Boost your big-game rifle builds and barrel work with the Rimmed & Belted Rifle Chambering Reamer – Clymer .338 Winchester Magnum Finisher, F338WIN. Purpose-built for professional gunsmiths and serious builders, this high-precision finisher reamer allows you to cut SAAMI-spec .338 Win Mag chambers that deliver reliable feeding, safe pressures, and the kind of accuracy hunters expect from a premium magnum rifle.
Whether you’re chambering a brand-new barrel or cleaning up an existing one, the F338WIN is the go-to tool for true, concentric, match-quality chambers in this legendary big-game cartridge.
Precision .338 Winchester Magnum Chambering Reamer
The F338WIN model is a dedicated finisher reamer for the .338 Winchester Magnum, one of the most respected long-range and big-game cartridges ever developed.
Cartridge: .338 Winchester Magnum
Type: Rimmed & Belted Rifle Chambering Reamer – Finisher
Use: Cutting final-dimension chambers to SAAMI specifications
From North American elk and moose to African plains game, the .338 Win Mag demands a properly cut chamber to show its full potential in accuracy and terminal performance. This reamer ensures your custom or rebarreled rifle is ready for premium ammo and serious field use.
Finisher Reamer – Final-Dimension, SAAMI-Spec Cut
Clymer’s finisher reamers are designed to cut a chamber to its final size and shape, including the body and neck, and typically the throat/leade:
Ideal for final chambering in new barrels
Perfect for small shops and individual builds where one high-quality tool will do the full job
Provides a smooth, accurate, SAAMI-correct chamber when used with proper technique, lubrication, and headspace gauges
If you’re only cutting a handful of .338 Win Mag chambers, you can often work exclusively with a finisher reamer like the F338WIN (rather than a rougher/finisher pair), while still achieving excellent results.
Built from Premium M-7 High-Speed Steel
Like other Clymer Rimmed & Belted rifle reamers, the F338WIN is manufactured from M-7 high-speed steel, chosen for its durability and ability to hold a sharp cutting edge:
Material: M-7 HSS – hardened and drawn for long service life
Designed for use with cutting oil and proper feeds on a lathe or suitable chambering setup
Built to withstand multiple chamber cuts while maintaining geometry and surface finish quality
With proper care, a Clymer M-7 reamer can provide years of service and multiple barrels’ worth of precise chambering work.
Professional Reamer Geometry – Smooth, Stable Cutting
Clymer’s Rimmed & Belted Rifle Chambering Reamers follow a proven professional geometry (details may vary slightly by specific model, but typically include):
Straight, right-hand flutes for efficient, stable chip removal
Throat/leade geometry matched to SAAMI .338 Win Mag dimensions for consistent bullet alignment into the rifling
Pilot and body design aimed at maintaining concentricity between chamber and bore
The result is a clean, accurate chamber with a surface finish that requires minimal additional polishing, while helping ensure consistent brass life and safe operating pressures.
Standard Shank & Drive for Easy Setup
As with most Clymer rifle chambering reamers, the F338WIN is designed to work with common gunsmithing tooling:
This makes it a straightforward addition to your existing chambering workflow, whether you’re using a full lathe setup or a specialized chambering fixture with proper alignment and support.
Ideal for Custom, Hunting & Long-Range Builds
The .338 Winchester Magnum remains a favorite among big-game and long-range hunters, and a properly cut chamber is essential for:
Custom hunting rifles built on long actions for elk, moose, bear, and African plains game
Upgraded factory barrels where accuracy and reliability are paramount
Long-range hunting rigs that demand consistent chamber dimensions for precise handloads
Using a quality reamer like the F338WIN helps ensure your rifle can take full advantage of premium bullets and powders, delivering tight groups and reliable field performance.
Best Practices & Safety Notes
As with any chambering operation, the F338WIN should be used only by qualified, experienced gunsmiths with proper tooling:
Always use correct headspace gauges for .338 Winchester Magnum
Ensure the barrel is properly indicated in the lathe and fully supported
Use appropriate cutting oil, light, controlled feed, and frequent clearing of chips
Thoroughly clean and inspect the chamber, and verify headspace before test firing
Following proper procedures helps ensure safe, reliable, and accurate chambers for your customers or personal builds.
Key Specifications – RIMMED & BELTED RIFLE CHAMBERING REAMERS F338WIN
Product Line: Rimmed & Belted Rifle Chambering Reamers
Model: F338WIN – .338 Winchester Magnum Finisher Chamber Reamer
Cartridge: .338 Winchester Magnum
Type: Finisher-style chamber reamer
Material: M-7 high-speed steel
Cut: Final chamber dimensions (SAAMI-spec, including neck and throat)
Application: Professional gunsmithing – chambering new barrels or correcting/.rebarreling existing rifles
(Exact flute count, pilot configuration, and shank dimensions follow Clymer’s standard rifle reamer design for rimmed/belted cartridges in this line.)
Why Choose the F338WIN .338 Win Mag Finisher Reamer?
Cartridge-specific design for the popular .338 Winchester Magnum
SAAMI-spec finisher reamer, ideal for final chambering work
Built from M-7 high-speed steel for superior tool life and cutting performance
Manufactured to professional gunsmith standards, delivering clean, concentric chambers
Perfect for custom big-game builds, long-range hunting rifles, and quality rebarrel jobs
If your shop builds or maintains serious .338 Win Mag rifles, the RIMMED & BELTED RIFLE CHAMBERING REAMERS F338WIN is the precision tool you need for cutting accurate, reliable chambers that hunters and shooters can trust in the field.
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