S3/4/5 Series (Inc. HFT 500, S510 Ultimate sporter & TDR versions)

Please read the information below regarding the different work options. 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.

Main Work 

Regulator & Tune (Includes a full service)

The Regulator & Tune packages are 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.

When the work is done by the RAT Works the action is extensively worked on to increase the performance, efficiency, accuracy and overall feel of the rifle. Almost every aspect of the rifle is modified, changed or enhanced in some way.

Air Arms

Fill Pressure when Tench Regulated







S4/5*0 Carbine




S4/5*0 Rifle








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

Hammer Mechanism

- Ensure the assembly is free of any oil, grease or debris which can cause consistency issues

- Re-finish hammer spring to a higher accuracy

- Polish the bearing surfaces in the hammer

- Hammer/trigger sear mating face is modified if needed

- The Hammer spring is considerably shortened to reduce the power after the regulator is fitted, this makes cocking effort much less and puts much less pressure on the trigger sears, allowing a much crisper and responsive second stage.

Loading assembly

- Loading probe modified for pellet feed and smoothness

- Bearing surfaces polished

- If you include the magazine in with your rifle they are also modified to remove any loading issues such as jamming whilst cycling

- Lubricant is added to parts of the assembly to allow a smoother action

- Bolt lock up mechanism is usually modified for more responsive and smoother movement, also increasing the rifles consistency.

Exhaust valve, transfer port & barrel

- The exhaust valve stem assembly is modified to run more efficiently

- Valve body is modified for better airflow through the firing cycle increasing efficiency

- The valve pressure is reset to give a better performance between heavy and lighter pellets

- The transfer port is modified to give a higher degree of air flow efficiency

- Crown of the barrel re-cut or polished if needed to increase the rifles accuracy

- Transfer port and barrel are aligned correctly

- The Adjuster in the transfer port is set with minimum restriction to allow a much more efficient use of air, 90% of the power setting is done with the hammer spring shortening. Only the final setting is done on this adjuster, which also helps with the FPS variance.

Trigger assembly

- Sears are polished to a smoother finish if needed

- Hammer engagement sear modified if needed to smoother let off

- Trigger let-off is set to a comfortable and safe amount.

Some parts may be chargeable although I do replace many damaged parts for free as standard. 

O-ring seals are replaced as standard throughout the rifle and refitted with the correct lubrication.

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. A report sheet will be included with the rifle once work is complete detailing the shot to shot consistency through our SKAN chronograph, the rifle is held correctly in a mount to guarantee accurate results.  This consistency will improve further as the rifle is used.

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.

We now replace the firing valve and reface the valve seat as part of the full service. 

PLEASE NOTE: We are not able to work on rifles fitted with aftermarket regulators other than ones we have fitted ourselves.

Important Gauge Information!

Once your rifle has been fitted with a regulator, the original fill gauge will read regulator pressure and not fill pressure. This is due to the location of the regulator and the standard gauge. We will blank your original gauge off with a RAT Works sticker so the gauge is no longer readable.

If you require the ability to read fill pressure from your rifle please select the "Quickfill & Gauge" option below.

Safe practice is to always observe the gauge on your air bottle/dive bottle and ensure that when filling your rifle that the gauge reading does not exceed your rifle's safe working pressure.

Stock Engraving

We can engrave either our logo or a logo/image of your choice, this can only be done on wooden/laminate stock.

For all Engraving options please click here


Getting your air rifle to us

Whether you would like to use our courier collection & return service or you would like to drop the air rifle in person. You will need to read through our delivery information by 
clicking here

Choose an option from the list above...


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