Yes, the Max base power of Rollout without any modifiers on the last turn is 480 and with Defense curl it gets to 960 which is the highest possible. And the most damage possible to inflict can be done with Rollout. It is technically possible to do over 4 trillion damage with it. But without Defense curl the strongest move is Stored-power with all stats boosted(Max boost of 860 Source)

*Via calculations if the Shuckle is at level 100 and it has a defense enhancing nature with 31 IVs and 252 EVs in Defense and the Ledyba has a Defense hindering nature, after using all those powerup moves, without using Screech at all, and the Ledbya would still have a defense of 5, with a critical hit Rollout on the 5th turn, it can deal up to 821,360,590,800. But by sending Ledyba's defense to 1, almost 0 landing a critical hit on a level 1 Ledyba with any nature since 6 or 5/4 is approximately 1 as fractions don't exist in stats, on the 5th turn of Rollout, it can lash out 4,106,802,954,000 damage. 4 trillion 106 billion 802 million 954 thousand damage or 4 trillion 1 hundred 6 billion 8 hundred 2 million 9 hundred 54 thousand damage to make it easier to read this way. Almost an infinite amount of damage. This can be calculated by taking 2 of 100 and then using the forumla 5/2 * 614 which is Shuckle's highest defense stat at a Relaxed, Lax, Bold, or Impish nature with 31 Ivs and 252 Evs in the stat, +614/2 which gives 50% of 614, 307 *2*960*480^2/50) since /1 is pointless +2) *1.5 for STAB *4*2 for critical hit. The problem is then worked out from there until all the stuff that needs to be added and multiplied is completed.*

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