The Hornady Lock-N-Load Cartridge Gauge, .223 Rem / 5.56 NATO (part number 380707), is a drop-in gauge that checks whether a fired case or a loaded round is within SAAMI chamber specification for .223 Rem / 5.56 NATO before it ever reaches a rifle. Reloaders drop a sized case or finished cartridge into the gauge; if it seats flush, the round will chamber cleanly, and if it doesn’t, you’ve caught an oversized case or a seating problem before a range trip or a stuck case in the field.

Key Specifications

• .223 Rem / 5.56 NATO-specific chamber gauge sized to this cartridge’s SAAMI chamber dimensions, not a universal fit.
• checks both fired brass and loaded ammunition so it works as a sizing-die check and a final QC step on finished rounds.
• drop-in, no-press design giving a pass/fail read by eye with no tools or setup required.
• catches over-length or over-sized rounds before the range helping avoid a stuck case or a failure to chamber in the field.
• silver-finished body for a durable, easy-to-read gauge that resists corrosion at the bench.
• ships at approximately 0.34 lb a compact gauge that adds minimal weight to a die box or range bag.

Frequently Asked Questions

Does this check loaded ammo, or only empty brass? Both. The gauge is built to check fired or resized brass as well as finished, loaded .223 Rem / 5.56 NATO cartridges.

What does it mean if a round doesn’t seat flush in the gauge? It indicates the case or round is outside SAAMI chamber spec for .223 Rem / 5.56 NATO and needs to be resized, trimmed, or set aside before it’s fired.

Buy the Hornady Lock-N-Load Cartridge Gauge, .223 Rem / 5.56 NATO

Order this .223 Rem / 5.56 NATO Cartridge Gauge from our Lubbock, TX gun shop with fast shipping to add a quick chamber check to your reloading bench. See our full reloading equipment lineup for more Lock-N-Load gear.