Find the baseline behind every seating-depth decision.
The distance to the lands is different in every rifle—and it can change as the barrel wears. The Sigma8 CBTO Seating Depth Gauge helps you measure that starting point, giving you the baseline needed to make informed seating-depth adjustments.
Its stainless-steel body houses a hardened sliding rod secured by a brass thumb screw. The brass screw holds the measurement without damaging the rod through repeated use.
Pair it with a Sigma8 Bullet Comparator to set your desired bullet jump and confirm your finished cartridge measurements.
Requires a modified case matched to your cartridge.