The Forster Rimmed and Belted Headspace Gauge in 7.62x54R Russian NO-GO (brand part no. BG762RN) is a precision chamber-checking tool for Mosin-Nagant and other rimmed 7.62x54R rifle actions. Every gunsmith knows that a headspace gauge is the most reliable way to confirm the length of a rifle chamber. Headspace is the distance between the face of the breech and the base of the cartridge when the action is closed, and excessive headspace can be dangerous as well as harmful to accuracy: unsupported brass fired in a chamber with too much headspace can rupture, sending gas rearward like exhaust from a rocket. Because your safety is on the line, Forster builds these gauges to exacting manufacturing standards.

Key Specifications

• Chambered specifically as a NO-GO gauge for verifying that a 7.62x54R rimmed and belted chamber has not been cut with excessive headspace.
• Precision length of 0.5 inches for accurate, repeatable chamber checks.
• Supplied as a single gauge ready to drop into the chamber for testing.
• Weighs approximately 0.08 pounds, light enough to carry in a range bag or tool kit.

Frequently Asked Questions

What does it mean if my bolt closes on this NO-GO gauge? If the rifle’s bolt closes on a GO gauge, the chamber will safely accept ammunition built to SAAMI industry-standard dimensions. If the bolt closes on a NO-GO gauge, the chamber may already have excessive headspace, and if it closes on a FIELD gauge the chamber is dangerously close to, or already beyond, the maximum SAAMI-specified size. Most gunsmiths aim to keep a chamber cut somewhere between the GO and NO-GO dimensions.

Is this gauge specific to one cartridge? Yes, it’s ground to the rimmed and belted 7.62x54R Russian dimension, so it should only be used to check chambers cut for that cartridge.

Buy the Forster Rimmed and Belted Headspace Gauge, 7.62x54R Russian NO-GO

Whether you’re building a Mosin-Nagant-pattern rifle or verifying a rebarrel job, this gauge takes the guesswork out of confirming chamber safety. Find it in our reloading equipment lineup, and our Lubbock, Texas team will get it shipped quickly.