Yes, APK is completely legal. It is the native file format that developers use to package an Android app; even Google uses it.

Downloading a modded APK is not a crime, but you're probably putting your phone at risk. Some apps are malwares, others steal money by making your phone pay for premium apps. So just be careful, don't install apps that do not have an icon.

The Modern Warfare 2 best M4 loadout is one of the best guns you can get your hands on, especially if you're just starting out. The stock version of the M4 is an incredibly well-rounded weapon, but it can be transformed into the best AR of the bunch if you utilise the correct set of attachments.

Throughout Modern Warfare 2's lifespan the M4 has established itself as a top-tier assault rifle. It is well-rounded with a fast fire rate, great TTK, and easy-to-control recoil. It truly is the weapon you pick when you want a primary that covers just about every scenario.