L.E. Wilson Steel Neck Sizer Die Bushing .337 (B-337)

Description

The L.E. Wilson Steel Neck Sizer Die Bushing in .337 is the interchangeable insert that drops into your Wilson neck sizing die or Wilson bushing-type full-length die to control exactly how tightly the case neck grips the bullet. Instead of relying on an expander ball to do the work on the way out, the bushing sizes the neck to the diameter you choose, which means less brass getting worked over and more consistency round to round. Machined from steel, it holds its dimension through repeated sizing cycles.

Picking the Right .337 Bushing for Your Load

There's no universal size here, which is the whole point of a bushing system. The quick method is to measure the outside diameter of a loaded round at the neck where the bullet sits, then subtract .002 to .003 inches. That accounts for brass spring-back and leaves you with roughly .001 to .002 inches of grip on the bullet. The other way is to measure your neck wall thickness, multiply by two, add your bullet diameter, then subtract that same .002 to .003. Either path gets you to a number, and from there you grab the bushing that matches.

How the .337 Bushing Earns Its Keep

Consistent neck tension is one of those details that separates plinking loads from the stuff that prints tight groups. Because Wilson makes these in .001 inch increments, you can fine-tune grip for different bullets, brass lots, or hunting versus match loads without ever touching your die body. Want a firmer hold because your brass springs back harder? Step down a thousandth. The bushings freely interchange across Wilson bushing-type neck sizing dies, so building out a small set covers a lot of ground.

This is a single bushing sized at a nominal .337 inches, part number B-337. It's a favorite among precision reloaders and bench rest crowds for good reason, giving you real control over bullet seating without a lot of fuss. Measure, subtract, load, and let the groups tell the story.