In Battlefield 4, the progression system for unlocking new weapons, attachments, and gadgets is intricately tied to player performance and class-specific gameplay. The primary way to unlock these items is through consistent gameplay — accumulating kills, assists, and other points associated with your weapons and gadgets.

Unlocking Weapons
Weapons in Battlefield 4 are unlocked as players progress through class levels or by earning kills and other points (including assists and suppression) with specific weapons. Each class has its unique set of weapons, and the more you use them, the faster you can unlock new ones.

Unlocking Attachments
Attachments serve to enhance the capabilities of your weapons and are unlocked through two main avenues:
1. Gun-Specific Progression: Achieving kills with a particular weapon unlocks attachments for that weapon every 10 kills until all standard attachments are obtained.
2. Battlepacks: Additional attachments can be acquired through Battlepacks, which are rewarded randomly and can contain alternative attachments. After obtaining all standard ones, players can unlock these alternative attachments after every 50 kills.

Unlocking Gadgets
Gadgets are also tied to class progression and are unlocked by:
– Accumulating points through the use of gadgets in gameplay.
– Completing specific assignments or challenges related to a class. For instance, a player might need to earn a number of kills while using a particular gadget or fulfill certain objectives.

Special Assignments and Ribbons
Some weapons and gadgets may require players to complete particular assignments or tasks (e.g., sniper rifles may require a certain number of long-distance headshot kills to rank up faster). Additionally, players can earn ribbons by completing objectives that contribute to unlocking weapons and gadgets more efficiently.

Shortcut Bundles
While players can purchase shortcut bundles like the “Ultimate Unlock Kit,” it’s important to remember these kits primarily provide immediate access to base-game weapons and gadgets. They do not unlock attachments, assignments, or content from expansion packs, meaning players will still need to engage in gameplay to fully access the available arsenal.

Summary
The core of unlocking new weapons, attachments, and gadgets in Battlefield 4 centers around actively participating in matches and utilizing your arsenal effectively. The satisfaction of progressing through your weapons and classes not only enhances your gameplay experience but also gives you deeper engagement with the game’s mechanics. For players who want to expedite the process, shortcut bundles can provide a temporary advantage for base game items but are limited in the full range of unlockable content.