In Old School RuneScape, cannonball production has become one of the most time-efficient semi-AFK money-and-supply loops in the game, especially after recent updates introducing specialized processing locations and NPC support systems. The addition of the NPC Isisles and the ancient furnace on Grimstone significantly changes how players approach cannonball crafting, particularly when combined with the double ammo mold from Giants’ Foundry, with broader economy discussions occasionally touching on buy OSRS gold as players compare in-game efficiency versus external progression shortcuts.

At its core, the method revolves around converting steel bars into cannonballs at drastically improved speeds. Traditionally, smelting cannonballs was one of the slowest Smithing activities in the game, constrained by long action timers and frequent banking. However, modern updates have compressed both the action cycle and logistical overhead, allowing players to generate far more output per hour with less downtime.

Unlocking Isisles and Accessing Grimstone

Before you can use the enhanced method, you must unlock Isisles. He is not available by default and must be recruited through a short travel sequence. Players begin by traveling to Port Roberts, which is most efficiently reached using the Sailor’s Amulet. From there, you head north to locate Isisles, an NPC motivated by relocating to Grimstone due to perceived economic opportunity.

After initiating dialogue, Isisles boards your ship, but he does not automatically travel to Grimstone. Instead, you must either sail manually or use the summon boat spell, provided you have a teleport focus installed on your ship and sufficient Sailing level. Once transported, Isisles relocates into the Grimstone dungeon furnace area, confirmed by an in-game message indicating he has “found a warm place to work.”

The Ancient Furnace Advantage

The ancient furnace is the core of the efficiency boost. Normally, cannonball production operates on a 10-tick cycle, making it relatively slow. The furnace halves this to 5 ticks, effectively doubling processing speed. Since each game tick equals roughly 6 seconds, each action becomes significantly faster in real time.

When paired with the double ammo mold, the process becomes even more optimized. The mold does not increase output per bar; instead, it processes bars in pairs, reducing interaction frequency and effectively doubling throughput efficiency. This synergy reduces the overall time per inventory cycle dramatically.

With full optimization, one inventory cycle can be completed in roughly 36 seconds of active time, excluding minor movement or interaction delays. This turns cannonball production into a highly repeatable loop of banking, teleporting, and processing.

Production Efficiency and Output Scaling

The evolution of cannonball production efficiency can be broken into distinct eras:

· Early game method: ~2,400 cannonballs per hour

· Pre-ancient furnace with double mold: ~4,300 per hour

· Ancient furnace era: ~6,000 per hour

· Full optimization with Isisles: ~8,600 per hour

This final stage represents a near fourfold increase over legacy methods. The improvement comes not only from faster smelting but also from reduced banking friction and NPC-based unnoting, which eliminates several intermediate steps.

Isisles plays a key role by unnoting steel bars at a fixed cost of 100 GP per bar type applicable to cannonball production. This removes the need for repeated bank withdrawals, especially beneficial for Ironman accounts or high-volume production runs.

Profitability and Practical Use

From a gold efficiency standpoint, cannonball production can yield a modest but consistent profit margin when using optimized setups. However, the primary value is not raw GP—it is time conversion. Players trade gold and attention for combat readiness, particularly for Slayer training or boss encounters where cannon usage significantly increases kill speed.

On Ironman accounts, cannonballs are especially valuable due to their impact on Slayer progression. While Smithing XP is relatively low compared to alternatives like Giants’ Foundry, the ability to generate thousands of cannonballs per hour makes the method strategically important.

Strategic Considerations

The decision to use Isisles depends on account goals. For maximum efficiency, players should minimize downtime between furnace cycles and ensure inventory routing is optimized via teleportation methods such as fairy rings or home teleports. Any delay in banking or travel reduces the gains from the furnace’s improved tick rate.

Ultimately, cannonball production in its current state represents a shift from an AFK crafting activity to a semi-active efficiency loop. Players who optimize movement, inventory handling, and NPC usage can achieve industry-leading output rates, making it one of the most refined Smithing-adjacent systems in the game, and it is sometimes discussed in relation to cheap RS gold within broader player economy comparisons.