Below is an extract I copied from the Eley website:
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With multiple years’ experience as ELEY’s UK Test Range Manager, to go alongside his team captaincy for England Small bore Shooting Union, Martyn Buttery knows how to extract accuracy from a Rim-fire barrel.

As head of ELEY’s Testing Facility, based at ELEY HQ in the UK, he has overseen hundreds of tests from Olympians, National as well as club shooters, to become a master on barrel maintenance.
Here, Martyn discusses his barrel cleaning regime and how it improves accuracy and performance.
“Shooting is a very challenging sport with so many different variables to manage, which emphasizes the importance to eliminate as many factors as possible…
After reviewing data from thousands of rifle tests worldwide and from my personal experiences of shooting, here are details on the cleaning procedure used at our ELEY Customer Test Range”.
How often should we be cleaning our firearms in order to maintain good accuracy?
“At ELEY, when testing a rifle, we note when it is cleaned and data is then collected on the fouling shots.
Our engineers have crunched the numbers and come to the conclusion that cleaning is good for Rim fire barrels.
Every barrel loses accuracy once it becomes dirty, although the point at which it loses accuracy is different for each barrel.
In almost all Rim-fire competitions, starting from a clean barrel, I would expect 100-150 shots before cleaning is required. After every match, you should be cleaning your rifle and most importantly, never start a competition with a dirty rifle!”
How should we actually clean the barrel?
“At our UK Test Range, we firstly put wet patches / VFG felts (This is your preference) through your barrel, with a good quality solvent cleaner.
Afterwards, we put dry patches through until clean. If this is still dirty after 5/6 passes. We will then add more cleaning fluid and dry’s through again until this is completely clean.
We then use tissue to clean around the crown / breach areas, as well as cotton buds to ensure no build-up of wax in the breach.
It is important and vital to clean your firearm in order to preserve and sustain the barrels performance.
Cleaning a rim fire is relatively easy. It can be done in just a couple of minutes, and is extremely beneficial for accuracy. If you are not currently cleaning your rifle on a regular basis, I strongly urge you to do so”.
Testing.
“If you’re testing your rifle with us at one of our testing facilities and have a preferred cleaning routine, we will be happy to follow it.
Your firearm is yours, and we will do everything we can to accommodate you and your experience with us.”
You can book your UK or German visit via our ELEY VIP App: www.eley.co.uk/vip"