HORNADY 380718 300 WIN MAG CARTRIDGE GAUGE

The Hornady 300 Win Mag Cartridge Gauge (380718) is a Lock-N-Load go/no-go style case gauge that lets you verify your sized brass and loaded 300 Winchester Magnum ammunition will fit correctly in a SAAMI spec chamber. This Hornady 380718 300 Win Mag cartridge gauge works as a quick bench tool for checking headspace and case length on your 300 Win Mag reloads.

Key Features

• Manufacturer part number: 380718
• Cartridge: 300 Winchester Magnum (.308 diameter)
• Product type: Lock-N-Load cartridge gauge
• Function: checks sized cases and loaded cartridges for correct fit in SAAMI spec chambers
• Gauge style: go/no-go style drop-in gauge
• Construction: machined metal body designed for 300 Win Mag profile
• Compatibility: works with empty sized brass and complete loaded rounds in 300 Win Mag
• Use case: verification of headspace and case length against a SAAMI reference

Special Features

• Drop a case or loaded round into the gauge to confirm it sits flush within the machined windows, giving you an immediate visual pass/fail on sizing and trimming.
• The internal profile mirrors a SAAMI chamber, which helps you catch cases that are too long or not sized enough before they cause hard chambering.
• The one-piece gauge body has no moving parts, so it rides along on the bench as a durable reference tool for repeated checks across many loading sessions.
• The 380718 gauge focuses on 300 Win Mag only, which gives you a dedicated, cartridge-specific reference instead of a universal multi-caliber compromise.

Practical Benefits

• The Hornady 300 Win Mag Cartridge Gauge (380718) helps you spot headspace and length issues at the bench so your 300 Win Mag ammo chambers smoothly instead of tying up the rifle.
• You can use this gauge to sort questionable brass and verify that resized cases and finished rounds work with typical SAAMI chambers, reducing time lost to test cycling ammunition in the rifle.
• As you adjust your sizing die and trimmer, the gauge gives you a consistent reference, so your setup stays tuned to reliable chambering for hunting, match, or practice loads in 300 Win Mag.