Not to be rude, but your set is mediocre at best. Also, Fissure is a very, very unreliable move that should almost never be trusted in competitive.
You seem to be going for an offensive Primal Groudon, a damage dealer. This could also be interpreted as a semi-stally burn spreader.
Either way, your set could be optimized. I'll go over each possibility for Primal Groudon.
Your Nature pretty much determines which set you will want to use, so pay attention to that category.
If you want a Physical heavy damage dealer, then I would go for this set:
Groudon @ Red Orb
Nature: Preferably Adamant Nature, but several others would work (such as Brave, other attack increasing natures, purely defense impacting natures, Jolly, natures with no impact on stats).
IVs: Best you can get
EVs (If any Nature listed above other than Jolly): 252 Attack / 248 HP / 8 Sp. Def
EVs (If Jolly Nature): 252 Attack / 252 Speed / 4 Sp. Def
Moves:
- Precipice Blades: Your best ground STAB for a pure physically attacking set.
- Fire Punch: Your best fire STAB for a pure physically attacking set, very powerful under sun.
- Stone Edge: Your best coverage move, hitting everything super-effectively that you could not before.
- A set-up move of your choice, either Swords Dance for more power and Intimidate Cancelling, or Rock Polish to double your speed. You decide which would work best for your situation.
If you want a Special heavy damage dealer, then I would go for this set:
Groudon @ Red Orb
Nature: Preferably Modest Nature, but several others would work (such as Quiet, other special attack increasing natures, purely defense impacting natures, Timid, natures with no impact on stats).
IVs: Best you can get
EVs (If any Nature listed above other than Timid): 252 Sp. Atk / 248 HP / 8 Sp. Def
EVs (If Timid Nature): 252 Sp. Atk / 252 Speed / 4 Sp. Def
Moves:
- Earth Power: Your best ground STAB for a pure specially attacking set.
- Lava Plume / Fire Blast: Lava Plume for better accuracy and a higher burn chance, Fire Blast for more power. If you choose to run Lava Plume, you could use an alternate EV spread of 252 Sp. Atk / 252 Sp. Def / 4 Def.
- Solar Beam / Rock Polish: This slot can be either Solar Beam to cover water and ground types that might come your way while your weather is still up, or Rock Polish to double your speed.
- Thunder / Rock Polish This slot can be either Thunder to surprise Primal Kyogre on the switch, or Rock Polish to double your speed.
This set can be run with both coverage moves and no rock polish, or with one coverage move and rock polish.
If you want a bulky status spreading tank, the use this set:
Groudon @ Red Orb
Nature: Pretty much anything
IVs: Best you can get
EVs: 248 HP / 252 Sp. Def OR 252 Def / 4 Attack OR 4 Sp. Atk
Moves:
- Lava Plume: A fairly strong STAB move that has a high chance to burn.
- Thunder Wave: A very annoying move I've seen on competitive Groudon, this paralyzes anything you don't have a reason enough to burn.
- Stealth Rock An entry Hazard move that damages opponents upon switching in.
- Precipice Blades A fairly strong STAB move that gets the job done when you need to attack.
And there you go!
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That just about covers every Primal Groudon set in my arsenal. I hope that I was of at least some help to you and other people.
If you still have your heart set on using Fissure, than replace one of the secondary moves on each set with it. (If you do though, I warn you that the set may not function as well and that you will likely be plagued by misses!)