New Hatsan PCP AirGun Fill Probe Parts – O-rings and Caps

I have two Hatsan precharged pneumatic (PCP) airguns – a full size Gladius .22 long and a compact ATP2. I recently needed to replace the O-rings and started researching what was needed.

The O-Rings

Here’s a Hatsan probe and the brownish/tan O-rings are their OEM rings. The black rings are the Buna-N rubber rings that we are now selling.

My two Hatsan’s get pressurized up to 300 bar, which is 4,351 PSI. That’s quite a bit of pressure that the fill probe’s O-rings need to contain plus they need to be flexible enough to allow for insertion and a good seal. One last consideration is the need to withstand the silicone grease that is used to lubricate them (never use oil-based grease on a PCP or it may diesel under pressure).

The O-rings are wear items meaning they will wear out for a variety of reasons and you can tell because when you go to fill the airgun’s tank, you will hear air escaping plus you probably will not be able to get very much pressure to stay in the line. So when mine went out and I installed the spare set that came with the Gladius, I had to think about getting more spares. Hatsan was out of stock at the time so I decided to dig.

So, I started researching what O-rings would work best and sourced some that work great. They are 70A on the shore hardness scale and made from Buna-N rubber which will withstand the silicone grease.

In addition to fitting Hatsan PCP fill probes, they will also fit the Air Venturi Halestorm, Evanix, FX, Hammerli Pneuma, Kral, Lgun and Raider probes.

Click here for the product page on our website to see pricing and place an order.

Keeping the Probe Clean – Caps

While I was at it, I decided to tackle how to keep the probe clean. I’ve had my Hatsans and my Hill Mk4 air pump for a couple of years and have tried to keep bags on the probe to keep it clean. Those semi-rigid airlines flop everywhere and trying to keep dirt off the probe that is sticky with silicone grease is a challenge.

Here’s the uncovered probe begging to have dirt and debris stick to it.

So, after measuring stuff. I came up with two types of caps for people to choose from. The first is a yellow cap with a pull tab.

Here’s the yellow pull tab cap that extends just past the rear O-ring

These are for folks who want to protect their probe but want a bright color that is easier to find. Click here for the product page to read the measurements, see the pricing and order.

The second cap I came up with is a longer black cap that covers the whole probe. It’s basic black but it does protect the whole probe and is what I am personally using now.

This literally is my cap on my Hatsan fill probe. It’s what I now use to keep to clean and it comes on and off real easy!

To learn more about the measure, pricing and to order, please click here.


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