frame, you're almost guaranteed to scratch the frame with a screwdriver. To remove the spring, you use a pair of needlenose pliers to pull the spring out of the hole in the frame then push it back in. (removing all of those other parts is not necessary, I guess he just does it to get them out of the way)
[ame]http://www.youtube.com/watch?v=oE_AM6GWVsQ[/ame]