More Tacks is the first upgrade of Path 3 for the Tack Shooter in BTD6. It allows the Tack Shooter to shoot 10 tacks instead of 8. However, the arrangement will be different, making the Tack Shooter not be able to shoot directly horizontally, until Even More Tacks is bought. It costs $85 on Easy, $100 on Medium, $110 on Hard, and $120 on Impoppable.
Purchasing More Tacks will increase Ring of Fire and Inferno Ring's pierce by 10, despite neither upgrade sending out tacks. The same applies to Even More Tacks, except it's a total of +20 pierce compared to not getting the Path 3 upgrades.