Does Svellsongur give Ornn Forge God another instance of deflect 2 weaponmaster (can you equip another weapon for 1 power less and make Ornn deflect 4)?

Yes, equipping Svellsongur to Ornn, Forge God results in the total Deflect value on the unit becoming Deflect 4.

Here is the breakdown of how this interaction works based on the official rules and FAQs:

1. The Deflect 4 Interaction

• Copying Text: When Svellsongur is attached to Ornn, Forge God, it copies Ornn's rules text, which includes Deflect 2.
• Active Effect: While attached, the equipment’s effect text is active and is appended to the unit's rules text.
• Stacking Keywords: According to Rule 809.2, if a unit is granted Deflect from an additional source, the Deflect values sum together. Since Ornn already has Deflect 2 and now has an additional Deflect 2 granted by the equipment's active text, they sum to Deflect 4 (RiftJudge FAQ #8608).

2. Regarding Weaponmaster

Ornn, Forge God does indeed have the Weaponmaster keyword.

• How it works: When you play Ornn, you may choose an Equipment you control and pay its Equip cost at a discount (reduced by [A], or 1 generic power).
• Svellsongur's Interaction: You can use Ornn’s Weaponmaster trigger to attach Svellsongur (or any other equipment) to him for less power.
• Strategic Note: Once Ornn is already on the board, he is no longer "being played," so his Weaponmaster ability does not trigger again. However, if you have other ways to attach equipment (like the equipment's own [Equip] ability), you can continue to attach additional gear to him. Each piece of gear attached will contribute to his passive ability (+1 [S] for each friendly gear) and, if the gear copy effect happens to grant another instance of Deflect, that would stack further.

Important Reminders:

• Targeting: While Ornn has Deflect 4, keep in mind that Deflect only protects the unit. If an opponent targets the equipment (Svellsongur) directly (e.g., with a spell like Salvage), they do not have to pay the Deflect cost, because the protection applies to the unit, not the gear itself (RiftJudge FAQ #8843, #9176).