HW100 (all Models)

HW100 (all Models)

Choose an option from the list above...
  • Lightweight Cylinder Body
  • RAT Works Quick Fill End
  • New Style Biathlon Lever
  • Standard Fill Probe
  • Quick Connect Fill Probe
  • Extra Magazine x1
  • QD Sling Stud (replaces front stock bolt)


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HW100 (all Models)

The HW100 is arguably the best hunting/sporter air rifle that has ever been produced for UK shooters, it has remained largely unchanged for many years, that itself is a fine testament to its design and manufacturing. They are without doubt one of the best rifles money can buy in terms of their quality, performance and value for money.

Please read the information below regarding the work we do. To book your air rifle in please fill out the options at the bottom of this page. Once you have filled everything out, add the work to your basket and proceed to the checkout. If you'd prefer us to book you in please give us a call.

Main Work 

Tench Regulator & Tune (Includes a full service)

The work done in the Tench Regulator and Tune does everything possible to increase the ‘mechanical accuracy’ of your HW100. Making sure the pellets journey through the rifle is as friendly as possible to give the most chance of being accurate. The way the air is delivered to the pellet in the rifle after our tuning work is done can help improve the trajectory and windage characteristics of your pellets too, this helps give a more repeatable and favourable ‘in the field accuracy’ to your setup.

As part of fitting a Tench regulator and tuning the rifle we also carry out a service with all orings changed. The action is extensively worked on to increase the overall feel of the rifle, performance and efficiency. After the regulator is fitted and the tune carried out you can expect a shot-to-shot consistency of single figures as soon as the rifle has been worked on.

When fitting a Tench regulator and tuning the rifle we also engrave the breech block with our RAT WORKS logo as a way of showing that your rifle has been regulated and tuned by us, this is free of charge as part of the work. 

From January 2023 your power & consistency report is sent to you via email. This is done through our SKAN chronograph, the rifle is held in a mount to guarantee accurate results. The consistency will improve further as the rifle is used.

The Tench Regulator & Tune package is designed to make your rifle more consistent and air efficient, not more powerful. All sub 12 (non FAC) rifles are set to around 11.5ft/lbs after any work is done, keeping you well within the legal limit. 

Below is a list of all the work undertaken as part of the tune.

Fill Pressure, after work
Expected shot count, after work
HW100 Carbine
250 BAR
100 - 120
HW100 Rifle
250 BAR
180 - 200

Hammer Mechanism

  • Ensure the assembly is free of any oil, grease or debris which can cause consistency issues
  • Hammer modified for efficiency
  • The original Anti Tamper is removed to allow correct power setting of the hammer after conversion
  • Hammer spring ground and polished to help increase consistency and power stability

Loading assembly

  • Lubricant is added to parts of the assembly to allow a smoother action
  • The assembly is checked for straightness and any damage that could cause accuracy issues

Exhaust valve, transfer port & barrel

  • The exhaust valve stem assembly is modified to run more efficiently
  • Crown of the barrel re-cut the to increase the rifles accuracy
  • Transfer port and barrel are secured correctly within the assembly

Trigger assembly

  • Trigger let-off is set to a comfortable and safe amount. Any rifle that fails a drop test onto the work bench will have the trigger second stage increased to make sure it does not fire when dropped onto a bench.
  • Sears are inspected for damage and replaced if required, the sears are generally of an excellent quality finish so there is rarely any need to modify them beyond the factory finish.


Please note the following for the HW100 Models specifically:

We are unable to work on any HW100s with A&M Cylinders, bottle conversions or aftermarket regulators as we are unable give the the HW100 our warranty with these aftermarket parts fitted. 

After a Tench Regulator has been fitted to your rifle you will be unable to unscrew your cylinder when pressurised as the standard valve is removed and replaced with the Tench Regulator unit. Removing the cylinder with a Tench regulator in should be done with caution as it will invalidate your warranty unless authorised. 

Full Service 

The full-service strips and rebuilds your rifle replacing all seals and renewing any worn parts to revamp performance while sorting any problems you may have such as leaks, low power, poor shot count or other faults.

Service and Upgrade - Previously RAT Works tuned air rifles only

Our service and upgrade package is for air rifles that have previously had the Tench Regulator and tune package. With a service and upgrade we will replace all the orings in the air rifle as well as applying our latest tuning formula and upgraded parts. We will often recommend this if the air rifle in questions hasn't been to us in 12 months or more as we ar constantly improving our work.

On top of the main work that we carry out their are a number of optional modifications and extras we can also do while your air rifle is with us for work, these are explained below.

RAT Works Lightweight Cylinder Body 

Please note, this only replaces the 'middle part' of your cylinder, you will keep your original HW Gauge and QF unit. This lightweight cylinder body is 50% lighter than the original Weihrauch one to improve balance and reduce overall weight. The Lightweight cylinder body does not offer any other performance benefits. 

RAT Works Replacement Quick Fill Ends

These quick fill ends are a direct replacement for the standard end, fitted with a RAT Works pressure gauge and the QF Valve design designed to stop dust and dirt from entering your air cylinder to eliminate the chance of contamination and leaks. They use the standard HW100 fill probe to fill.

These ends can also be fitted to MK1 HW100 to be able to fill the air rifle without having to take the cylinder on and off.

Stock Engraving

We can engrave either our logo or a logo/image of your choice, this can only be done on wooden/laminate stocks only, the Plastic or Soft touch stocks cannot be engraved.

Please click here for all engraving options.



Cerakote is a thin film epoxy coating that will protect parts from corrosion. Cerakote is available in a range of colours and can be applied to almost anything.

For more information, please click here

If you have any questions regarding the work please get in touch.