The Hornady Lock-N-Load Modified Case in .300 Weatherby Magnum (A Series, part no. A300W) is specially machined to work with Hornady’s Lock-N-Load Precision gauges, not to be loaded and fired. A fine thread at the case head attaches it squarely to the gauge, and the neck is machined perfectly round and opened just enough to slip a standard bullet in without binding, so your readings stay consistent from one measurement to the next. Reloaders who track headspace and cartridge overall length on .300 Weatherby Magnum brass rely on a caliber-correct modified case exactly like this to keep those numbers trustworthy at the bench.

Key Specifications

• .300 Weatherby Magnum chambering, A Series, threaded to fit Hornady Lock-N-Load Precision gauges.
• Case neck machined perfectly round and slightly opened to accept a standard bullet without binding.
• Threaded at the case head for a secure, repeatable mount on the gauge.
• Comes ready to thread directly onto your LNL gauge — no fitting or modification needed.
• Gives a fixed, caliber-correct reference so readings stay comparable across sessions.

Frequently Asked Questions

What is this used for? It threads onto a Hornady Lock-N-Load Precision gauge to give you a repeatable, caliber-specific reference for headspace and cartridge overall length measurements.

Can I load and fire this case? No — it’s a modified gauge accessory machined to mate with Hornady’s LNL measuring tools, not a case meant for loaded ammunition.

Buy the Hornady Lock-N-Load Modified Case, A Series, .300 Weatherby Magnum

Keep your measurements accurate and repeatable with the correct caliber-matched accessory. Order from our Lubbock, Texas gun shop for fast, insured shipping, and browse the rest of our reloading equipment selection.