Help & Advice From our Service Engineers

Get yourself a chronograph.  Anyone with an air weapon should own or have access to a chronograph and regularly test the power output to ensure that the gun is within legal limits (if your country HAS legal limits).  It can also tell you if your gun is UNDER powered and needs a service, repair or just a barrel clean! ("Leading up" a barrel does not apply to PCPs - clean your barrel, you may find that the power goes up by half ft lb!) 

We are seeing a lot of air cylinders coming to us for service because users are not putting lubricant on their fill probe & dust plug when they are filling their air cylinder.  Dry bits of rubber are shearing off the probe & getting blown into the fill valve - debris in the fill valve will cause a slow or fast leak & can also stop you from filling the cylinder with air eventually.   If you look in the Weihrauch User Manual, it will tell you never to oil your threads, valves or charging equipment for the air cylinder as there is a danger of explosion.   This is because a lot of people don't realise that you can't just put ANY old oil or grease on your PCP - it has to be a VERY specific type of oil/grease - it has to be inert (chemically inactive) & therefore not dangerous to use on the fill probe.   ALL rubber oring seals work better with a little bit of grease/oil on them - including the fill probe! See below for which oils/grease are safe.  PLEASE, make sure your fill probe & dust plug are clean.  Any bits of muck on your fill probe/dust plug are going to get blown into your fill valve.

NEVER put WD40 on your gun!  

Only special lubricants/oil/grease 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  - it is perfectly inert (chemically inactive) silicone based and perfectly safe to use on your PCP - even on the fill probe seals.

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.  ALWAYS lube your fill probe with a silicone based oil/grease - otherwise dry bits of rubber from your probe can shear off and get caught in your fill valve as mentioned above. 

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 Hills type pumps can only  guarantee to provide air that is 90% moisture free - even with a dry  pack filter attached. The picture here shows the fill valve from an air cylinder we serviced recently which has been damaged by prolonged exposure to moisture from using an air pump - we can't say whether the pump is damaged or how long it took for this damage to occur, but if you can, we would always recommend that you use a dive bottle.  The damage on this particular fill valve pictured included the spring, seal and the valve housing - they were all covered in limescale/calcium from the excess moisture - the cylinder was leaking because the seal & housing was damaged and didn't have a flat surface to seal against due to the limescale build up.

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…

If it's a HW100, 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.  
If it's a HW110, the sears are probably worn, they are not a great design on the HW110, they tend to wear out faster on the HW110 compared to the HW100.

How do you know if you have damaged 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). 

The easiest way to determine whether it's your gun OR theWeihrauch air cylinder that is leaking on your HW100 is to take the air cylinder off the gun, put some air into it, pop a balloon over each end of the cylinder, making sure that you cover the fill port and the gap where the end cap is screwed onto the tube (see picture).  Check that the balloons do not have any tiny holes in them, leave it for a few hours and if either of the balloons inflate, you know that it's your air cylinder that is leaking, and you also know which end is leaking!  If it doesn't inflate - you have a leak on your gun.  The first seal to replace is the 2665d - the one that you can see inside the block where you screw your cylinder in.  Be careful taking the old seal off - don't scratch the brass valve! If it's still leaking after that, try a full service seal kit - or send it to us! 

The 2665D seal (the little seal you can see sitting on the brass valve inside the block when you unscrew the air cylinder) is considered a consummable on the HW100 - this is usually the first seal that needs replacing, particularly if you are taking the air cylinder on and off the gun.  PLEASE be very careful when removing the old seal from the brass valve - more often than not, we see scratches/gouges on the sealing face of the valve when guns come to us for service because someone has used something sharp/metal to remove the old seal.  Once you scratch this surface, you will most likely find that the gun develops a slow leak - it only has to be a small scratch, but 200bar will find a way to get through it! CLICK HERE to buy replacement seals for your HW100.

You've got a leak on your Weihrauch HW100, it's coming from a small hole under the block, you are replacing the seals around the regulator and you come across this hard, plastic washer/ring.  It's not on the schematic/exploded washer, you have looked for a replacement part and it's not in the service kit... what is it, what's the part number, where can I get one from?   It's not a washer!  It might look & feel like a brittle, plastic washer, but once upon a time, that "washer" was a rubber oring.   Over time, the orings get compressed as they are under pressure and they become hard and brittle - and that's when they start leaking as there is no "squidge" left in the rubber.   Remove the old seal - be careful not to scratch anything when removing the old seal, they can be stuck in place quite hard.  Replace with seal number 2674B - Inlet Valve B. 

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:

• 15 = The number of the pressing die that was used to make the pellets.
• 05 = Production Employee ID.
• 00 = Quality Control Employee ID.
• 17 = Year of production.

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.