GILCHRIST PRECISION CHOKE REAMER 170100104

The Gilchrist Precision Choke Reamer 170100104 is a professional-grade, expandable shotgun choke reamer designed for gunsmiths and serious shooters who want precise choke control in 12 and 16 gauge barrels. Manufactured by Chadwick & Trefethen, this reamer is built to fine-tune constriction for better patterns or remove factory choke before installing screw-in choke tubes, all while maintaining perfect alignment with the bore. Brownells UK+3Yellowstone Armory+3Primary Tactical+3

Entering the barrel through the breech and piloting off the bore with tooling bushings, the Gilchrist reamer provides a controlled, centered cut that helps protect barrel integrity and delivers repeatable, professional results. Primary Tactical+2Brownells+2

Key Features – Gilchrist Precision Choke Reamer 170100104

• Manufacturer: Chadwick & Trefethen

• Model: Gilchrist Precision Choke Reamer

• Part Number: 170100104 Yellowstone Armory+2Brownells+2

• Gauge Range: 12 & 16 gauge “D” reamer – ideal for tight 12 ga and 16 ga choke work Brownells+1

• Expansion Range (approx.): 12 ga “D” reamer covers roughly .656" – .718" diameter, suitable for common field and tight chokes Primary Tactical+1

• Design: Expandable, angle-blade reamer for controlled metal removal and fine choke adjustment Primary Tactical+2Brownells+2

• Entry: Enters from the breech and pilots off the bore for precise alignment

• Material: High-quality steel construction for long tool life Primary Tactical+1

• Length: Reamer body approx. 13" long; designed to be used with the separate Gilchrist handle (about 25½") Primary Tactical+1

• Supports: Pattern tuning, choke opening, or pre-cutting fixed chokes prior to installing screw-in tubes

Expandable Angle-Blade Design for Precision Choke Control

The Gilchrist Precision Choke Reamer uses an expandable, angle-blade design that allows you to remove metal gradually and evenly inside the choke area. Brownells UK+3Primary Tactical+3Brownells+3

What that means in practice:

• You can incrementally open up a tight choke to the exact constriction you want instead of being stuck with factory dimensions.

• Fine-tune patterns for trap, skeet, sporting clays, turkey, or waterfowl by dialing in the choke to your load and shooting style.

• Safely remove or reduce fixed choke in preparation for threaded choke tube installation, rather than replacing the barrel.

For gunsmiths who demand measured, controlled metal removal, this adjustable, angle-blade system gives far more finesse than fixed-size reamers.

Optimized for 12 & 16 Gauge – “D” Choke Range

The 170100104 version of the Gilchrist reamer is a “D” size tool designed for 12 and 16 gauge barrels. Brownells+1

According to manufacturer specs, “D” reamers cover an expansion range of about .656" to .718", making this model well-suited for: Primary Tactical+1

• Tight-choked 12 gauge barrels that need to be opened gradually

• 16 gauge barrels in similar constriction ranges

• Step-by-step progression when moving from very tight to more open constrictions (often used before an “E” reamer if more opening is required on some 12 ga barrels) Brownells

This choke reamer gives you a wide working window to customize constriction for different disciplines and ammunition types.

Breech-Entry Design – Perfect Cutter-to-Bore Alignment

Unlike crude tools that enter from the muzzle without proper guidance, the Gilchrist Precision Choke Reamer is designed to enter through the breech and pilot off the bore using Clymer Choke Tooling Bushings. Primary Tactical+2Brownells+2

Benefits of the breech-entry system:

• Precise cutter alignment with the true bore axis, reducing risk of eccentric cuts

• Better protection of muzzle crown and exterior finish, since the tool is guided from inside

• Smoother, straighter reaming that preserves the barrel’s structural and cosmetic integrity

For high-end shotguns, classic doubles, and customer guns where mistakes are not an option, this alignment system is a major advantage.

Requires Gilchrist Handle & Clymer Bushings (Sold Separately)

To use the Gilchrist Precision Choke Reamer 170100104, you’ll need a few dedicated accessories (not included with the reamer): Primary Tactical+2Brownells+2

1. Gilchrist Handle

   • Approximately 25½" long for plenty of leverage and fine control. Primary Tactical+1

2. Two Clymer Choke Tooling Bushings

   • Installed on the reamer to center the cutter in the bore.

   • Bushings are selected by gauge and bore diameter using Clymer’s bushing chart. Primary Tactical+1

This modular approach lets you use one handle and multiple reamers/bushing sets to service a full range of 12 and 20 gauge choke applications, maximizing versatility and value in a gunsmithing shop.

Professional-Grade Steel Construction

Built from high-quality steel, the Gilchrist reamer is engineered to stand up to repeated use in a professional environment. Primary Tactical+1

• The robust cutter body and blades maintain sharpness across multiple jobs when properly lubricated and cared for.

• Steel construction handles the torsional forces involved in choke reaming without twisting or chattering when used correctly with proper bushings and cutting oil.

For gunsmiths, that durability translates to consistent performance and a long service life from a single tool.

Ideal Users & Applications

The Gilchrist Precision Choke Reamer 170100104 is ideal for:

• Professional gunsmiths doing choke work on 12 and 16 gauge shotguns

• Shotgun specialists converting fixed-choke barrels to screw-in choke systems

• Pattern-obsessed clay shooters or hunters working with a gunsmith to fine-tune constriction for specific loads

• Restoration and custom projects on classic or competition shotguns where choke geometry matters

If your work demands accurate, repeatable choke adjustments rather than swapping barrels or guessing with factory constrictions, this tool belongs in your choke tooling lineup.

Technical Specifications – Gilchrist Precision Choke Reamer 170100104

• Product: Gilchrist Precision Choke Reamer

• Manufacturer: Chadwick & Trefethen Yellowstone Armory+2Brownells+2

• Part Number: 170100104

• Tool Type: Expandable, angle-blade choke reamer

• Gauge Coverage: 12 & 16 gauge (Size “D”)

• Approx. Expansion Range: .656" – .718" (12 ga D range) Primary Tactical+1

• Material: Steel

• Reamer Length: ~13" Primary Tactical+1

• Handle (Required, Sold Separately): Gilchrist handle, ~25½"

• Bushings (Required, Sold Separately): Two Clymer choke tooling bushings per job, selected by gauge/bore diameter Primary Tactical+2Brownells+2

• Use: Fine choke adjustment, pattern tuning, fixed choke removal prior to screw-in choke tube installation

Why Choose the Gilchrist Precision Choke Reamer 170100104?

If you’re searching for “Gilchrist Precision Choke Reamer 170100104”, “Chadwick & Trefethen 12 gauge choke reamer”, or a truly precise tool for professional choke work, this model stands out because it offers:

• A breech-entry, bore-piloted design for superior alignment and barrel safety

• Expandable angle-blade geometry that lets you fine-tune constriction instead of settling for fixed sizes

• Dedicated 12/16 gauge “D” range coverage—perfect for tight 12 ga barrels and 16 ga choke work

• Compatibility with the Gilchrist handle and Clymer bushings for a complete, modular choke tooling system

For gunsmiths and advanced shotgun enthusiasts who demand precision choke control and professional results, the Gilchrist Precision Choke Reamer 170100104 is a proven, shop-ready solution.

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