The Hornady Cartridge Gauge in .355 inch (Hornady part no. 380701) covers both 9mm Luger and 9×21, two cartridges close enough in dimension to share a single gauge, letting reloaders check cases and finished ammunition against SAAMI chamber specifications before firing. Part of Hornady’s Lock-N-Load line of cartridge gauges, it gives high-volume 9mm reloaders a fast pass/fail check that catches an oversized case or a seating error before it becomes a feed issue at the range. This is one of the highest-demand calibers to check in volume, and this gauge makes that a quick bench task rather than a chore.

Key Specifications

• Gauges cases and ammunition to 9mm Luger and 9×21 chamber dimensions.
• Checks fit against SAAMI chamber specifications.
• Part of Hornady’s Lock-N-Load cartridge gauge lineup.
• Ships at approximately 0.15 lb.
• A round that seats flush in the gauge falls within SAAMI chamber tolerances; one that does not should be set aside before firing.

Frequently Asked Questions

Does this gauge work for 9×21 as well as standard 9mm Luger? Yes, both cartridges share dimensions close enough for this single gauge.

How fast can a batch of 9mm be checked? It is a simple drop-in test, so a full batch can be verified in minutes.

Buy the Hornady Cartridge Gauge .355in, 9mm Luger/9×21

Confirm every 9mm Luger or 9×21 round chambers correctly before loading a magazine. Order from Hornady through our reloading equipment lineup, with fast shipping from our Lubbock, Texas gun shop.