Boros Moxite plays a meaningful artifact density with Melded Moxite, Rustvale Bridge, Ancient Den, Great Furnace, Lembas, and Ragged Short Spear, giving Ancient Grudge real targets to destroy, though note the Bridge lands are indestructible and will survive. Red Elemental Blast stays in the sideboard since this mirror-adjacent deck has no blue spells or permanents. We leave our core engine of Writhing Chrysalis, Malevolent Rumble, and the Gates untouched since those are our primary path to grinding out an edge in this fair matchup. Trimming Bitter Reunion for Ancient Grudge gives us a sharper way to disrupt their artifact synergies like Melded Moxite's Robot token production or their equipment plan.