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This is a collection of great tried & tested tips, tricks, guides & "how to" advice from our Service Engineers & Customers. This section will keep growing, so keep an eye on it!
This is a collection of great tried & tested tips, tricks and advice from our Service Engineers & Customers. This section will keep growing, so keep an eye on it!
It can be quite daunting the first time you attempt to service the HW100 yourself. Some of the most common mistakes people make are overtightening the gun when putting it back together, using the wrong tools or o-rings/seals or scratching the gun whilst trying to remove old orings. PLEASE be careful - the HW100 is a precision instrument. If you don't have the right tools or the confidence to attempt it yourself, please contact us or your local Gunsmith to do it for you.
One of our customers, Martin Healy has made a series of 3 You Tube videos on how to service your HW100. MANY of our customers have found them helpful...
Whilst we consider Napier pellet lube to be evil stuff and to be avoided at all costs, Napier Pull Through Barrel Cleaners are brilliant - clean your barrel every 500 to 1000 pellets.
Many people still believe that barrels should be “leaded” up. Whilst this is definitely true for Springers, it is not for PCP’s. Springers have an added ingredient that makes the lead on steel/lead on lead work.... particles of oil and grease. When you add oil or grease particles to the mix, the friction reduces massively - but a PCP uses pure clean air and as such there is nothing to lubricate the pellet down the barrel. Dry lead on lead is not very slippery at all.
In every PCP we own, we use LubroTek LT1. It is a dry lube (unlike the wet, Napier stuff) and as such you don’t get a sticky mess covering everything. By lubricating with LT1 you will get the same performance shot after shot. LT1 will give you a dry film lubricant to outperform any other pellet lube. Friction is lowered and there is a reduced level of pick-up of lead deposits from previously used pellets, leading to a reduction of fliers. In our experience (and many others) accuracy and consistency goes up by a good 15 – 20% when you use a dry lube.
How to use LT1: put 200 or so pellets in a sandwich bag and then add a couple of squirts of LT1 to the bag, seal it up and swill them around in the bag gently until all the pellets are covered. Pour out onto a plate (non-porous ceramic) and let them dry. Clean your barrel, then use the pellets as normal. Then clean your barrel every 500 – 1000 pellets. LT1 really isn’t just a pellet lube, it is a barrel lube for PCP’s.
PLEASE don't put your gun in water! That goes for the cylinder also... the cylinder ends may look like they are sealed, but the glass covering on the gauge end is just that, a covering. If you suspect a leak on your air cylinder, put a bit of air in it, take it off the gun & put a balloon over each end of the cylinder, make sure you cover the fill probe hole with the balloon and leave it for a few hours - if either of the balloons inflate, even slightly, you have a leak.
We have found that this leak detection fluid from B&Q (UK) is really handy stuff for your gun:-
Re-assembled the regulator block and now have a air leak down the barrel? The leak could be caused by low cylinder pressure if you fill your cylinder slowly or fit an empty air cylinder - the fix is to quickly introduce around 40 BAR into the cylinder. Because the valve spring alone does not apply sufficient pressure to complete the seal, it is aided by the regulated air pressure behind the exhaust valve. Also, be aware that some dive cylinders have restrictors already fitted into them that make the filling very slow. If this is the case, borrow someone elses cylinder, it really does work! WARNING: If you have an after-market aluminium cylinder, please be aware that it is not recommended that you fill it quickly due to safety reasons.
This video shows how to fix an air leak down the barrel by polishing the exhaust valve housing insert and then re-seating the exhaust valve to the newly polished cover.
You have most likely smashed the sears. If you have undertaken any work to the gun, ie. replaced the anti tamper, when re-assembling you MUST make sure that the trigger unit is NOT in a cocked state (press the trigger before attaching to the gun). If you fit the trigger section to the gun when it is cocked you WILL smash the trigger sears - usually the middle sear.
How do you know if you have smashed the sears? On cocking the gun, when you push the cocking lever forward, the gun automatically fires itself (this is because the sear adges are smashed and there is nothing for it to "latch" to).
Weihrauch recommend that you use "Divers air quality only" to fill your air cylinder - this is because it has a VERY small moisture content - you can only get this quality air from a dive bottle. Most pumps can only guarantee to provide air that is 90% moisture free - even with a dry pack filter attached.
Any time that you fill your cylinder from empty, remove it from the gun to fill with air 150 to 200bar, then screw it back onto your gun. This is so that the exhaust valve gets a good shot of air to create the best seal. You should do this anytime that your air cylinder has completely emptied to avoid leaks…
NEVER put WD40 on your gun!
Only special lubricants specifically designed for pcp-air guns should be used. These are sophisticated oils specially formulated for this purpose. Of the hundreds of oils available, only a few have the proper viscosity, lubricity, lack of acids for use in fine quality pcp-air guns. Our workshop recommend Molykote 33M or our own Professional Airgun Lube.
Never oil the connecting threads and valves of your rifle’s air cylinder and always protect the thread and inlet valve with the dust cover cap provided. That goes for the original Weihrauch cylinder AND our Titanium Cylinders.
In short - you have probably tightened the two parts of the brass valve together too hard. It is a bit fiddly - it needs to be tight enough that the two parts do not come apart when you screw/unscrew the air cylinder in & out of the block, but not so tight that it causes the oring inside the valve to bulge. If you need to, use a small amount of blue (medium) thread-locker.
The brass valve where the air cylinder is connected directly into the gun block is not actually the main valve for the air access from the cylinder as many believe - that is inside the actual air cylinder. The nipple on the brass valve that you can see in the block simply pushes open the valve inside the air cylinder when the cylinder is screwed on. The brass valve is actually the Regulator Valve and when working properly on a HW100, should fill more or less instantly. The valve can be rebuilt but it is a lot more difficult than people expect....
The brass Regulator Valve is in two parts with an o-ring, ball bearing and spring in between them. This o-ring (in conjunction with the ball bearing) is the valve for the regulator AND the seal for the two brass parts. See ipctures below.
Most people tighten these two parts of the valve together as hard as they can. Tightening too hard can cause the internal o-ring to bulge (inwards) and slightly grip the piston pin of the regulator. This causes slow filling and fluctuations in the firing cycle.
Weihrauch are presumably aware of this problem - the newer HW100's (like the HW100BP) now have a slightly different piston with a fluted pin with grooves in it to allow air through to the regulator (see 3rd picture below). Unfortunately, you can't buy these pistons yet, we are just seeing them in the newer models coming from Weihrauch!
But why would slow filling cause a problem? The plenum on the HW100 is very small and as such cannot supply enough air to fire a full shot on it's own. So when every shot is taken, some air is actually dragged through the regulator direct from the tube... but if you have a slow filling regulator, then the air flow is restricted.
Our Brass Valve Service Kit supplies everything you need to re-build and service the brass Regulator Valve on your HW100 without having to buy the whole brass valve - saving you £££'s! We supply original Weihrauch specification seals (black) AND upgraded polyurethane seals (red) - you can use whichever ones you prefer.
On the back of the tin of JSB pellets you will find a sticker with three sets of numbers (JSB Exact Jumbo Cal .22 pictured):
1st Number: 15050017
2nd Number: 1
3rd Number: 5.52
The 1st number is broken down into the following:
When buying pellets, look at the last 2 digits for the year of production - try and get the newest pellets you can - JSB had a "bad batch" in approx 2015 where the domes on the pellets were not as full as they should be and gave very poor results.
The 2nd number (1) is the manufacturing batch number.
The 3rd number is the calibre head size 5.52.
We understand that it can be frustrating when your beloved air rifle isn't working as it should - whether you need it for work or for play. We spend a lot of time offering free support - and are happy to do so - but if you want to send us £1 (or whatever, it's entirely up to you) to say "thankyou" we are always most grateful...