Hatsan AT44 QES PCP Air Rifle Impressions

[HectorMedina]

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.

Depending on caliber, I mke my own "Crown Savers"
Take a rigid plastic tube that is JUST under your bore size (4 mm's for 0.177" and 5 mm's for 0.22"), then get trimmer line that is 1 mm thick.
Create a loop and insert it into the plastic tube so that you have an "eyelet" once you push it through the barrel from the muzzle to the mag.
Tie the two halve together and cap it at the other end with a small wooden dowel
When the loop / "eyelet" appears, roll a piece of flannel/cleaning patch so that when it bends in half it is thick enough to clean the grooves.
Now pull on the dowel and the rolled patch will come to you through the barrel and will not get held by the Mod.

It is my favourite way to clean all bullpups.

;-)

Keep well and shoot straight!




HM

[HectorMedina]

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

John, your best bet is to add a regulator. The BEST regulators are by Altaros:

https://www.altaros.cz/domu/18-4753-hatsan-at44-hammerli-pneuma-elite-bullboss.html#/25-caliber-177_45mm/40-required_energy_with_regulator-75j_55_ft_lbs

After that, reducing the transfer port is the best way to "flatten" the inverted bath-tub curve, but you will need a series of numbered drills because VERY SMALL difference in the diameter of the TP will have appreciable difference in the MV.

HTH, keep well and shoot straight!





HM

[mikeyb]

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?
...

AT44 Short 180cc, 255 BAR ~ 3700 psi, 180 BAR ~2610 PSI
AT44 Long 230cc, 240 BAR ~ 3480 psi, 180 BAR ~2610 PSI

Interesting. Do you over-pressure all your PCP rifles?
I sincerely hope that never causes a problem for you.


I shoot all my Hatsan PCP (at44 & bt65 series) rifles from-to  3000psi (207 BAR) - 2000psi (138 BAR)

Hatsan rates their tubes "200 BAR max" (2900 psi) so I choose to poke that bear only a little bit. I can tell from my hammer adjustments and shots curves that if I filled to something like 3400psi the rifle would experience valve-lock.

I'm getting 4-6 mags "usable to me" shots with only the hammer spring dialed low within the normal adjustment range. Shot strings are unregulated and are the inverted bathtub curves. First couple pellets with rising MV, several mags within a +/-4% envelope, then a couple final pellets just outside the 4% window as the pressure gets down to ~2000 psi. That may be "too loose" for some but it works for me.

No BStaley mods but I've considered trying that on the 177s to get another mag or two per fill after lowering the velocity a little more.  There is a long detailed GTA thread about getting the maximum efficiency and shot count by plugging some of the excess valve holes and optimizing the air path to the pellet. Very interesting stuff. For now I like my 177 right where it is and I'm done tinkering.

I have a used/refurbished Galatian (bt65 tube 255cc) that has the Hammer spring dialed LOWER than normal because I've removed a small 1/4" spacer than normally stays in with the hammer spring. I'm very happy with that rifle right where it is now so no further tinkering on that one.

None of my rifles are shooting anywhere near their peak energy potential.  It is nice to have the option of dialing in more ME but currently I simply don't need them tuned there.

IMO you are already "dialed in" unregulated at those pressures. Hector's suggestion of going regulated seems like your best option.

[naptemp]

I am slightly overfilling some of my airguns, those unregulated and with a poor valve design.

Also, the gauge on both AT44 show about 30 bar more than the gauge on my compressor.
And I trust my compressor since its gaige mostly matches several other PCPs' gauges.

My Beeman Raiders, also unregulated and with a smaller air tube give me longer flatter shot strings after adding a BStaley buffer.

The Hatsan AT44 design and performance is PRIMITIVE by today's standards.