Hatsan AT44 QES PCP Air Rifle Impressions

[Whirligig]

I usually do a write up of my new airguns, but I'm going to wait until I learn more about the PCP world before I consider myself to have enough knowledge or experience for a review of the Hatsan AT44 QES PCP Air Rifle.

But, overall, I really like the airgun, but hate the fill probes. It seems to be the luck of the draw which fill probe will work, and the rubber o-rings get shredded almost immediately. So, gun good; fill probes bad. That's my review at this point in time.

I haven't had any leaks other than those caused by fill probes, but I found the video below, and am posting it here in case I need to watch it again, or if anyone else finds it useful.



If anyone wants to share their knowledge about PCP airguns, fill probes, and/or the Hatsan AT44 QES PCP Air Rifle, specifically, I would love to read about your experiences.

Thanks!

-W

[redlined_b16a]

I remember leaving my fill probe in.......when it wasn't leaking lol.
I bought some 90 durometer ones and they lasted longer.
Silicone oil on the rings help.

The issue is the port is a sharp machined edge.
A simple bevel would have been great and solved this issue.

My old AT44s-10 has seen over 20k rounds and has been the most reliable gun I ever owned.

[Whirligig]

I remember leaving my fill probe in.......when it wasn't leaking lol.
I bought some 90 durometer ones and they lasted longer.
Silicone oil on the rings help.

The issue is the port is a sharp machined edge.
A simple bevel would have been great and solved this issue.

My old AT44s-10 has seen over 20k rounds and has been the most reliable gun I ever owned.

I just ordered 20 90 durometer silicone o-rings and will see if I have the same experience that you did.

Yes, those ports' edges are razor-sharp.

I'm reassured by your experience with the AT44.

Thanks!

-W

[avator]

Can you use a Dremel and a fine conical stone to relieve that edge a bit? Shouldn't need to be as precise as the crown on a barrel. Just enough to keep the sharp edge off the oring.

[mikeyb]

I've been using the stainless steel aftermarket fill probes (~$10 Amazon) on all my Hatsan PCPs and Vortex air springs for several years. Have not had any o-ring failure yet.

ONE cheap ($8) fill probe from Banggood blew out the o-rings on first use. I replaced those "cheap, too soft, old?" o-rings with 90A NEW ones and that probe has worked fine. Drop of silicone oil or a smear of silicone grease helps. If it doesn't go in smooth the probe alignment is off.

[Whirligig]

Can you use a Dremel and a fine conical stone to relieve that edge a bit? Shouldn't need to be as precise as the crown on a barrel. Just enough to keep the sharp edge off the oring.

I was wondering this exact thing. I'll give it a try, but very carefully.

Thanks,

-W

[HectorMedina]

In my experience, the problem is not the hardness of the rings, but the size.
I changed mine for smaller rings (M6X1.5, which means 6 mm's ID, 1.5 mm's CS) and it works like a charm.

I do not OWN a Hatsan AT 44, but recently worked extensively with a Hämmerli Pneuma that is the same beastie.

They seem to be loose,



but remember the ORings seal by MOVING and partially extruding themselves into the hollows created by the gland to shaft to bore clearances.

So, save yourself headaches and use smaller ORings. They will move and expand with the pressure, sealing well, and when the hose is emptied, they will return to their size and allow an easy removal from the bore. Insertion is also ridiculously easy. Just a touch of "Superlube" on them and they will work forever.

I found the action to be severely oversprung, so if you want more efficiency from it, an Altaros regulator and a mod may be what is needed.

If you want to read in depth, it is here:  https://www.ctcustomairguns.com/hectors-airgun-blog/the-hammerli-pneuma

HTH, keep well and shoot straight!





HM

[Blowpipe Sam]

Can you use a Dremel and a fine conical stone to relieve that edge a bit? Shouldn't need to be as precise as the crown on a barrel. Just enough to keep the sharp edge off the oring.

I was wondering this exact thing. I'll give it a try, but very carefully.

Thanks,

-W

Before I'd use a stone I'd try a bit of fine steel wool wrapped around the end of a pencil.  That should be enough to round the edge off.  Remember Hatsan uses fairly soft steel.

[Whirligig]

Can you use a Dremel and a fine conical stone to relieve that edge a bit? Shouldn't need to be as precise as the crown on a barrel. Just enough to keep the sharp edge off the oring.

I was wondering this exact thing. I'll give it a try, but very carefully.

Thanks,

-W

Before I'd use a stone I'd try a bit of fine steel wool wrapped around the end of a pencil.  That should be enough to round the edge off.  Remember Hatsan uses fairly soft steel.

Brilliant!

I'll try that first!

-W

[avator]

Before I did anything I would make sure I put some kind of plug in the probe port and cleaned it out real good when done. Wouldn't want to get anything down inside the gun.

[Whirligig]

Before I did anything I would make sure I put some kind of plug in the probe port and cleaned it out real good when done. Wouldn't want to get anything down inside the gun.

I was careful not to get anything into the gun. Afterwards, I cleaned out the probe port with some electrical contact cleaner, which leaves no residue and then added a little silicone oil to coat the clean metal.

-W

[avator]

Before I did anything I would make sure I put some kind of plug in the probe port and cleaned it out real good when done. Wouldn't want to get anything down inside the gun.

I was careful not to get anything into the gun. Afterwards, I cleaned out the probe port with some electrical contact cleaner, which leaves no residue and then added a little silicone oil to coat the clean metal.

-W

Good job... didn't doubt you for a second.. 

[Whirligig]

In my experience, the problem is not the hardness of the rings, but the size.
I changed mine for smaller rings (M6X1.5, which means 6 mm's ID, 1.5 mm's CS) and it works like a charm.

I do not OWN a Hatsan AT 44, but recently worked extensively with a Hämmerli Pneuma that is the same beastie.

They seem to be loose,



but remember the ORings seal by MOVING and partially extruding themselves into the hollows created by the gland to shaft to bore clearances.

So, save yourself headaches and use smaller ORings. They will move and expand with the pressure, sealing well, and when the hose is emptied, they will return to their size and allow an easy removal from the bore. Insertion is also ridiculously easy. Just a touch of "Superlube" on them and they will work forever.

I found the action to be severely oversprung, so if you want more efficiency from it, an Altaros regulator and a mod may be what is needed.

If you want to read in depth, it is here:  https://www.ctcustomairguns.com/hectors-airgun-blog/the-hammerli-pneuma

HTH, keep well and shoot straight!

HM

A combination of polishing the port edges with steel wool AND using smaller o-rings did the trick on a AT44 that just did not want to take a fill and was shredding every slightly-larger o-ring that came with the aftermarket fill probes that I used!

Thanks!

-W

[Back_Roads]

 I found I had to swap to smaller orings for a couple of guns I set up with the bargain probes, others were perfect as is.

[Whirligig]

I found I had to swap to smaller orings for a couple of guns I set up with the bargain probes, others were perfect as is.

The odd thing is that the original factory probes that came with the gun don't work with the original factory o-rings, but the aftermarket probes with the original factory o-rings, and not the larger o-rings that were provided with the aftermarket probes, are what worked for me (on this particular Hatsan AT44 QES). I've ordered more of the smaller o-rings from Amazon.

The original fill probes for the Umarex Iconix fit absolutely perfectly every time and "snap" into place, and are extremely easy to insert and remove. However, I can't find aftermarket probes (not that I need them) for the Iconix. Even Umarex doesn't sell them, or even know what the dimensions are.

This PCP thing is a whole new world...

-W

[HatsanPhantom]

How do you guys clean your AT44 qes? I got mine in December but haven’t cleaned it yet.

[naptemp]

These are the Foster fill probes I used on my Hatsan AT44 and Kral NP-03:
https://www.aliexpress.us/item/3256804967162981.html
Item selected: For Hatsan-9MM(QD)

They work really well.

[mikeyb]

How do you guys clean your AT44 qes? I got mine in December but haven’t cleaned it yet.

I remove and disassemble the barrel/shroud/QE parts to clean the bore just after receiving the rifles.

Cleaning the bore is easy when you get down to the bare barrel.

I do this because Hatsan has poor QC and barrels can be very dirty or "bad".

After cleaning I push a few pellets to check bore fit. Haven't had a bad "free fall" barrel yet. However I've had some QES rifles with sliced barrel o-rings from rushed factory assembly. Also had some bad muzzle crowns. You can't find and fix these without disassembly.

So far I've replaced sliced o-rings and successfully recrowned all my QES. I've also reduced the hammer force to get a velocity that is useful to me over several magazines.

I usually clean an airgun bore only one time when I receive the rifle (new, refurb, and used). If an air rifles accuracy starts to decline after several thousand shots I'd try cleaning the bore again, but I'm not there yet.

[HatsanPhantom]

Thank you for this information. I’m a little hesitant to take the barrel off but I think it’s time to clean the bore. I was having good results as far as accuracy and then I wasn’t.

[naptemp]

I have 2 AT44 (short .22, long .177) bought last year when PyramidAir had them for $150 plus some additional coupons.

I have been struggling to get longer shot strings.
To flatten the shot string I have used a buffer between the hammer and valve face (similar to BStaley).

Has anybody tried to get a longer flatter shot string?
If yes, how did you do it?

These are my current tunes.

Hatsan AT44 .177 long
Pellet: Norma domed 9.1 grains
Pressure: 240 bar to 180 bar
Velocity: 845-883 FPS
Shots: 40-50 shots

Mods
Valve hammer buffer (AKA BStaley): Height around 1.98-2.02mm, OD 14.1mm, ID 6mm

Hatsan AT44 .22

** 2025-02-13

Pellet: CPHP 14.3 grains
Pressure: 255 bar to 180 bar
Velocity: 780-813 FPS
Shots: 40 shots (4 mags)

Mods
Valve hammer buffer (AKA BStaley): Height 2.25mm, OD 14.1mm, ID 6mm