Chamber Reamers & Headspace Gauges

Precision tools made to civilian C.I.P. and SAAMI chamber specifications
Shop now
Hamerton chamber reamer crossed with a headspace gauge
Chamber reamer & headspace gauge
About us

Hammerton is one of the largest suppliers and manufacturers of chamber reamers and headspace gauges. All the tools are crafted using specially selected carbide grades, chosen meticulously during the design process to guarantee precision cutting edges.

Read more
Enhanced Quality

Improved part quality with superior finishes

Consistent Results

Tool-to-tool performance reliability

Fast Turnaround

Excellent lead times to meet your needs

Cost-Effective

High quality at a competitive price

secure payment for goods via PayPal

Shop now
Headspace GO-NO-GO
Hamerton GO and NO-GO headspace gauge set, crossed pair
Chamber reamer
Advantages
01 /

High-precision chamber reamers are custom-made to meet your exact specifications, ensuring exceptional performance and precision.

02 /

Finish chamber reamers are crafted from specialized carbide grades, carefully selected during the design phase to deliver superior cutting edges.

03 /

GO and NO-GO headspace gauge sets let you verify the finished chamber, confirming that standard factory ammunition will chamber safely.

04 /

Hammerton tools are made to C.I.P. and SAAMI civilian standards and hold precise tolerances, ensuring high-quality and reliable performance.

Frequently asked
questions
FAQ
  • 01
    What is a headspace gauge set?

    A headspace gauge set (GO and NO-GO) is a precision gunsmithing tool used to measure the distance from the bolt face to the datum line of the chamber. The bolt should close on the GO gauge, confirming that standard factory ammunition chambers safely, and should not close on the NO-GO gauge, which marks the tight maximum limit gunsmiths work to when cutting a new chamber.

  • 02
    How does a chamber reamer work?

    A chamber reamer is a specialized fluted tool used to precisely cut the chamber of a barrel. The process involves inserting the reamer into the bore while the barrel rotates around it, usually using a lathe. This technique ensures the chamber is shaped to exact specifications, allowing for proper cartridge fitting and function.

  • 03
    What is the difference between reamer and drilling?

    IDrilling, boring, and reaming each play a unique role in hole-making. Drilling is the first step, creating a basic hole. Boring then enlarges and shapes it to the desired size. Finally, reaming finishes the hole, providing precision dimensions and a smooth, accurate surface for optimal performance.

  • 04
    What is the rule for reaming?

    The general rule for reaming is to leave 0.010" to 0.015" of material after the drilling operation for the reamer to remove. For small diameters, like 1/32" or less, this should be reduced to 0.003" to 0.006". It's often more effective to use a percentage of the hole size rather than a fixed range for optimal results.

  • 05
    What is the principle of a reamer?

    A reamer works by being inserted into a pre-drilled hole that is slightly smaller than the final required size. As the reamer rotates, its cutting edges gradually remove a thin layer of material, enlarging the hole with precision and providing a smooth surface finish.

Payment & Delivery

Payment options:

Our website supports the following payment methods:

  • Cryptocurrency (USDT TRC20) – for payments in other cryptocurrencies please contact us via the feedback form and we will provide the required payment details.
  • Cryptocurrency (BTC)
  • Direct bank transfer – we provide details for local bank transfers in your currency (except the USA). Payments can also be made through Wise with any bank card, which only requires a simple 3-minute registration.
  • Payment via PayPal — you can pay with your credit card.

For customers from the USA we provide account details in pounds sterling for bank transfers, or you can use any bank card through Wise after a quick registration.

Our products are also available on eBay and Amazon.

Delivery information:

Manufacturing some custom tools can take up to 7 days. We ship worldwide by state air mail, and delivery takes from 14 to 30 days depending on your location. Once the parcel is dispatched, you will receive a tracking number.

Thank you for your purchase!

Hammerton is a leading manufacturer of precision tools for gunsmiths and barrel makers, specializing in finish chamber reamers and headspace gauge sets. Every tool we make is built to civilian commercial standards only, C.I.P. and SAAMI. We do not manufacture to NATO or any other military specification.

Chamber Reamers

Hammerton chamber reamers cut and finish the chamber to exact dimensional tolerances. They are available for a wide range of civilian calibres in both C.I.P. and SAAMI standards, from rimfire through to sporting rifle cartridges. Each reamer is ground from specially selected carbide grades, which holds a sharp cutting edge far longer than tool steel and leaves a clean surface finish in the chamber.

Headspace Gauge Set GO and NO-GO

A headspace gauge set is a precision gunsmithing tool that measures the distance from the bolt face to the datum line of the chamber. The GO gauge checks the minimum chamber depth, confirming that standard factory ammunition will chamber safely. The NO-GO gauge corresponds to the tighter maximum limit that gunsmiths work to when cutting a new chamber.

GO gauge. The bolt should close completely. The chamber meets the minimum dimension and standard factory ammunition will chamber safely.

NO-GO gauge. The bolt should not close. If it does, the chamber may have excessive headspace and needs further inspection. The absolute safety limit is a separate measurement, taken with a field gauge.

How to test

  1. Strip the bolt. Remove the extractor, ejector and firing pin assembly, so spring resistance does not skew the feel of the test.
  2. Insert the GO gauge into a clean chamber and gently close the bolt.
  3. Remove the GO gauge, insert the NO-GO gauge and attempt to close the bolt.
  4. A correctly cut chamber closes on GO and does not close on NO-GO.

Made to Your Specification

Tools are produced to your exact requirements, taking into account the cartridge standard, the barrel material and the finish you need. Custom dimensions and non-standard civilian chamberings are available on request: send us your drawing or the cartridge specification and we will quote it.

For precision chamber reamers and headspace gauges, Hammerton is your trusted partner. Contact us today to discuss your specific requirements!