Beedrill
Bug / Poison
***** Name Choice
Item Choice Band / Choice Scarf
Nature Adamant / Jolly
Moveset EVs 252 Atk / 4 Def / 252 Spe
~ U-turn / X-Scissor
~ Poison Jab
~ Brick Break
~ Aerial Ace / Pursuit
Similar to its bug buddies, Beedrill's stats are fairly mediocre. Beedrill's STABs are average and its movepool is at least better than some of the other Bug-types. U-turn is a great scouting move that also damages your foe in the process. X-Scissor has more power than U-turn and Beedrill isn't forced to switch after use. Poison Jab is STAB to back up when Flying-types show up. Poison Jab also replaces the now special Sludge Bomb. Brick Break will hurt Steel-types as well as Rock-types harder than most of Beedrill's moves. The final move comes down to whether you hate other Bug-types, or you think other Pokemon would attempt to escape Beedrill. Pursuit is useful against frail Psychic-types that might switch out in fear of X-Scissor or U-turn. It also is Beedrill's best attack against Ghost-types such as Drifblim and Rotom. Aerial Ace is useful for other Bug / Poison-types.
***** Name Swords Dance
Item Life Orb
Nature Jolly
Moveset EVs 252 Atk / 4 Def / 252 Spe
~ Swords Dance
~ X-Scissor
~ Poison Jab
~ Brick Break / Aerial Ace / Pursuit
In this set, Beedrill attempts to raise its mediocre Attack from 259 to 518. With a Life Orb this figure becomes 673. The problem with this set is Stealth Rock can ruin Focus Sash, which is why it isn't present here. With something as frail as Beedrill, it might as well attempt to hit as many Pokemon as it can. Brick Break is Beedrill's best weapon against Rock and Steel-types, Aerial Ace demolishes Bug / Poison-types, and Pursuit is its best weapon against Ghost-types.
***** Name Agility
Item Life Orb
Nature Adamant
Moveset EVs 252 Atk / 4 Def / 252 Spe
~ Agility
~ X-Scissor
~ Poison Jab
~ Brick Break / Aerial Ace / Pursuit
This set uses a different approach for Beedrill than the Swords Dancer. Instead of raising Beedrill's Attack stat, it attempts to boost its Speed. After an Agility, Beedrill reaches a respectable stat of 498; outpacing even the likes of Electrode. The same attacks apply to this set as well. X-Scissor is Beedrill's reliable STAB move followed by STAB Poison Jab to at least damage Flying-types. Brick Break, as mentioned, will demolish Rock and Steel-types. Aerial Ace dominates against Bug / Poison-types. Pursuit hurts Ghost-types.
***** Name SwarmSalac
Item Salac Berry
Nature Jolly
Moveset EVs 252 Atk / 4 Def / 252 Spe
~ Substitute
~ Swords Dance
~ X-Scissor
~ Pursuit / Brick Break
This is a different approach to Beedrill than his usual sets. Stealth Rock is a major pain for Beedrill, but this set can still use it to Beedrill's advantage. After switching into Stealth Rock, Beedrill should be left with 75%. Substitute down while the opponent switches or attempts to cripple Beedrill. After that attempt to Swords Dance or repeat the Substitute. After that, Salac Berry should activate and attempt to finish the job. Pursuit is probably the best move in slot four, but Brick Break still works well next to X-Scissor. Keep in mind that you're walled by Bug / Flying-types with X-Scissor and Brick Break.
Endeavor isn't a horrible choice on this set in slot four. If you plan to use Endeavor, it is best to make your HP even instead of odd. This way, you will set up Substitute 5 times (or 4 if Beedrill has stepped into Stealth Rock) and activate the Salac Berry and leave Beedrill with 1 HP.
Name Insect Endeavor Item
Item Salac Berry / Focus Sash
Nature Jolly
Moveset EVs 4 HP / 252 Atk / 252 Speed
~ Substitute / Endure / Swords Dance
~ Endeavor
~ X-Scissor
~ Swords Dance / Pursuit / Brick Break
Novelty at best, but still can work. You can use Substitute, Endure, or Focus Sash to help you get down to 1 HP. Substitute can give you a chance to use Swords Dance and isn't completely tarnished by Stealth Rock, which is the reason why its listed. The advantage is Beedrill's HP isn't very good, thus giving an excuse to use Endeavor even when you don't have 1 HP. X-Scissor should be used as it's his better finishing move than Poison Jab, as Steel-types are immune to Poison anyway. Brick Break gives an excuse to hit Steel-types who would otherwise block X-Scissor. Pursuit is another consideration to hit more Pokemon neutral.
Focus Sash is best alongside Swords Dance in slot one and Pursuit or Brick Break in slot 4. Make sure Stealth Rock is out of the way before you attempt this with Focus Sash.