with a Jolly nature, still outpacing Mega Manectric and Mega Lopunny with. A spread of 252 Atk / 44 Def / 212 Spe with a Jolly nature is recommended if running Drill Run so that Mega Beedrill can outspeed and KO Timid Choice Scarf Heatran with it. Full Speed investment can be run if opposing Mega Beedrill and Mega Sceptile are an issue, but the Defense EVs help so much in tanking priority hits that it isn't generally worth sacrificing them to tie with two relatively uncommon Pokemon. However, the difference in power is evident enough with an Adamant nature that it is a highly viable option for teams that can afford Mega Beedrill underspeeding Mega Lopunny and Mega Manectric. For instance, Adamant Mega Beedrill's Poison Jab is capable of OHKOing Mega Lopunny and Mega Charizard X/Y, while Jolly Poison Jab is always a 2HKO. With Adamant, a spread of 252 Atk / 56 Def / 200 Spe is recommended, as it allows Mega Beedrill to outrun Tornadus-T, and with that Choice Scarf Tyranitar and Adamant Mega Lopunny, while still having some Defense EVs to help tank the aforementioned priority hits.
You see, jolly nature with a spread of 252 Atk / 80 Def / 176 Spe allows him to outspeed mega manectric and mega lopunny apparently. 212 speed EVs with a jolly nature can outspeed timid scarfed heatran and OHKO it with drill run. While these boosts are really helpful, see what adamant does.
Adamant Mega Beedrill's Poison Jab is capable of OHKOing Mega Lopunny and Mega Charizard X/Y, while Jolly Poison Jab is always a 2HKO. The power difference is HUGE.
With Adamant, a spread of 252 Atk / 56 Def / 200 Spe is recommended, as it allows Mega Beedrill to outrun Tornadus-T, and with that Choice Scarf Tyranitar and Adamant Mega Lopunny, while still having some Defense EVs to help tank the aforementioned priority hits.
And with all that in mind, the final desicion is up to you. However I recommend adamant nature since he can still outspeed M-lopuuny and OHKO many threats unlike the jolly one.
