When it’s all on the line, shoot with confidence—choose the FORTIS.

The FORTIS 4mm is Terra Firma’s original arrow, tested and proven over more than a decade of successful hunts. Built for serious bowhunters, this shaft delivers a clean balance of speed, precision, and toughness.

Its slim 4mm profile and dense carbon build give it a deadly combo of penetration and stability. Paired with the 60gr alloy outsert system, the FORTIS holds a high FOC for a heavyweight arrow, giving you powerful flight and consistent hits—even when smashing through bone.

This is the arrow that made the Terra Firma name. Reliable. Efficient. Ready for anything.

GPI + O.D PER SPINE

250 - 13.0 gpi - 6.71mm / .264"

300 - 10.8 gpi - 6.34mm / .250"

350 - 9.5 gpi - 6.13mm / .241"

400 - 8.6 gpi - 5.97mm / .235"

500 - 7.6 gpi - 5.77mm / .227"

SPECS

.001" Straightness Tolerance - Every arrow is precision laser checked and sorted meticulously until your 12 pack is perfect.

+/- 1gn Weight Tolerance - Advanced manufacturing and careful quality control ensures consistent weight for every shaft.

4mm / .166" Inner Diameter - Micro diameter for accuracy and wind cutting performance. Compatible with all .166 nocks and other components.

32" shaft length - Ready to be cut down and assembled to your preference.

PACKAGE INCLUDES

12x FORTIS Shafts.

12x FORTIS 60gn Alloy Outserts - Spine Matched. (Must be glued in prior to use)

12x TF .166 Nocks - Short profile and durable.

GPI (Grains Per Inch)

250 Spine - 13gpi

300 Spine - 10.8gpi

350 Spine - 9.5gpi

400 Spine - 8.6gpi

500 Spine - 7.7gpi

Outsert Weight - 60gn

All Shafts come at 31.5 Inch Length, Ready to Cut down.