• Jefferson State Airrifles
  • Air Gun Web - Expert Airgun Reviews
  • Hajimoto Productions
  • Airgun Angie - Backyard Shooting
  • Nielsen Specialty Ammo
  • Dynamic Air Rifles
  • FX Airguns
  • DonnyFL - When silence is a priority
  • Airgun Archery Fun
  • Pyramyd Air
  • Saber Tactical
  • New England Airgun
  • Umarex Airguns
  • Contact us
  • Utah Airguns
  • SEKHMET Airgun Accessories
  • Freedom Gun Targets
Jefferson State Airrifles
Air Gun Web - Expert Airgun Reviews
Hajimoto Productions
Airgun Angie - Backyard Shooting
Nielsen Specialty Ammo
Dynamic Air Rifles
FX Airguns
DonnyFL - When silence is a priority
Airgun Archery Fun
Pyramyd Air
Saber Tactical
New England Airgun
Umarex Airguns
Contact us
Utah Airguns
SEKHMET Airgun Accessories
Freedom Gun Targets


Author Topic: AT44 + reg = stumped!  (Read 497 times))

Online GoneShootn

  • Marksman
  • ***
  • Posts: 496
  • yes
  • Real Name: Jere
AT44 + reg = stumped!
« on: May 03, 2021, 10:02:07 PM »
It's been a long time since I fooled around with my Hatsan AT44 .177, so I got it out the other day and decided to finally tune it with the new Audrius reg in. I had seen Bob Sterne's scholarly treatise on the subject and then watched the Brothers in Air YT video as a refresher. The idea was to increase the hammer spring to the FPS plateau and then back off a bit. If final velocity is not where I want it, then adjust the reg and repeat. Worked like a charm with my Marauder .25 which is now stacking pellets at 35 yds. Velocity only at about 815 FPS, but I can live with 37 FPE and pellets going where I aim.

So on to the AT44. Same procedure, only adjusting the HS has no effect at all. I have tried reg settings to give strings of around 825 FPS and then one to give around 900 FPS plus one in between, all at HS=0. Each time, however, when I advanced the HS outward, or upward, there was little, if any, change. I'm thinking maybe the valve spring is broke,, but I checked and it isn't. Another thing that is happening, which may be unrelated, is that every 5 shots or so I get one that is 70 FPS lower than the average of the others.

As I said, it's been a while since I've been down this road, so I may have forgotten something important. Strike that. I have probably forgotten something important. Any suggestions will be appreciated.
« Last Edit: May 03, 2021, 10:13:59 PM by GoneShootn »
  • Barnesville, Georgia
Benjamin Marauder .25, Gen 2, Hawke Sidewinder 6-24x56
Hatsan AT44 Long .25, synthetic stock, tuned by BWalton, Hawke Airmax 4-16x50
Hatsan AT44 Short .177, synthetic stock, Centerpoint 4-16x40
Hatsan AT44 Tactical QE .22, Hawke Vantage 4-12x40
LDC aka moderator aka suppressor by BWalton, used for both non-QE Hatsans
ShoeboxMax compressor
California Air Tools 5510SE booster compressor
Ninja 90 cu in carbon fiber bottle
Hill MK3 pump
MRodAir (Huben) pump

Online Back_Roads

  • I Got A 10 Pump BB Gun :) BB Guns Got Much More Complicated :)
  • GTA Senior Contributor
  • ******
  • Posts: 7846
  • 1st Edition Crosman 760 Pump Master
    • Back_Roads Airgunning
  • Real Name: James Seiler
Re: AT44 + reg = stumped!
« Reply #1 on: May 03, 2021, 10:34:49 PM »
 Might be something like a breach oring going bad, or hammer drag, etc, best to dig into it may be simple, may take all of our brains  :-\
  • Wisconsin Collins ;Hunters Paradise; Theres a Sign in town to prove it :)
(Sorry, but you are not allowed to access the gallery)

https://www.youtube.com/channel/UC3hMPAjvTtuu7DoNzBZzuKQ?view_as=subscriber
 Below is a collection of helpful airgun videos
https://www.youtube.com/playlist?list=PLASJo4rBxMImx-kNnbppkIBV86G5Yentf

Online GoneShootn

  • Marksman
  • ***
  • Posts: 496
  • yes
  • Real Name: Jere
Re: AT44 + reg = stumped!
« Reply #2 on: May 03, 2021, 10:47:09 PM »
Might be something like a breach oring going bad, or hammer drag, etc, best to dig into it may be simple, may take all of our brains  :-\

I guess I'm going to have to put on my mechanic's hat and roll my sleeves up. We'll see what we see. :)

Thanks.
  • Barnesville, Georgia
Benjamin Marauder .25, Gen 2, Hawke Sidewinder 6-24x56
Hatsan AT44 Long .25, synthetic stock, tuned by BWalton, Hawke Airmax 4-16x50
Hatsan AT44 Short .177, synthetic stock, Centerpoint 4-16x40
Hatsan AT44 Tactical QE .22, Hawke Vantage 4-12x40
LDC aka moderator aka suppressor by BWalton, used for both non-QE Hatsans
ShoeboxMax compressor
California Air Tools 5510SE booster compressor
Ninja 90 cu in carbon fiber bottle
Hill MK3 pump
MRodAir (Huben) pump

Offline elguapo99

  • Plinker
  • **
  • Posts: 224
  • yes
  • Real Name: Robert
Re: AT44 + reg = stumped!
« Reply #3 on: May 03, 2021, 11:50:48 PM »
You may already know this but when adjusting the hammer spring, make sure that the hammer is not rotating by inserting a punch in the hole to keep the hammer from turning. The hammer spring will not adjust if the entire mechanism turns.
Here's an explanation by rsterne: http://www.canadianairguns.com/showthread.php?656-Hatsan-25-cal-AT44S-10-Long-Mods
  • Loudon, TN
Crosman 2100 Classic .177 Tuned
Crosman Storm XT .177 Tuned
Walther LGU Varmint .22 Tuned
Air Venturi Avenger .22
Hatsan AT44S-10QE .22
Kral Puncher Breaker Silent Marine .22
Benjamin Marauder Pistol (PRod) .22 Huma Reg'd
SPA PP700S-A .22 & .177 barrels
Yong Heng Compressor
(3) 30 min. SCBA Tanks
You can tune an airgun but you can't tune-a-fish.

Offline Pelletjunkie

  • Sharp Shooter
  • ****
  • Posts: 987
  • yes
  • Real Name: Frank
Re: AT44 + reg = stumped!
« Reply #4 on: May 04, 2021, 12:48:48 PM »
I’m not a Hatsan guy so I don’t know if the At44 came from the factory with a reg. If it didn’t, you have some porting to do.
  • United States, Pa, Mineral Point

Online GoneShootn

  • Marksman
  • ***
  • Posts: 496
  • yes
  • Real Name: Jere
Re: AT44 + reg = stumped!
« Reply #5 on: May 04, 2021, 01:44:43 PM »
You may already know this but when adjusting the hammer spring, make sure that the hammer is not rotating by inserting a punch in the hole to keep the hammer from turning. The hammer spring will not adjust if the entire mechanism turns.
Here's an explanation by rsterne: http://www.canadianairguns.com/showthread.php?656-Hatsan-25-cal-AT44S-10-Long-Mods

Good suggestion. Doesn't seem to be the problem. I have drilled a hole to allow external access. Wish it was. Thanks.
  • Barnesville, Georgia
Benjamin Marauder .25, Gen 2, Hawke Sidewinder 6-24x56
Hatsan AT44 Long .25, synthetic stock, tuned by BWalton, Hawke Airmax 4-16x50
Hatsan AT44 Short .177, synthetic stock, Centerpoint 4-16x40
Hatsan AT44 Tactical QE .22, Hawke Vantage 4-12x40
LDC aka moderator aka suppressor by BWalton, used for both non-QE Hatsans
ShoeboxMax compressor
California Air Tools 5510SE booster compressor
Ninja 90 cu in carbon fiber bottle
Hill MK3 pump
MRodAir (Huben) pump

Online GoneShootn

  • Marksman
  • ***
  • Posts: 496
  • yes
  • Real Name: Jere
Re: AT44 + reg = stumped!
« Reply #6 on: May 04, 2021, 01:46:48 PM »
I’m not a Hatsan guy so I don’t know if the At44 came from the factory with a reg. If it didn’t, you have some porting to do.

It didn't. Anyway, I wouldn't think that adding a reg would make the HS adjustment totally useless, but what do I know? ;)
  • Barnesville, Georgia
Benjamin Marauder .25, Gen 2, Hawke Sidewinder 6-24x56
Hatsan AT44 Long .25, synthetic stock, tuned by BWalton, Hawke Airmax 4-16x50
Hatsan AT44 Short .177, synthetic stock, Centerpoint 4-16x40
Hatsan AT44 Tactical QE .22, Hawke Vantage 4-12x40
LDC aka moderator aka suppressor by BWalton, used for both non-QE Hatsans
ShoeboxMax compressor
California Air Tools 5510SE booster compressor
Ninja 90 cu in carbon fiber bottle
Hill MK3 pump
MRodAir (Huben) pump

Offline Tucobenedicto

  • pest sniper
  • Sharp Shooter
  • ****
  • Posts: 860
  • yes
  • Real Name: Fabio
Re: AT44 + reg = stumped!
« Reply #7 on: May 04, 2021, 02:20:25 PM »
If you don't see a speed drop even at the minimum hammer spring preload, maybe is time to switch to a softer hammer spring or cut some coil from the spring. Can happen if the regulated pressure is considerably lower respect to the original fill pressure.
  • Perugia middle Italy
Hammerli 850 PCP .177
Bottled regulated Prod .22 16,5" Barrell

Offline Ribbonstone

  • GTA Senior Contributor
  • ******
  • Posts: 10456
Re: AT44 + reg = stumped!
« Reply #8 on: May 04, 2021, 02:20:44 PM »
Just a couple of questions….not having used that regulator...and stuff you already know.

But sometimes we get kind of narrow focused.

Assuming there is no mechanical problem and everything is working normally.

1. Does it reduce velocity if you back the spring tension way off.  Would not make for the speed you want, but if it then acts like you’d expect a regulator to act, at least know it works. 

By testing, could get a ball park idea of what the real world output pressure.

2. Plenum size?

I expect that at a certain point, more spring tension doesn’t give significant velocity change...basically ran out of pre-regulated air.  May not be able to easily change the plenum.
  • Louisiana

Online GoneShootn

  • Marksman
  • ***
  • Posts: 496
  • yes
  • Real Name: Jere
Re: AT44 + reg = stumped!
« Reply #9 on: May 04, 2021, 02:27:22 PM »
If you don't see a speed drop even at the minimum hammer spring preload, maybe is time to switch to a softer hammer spring or cut some coil from the spring. Can happen if the regulated pressure is considerably lower respect to the original fill pressure.

Makes a lot of sense. Thanks.
  • Barnesville, Georgia
Benjamin Marauder .25, Gen 2, Hawke Sidewinder 6-24x56
Hatsan AT44 Long .25, synthetic stock, tuned by BWalton, Hawke Airmax 4-16x50
Hatsan AT44 Short .177, synthetic stock, Centerpoint 4-16x40
Hatsan AT44 Tactical QE .22, Hawke Vantage 4-12x40
LDC aka moderator aka suppressor by BWalton, used for both non-QE Hatsans
ShoeboxMax compressor
California Air Tools 5510SE booster compressor
Ninja 90 cu in carbon fiber bottle
Hill MK3 pump
MRodAir (Huben) pump

Online GoneShootn

  • Marksman
  • ***
  • Posts: 496
  • yes
  • Real Name: Jere
Re: AT44 + reg = stumped!
« Reply #10 on: May 04, 2021, 02:31:08 PM »
Just a couple of questions….not having used that regulator...and stuff you already know.

But sometimes we get kind of narrow focused.

Assuming there is no mechanical problem and everything is working normally.

1. Does it reduce velocity if you back the spring tension way off.  Would not make for the speed you want, but if it then acts like you’d expect a regulator to act, at least know it works. 

By testing, could get a ball park idea of what the real world output pressure.

2. Plenum size?

I expect that at a certain point, more spring tension doesn’t give significant velocity change...basically ran out of pre-regulated air.  May not be able to easily change the plenum.

Will have to shoot it down to get idea of true reg pressure, but I'm guessing now sitting at 100 to 110 bar. And will have to look up the reg specs. So I'll have to get back to you. Thanks.
  • Barnesville, Georgia
Benjamin Marauder .25, Gen 2, Hawke Sidewinder 6-24x56
Hatsan AT44 Long .25, synthetic stock, tuned by BWalton, Hawke Airmax 4-16x50
Hatsan AT44 Short .177, synthetic stock, Centerpoint 4-16x40
Hatsan AT44 Tactical QE .22, Hawke Vantage 4-12x40
LDC aka moderator aka suppressor by BWalton, used for both non-QE Hatsans
ShoeboxMax compressor
California Air Tools 5510SE booster compressor
Ninja 90 cu in carbon fiber bottle
Hill MK3 pump
MRodAir (Huben) pump

Online GoneShootn

  • Marksman
  • ***
  • Posts: 496
  • yes
  • Real Name: Jere
Re: AT44 + reg = stumped!
« Reply #11 on: May 04, 2021, 03:32:39 PM »
Installed the 2nd, unregulated, cylinder and filled to 200 bar. This thing is a beast! I had forgotten how gnarly it was. With all 6 ports open and HS at 0 (assuming mechanically ok), FPS is well over 1000 with JSB 13.43gr pellets. With 3 holes plugged, it is still over 1000 FPS. Going down to 1 hole.
  • Barnesville, Georgia
Benjamin Marauder .25, Gen 2, Hawke Sidewinder 6-24x56
Hatsan AT44 Long .25, synthetic stock, tuned by BWalton, Hawke Airmax 4-16x50
Hatsan AT44 Short .177, synthetic stock, Centerpoint 4-16x40
Hatsan AT44 Tactical QE .22, Hawke Vantage 4-12x40
LDC aka moderator aka suppressor by BWalton, used for both non-QE Hatsans
ShoeboxMax compressor
California Air Tools 5510SE booster compressor
Ninja 90 cu in carbon fiber bottle
Hill MK3 pump
MRodAir (Huben) pump

Online GoneShootn

  • Marksman
  • ***
  • Posts: 496
  • yes
  • Real Name: Jere
Re: AT44 + reg = stumped!
« Reply #12 on: May 04, 2021, 05:13:20 PM »
Result with 1 valve hole open below. I'm going to dig out the old unreged tuning info and see what that looks like.

Filled to 170 bar
HS increased from 0 to 5 over string
Finished at 130 bar
1 valve hole open
JSB 13.43 gr pellets

Shot count: 14
Low: 817
Hi: 909
Avg: 881
STD Dev: 27.1
Spread: 92.0

5/4/21 3:39:47 PM,907
5/4/21 3:39:55 PM,907
5/4/21 3:40:52 PM,835
5/4/21 3:41:00 PM,909
5/4/21 3:41:08 PM,905
5/4/21 3:42:05 PM,902
5/4/21 3:42:12 PM,898
5/4/21 3:42:17 PM,884
5/4/21 3:42:25 PM,884
5/4/21 3:43:22 PM,817
5/4/21 3:43:54 PM,879
5/4/21 3:44:00 PM,872
5/4/21 3:44:06 PM,868
5/4/21 3:44:13 PM,863
  • Barnesville, Georgia
Benjamin Marauder .25, Gen 2, Hawke Sidewinder 6-24x56
Hatsan AT44 Long .25, synthetic stock, tuned by BWalton, Hawke Airmax 4-16x50
Hatsan AT44 Short .177, synthetic stock, Centerpoint 4-16x40
Hatsan AT44 Tactical QE .22, Hawke Vantage 4-12x40
LDC aka moderator aka suppressor by BWalton, used for both non-QE Hatsans
ShoeboxMax compressor
California Air Tools 5510SE booster compressor
Ninja 90 cu in carbon fiber bottle
Hill MK3 pump
MRodAir (Huben) pump

Offline Privateer

  • Village Idiot
  • GTA Senior Contributor
  • ******
  • Posts: 6930
  • Air is free until you start compressing it!
  • Real Name: Jeff
Re: AT44 + reg = stumped!
« Reply #13 on: May 04, 2021, 06:13:01 PM »
Never cared for the Hatsan .177's
Out of the box they all seemed to shoot hot.
Opening ports just compounds that issue.
  • Nevada, Ohio
Fleabag Whisperer

Online GoneShootn

  • Marksman
  • ***
  • Posts: 496
  • yes
  • Real Name: Jere
Re: AT44 + reg = stumped!
« Reply #14 on: May 04, 2021, 07:06:31 PM »
Never cared for the Hatsan .177's
Out of the box they all seemed to shoot hot.
Opening ports just compounds that issue.

Not exactly. They come with all 6 ports open, and they are HOT, so 2 things you can do: close off some of the ports and/or (I assume) get a weaker hammer spring. I think this will be a shooter if I can get it right.
  • Barnesville, Georgia
Benjamin Marauder .25, Gen 2, Hawke Sidewinder 6-24x56
Hatsan AT44 Long .25, synthetic stock, tuned by BWalton, Hawke Airmax 4-16x50
Hatsan AT44 Short .177, synthetic stock, Centerpoint 4-16x40
Hatsan AT44 Tactical QE .22, Hawke Vantage 4-12x40
LDC aka moderator aka suppressor by BWalton, used for both non-QE Hatsans
ShoeboxMax compressor
California Air Tools 5510SE booster compressor
Ninja 90 cu in carbon fiber bottle
Hill MK3 pump
MRodAir (Huben) pump

Online Back_Roads

  • I Got A 10 Pump BB Gun :) BB Guns Got Much More Complicated :)
  • GTA Senior Contributor
  • ******
  • Posts: 7846
  • 1st Edition Crosman 760 Pump Master
    • Back_Roads Airgunning
  • Real Name: James Seiler
Re: AT44 + reg = stumped!
« Reply #15 on: May 04, 2021, 07:15:59 PM »
 Dang that is SMOKIN' I have an AT 44 PA short in .177, them are more like the speeds I get with Xman 10.5 gr.  :o Wonder if it would like NSA 13.4 gr slugs, most of my PCP pellet barrels love them.  ???
 Also kept mine unregulated added a Long air tube, barrel extension to attach Fancy LDC past the extended tube, get 4 mags from a 2500 PSI fill, with narrow FPS spread.
  • Wisconsin Collins ;Hunters Paradise; Theres a Sign in town to prove it :)
(Sorry, but you are not allowed to access the gallery)

https://www.youtube.com/channel/UC3hMPAjvTtuu7DoNzBZzuKQ?view_as=subscriber
 Below is a collection of helpful airgun videos
https://www.youtube.com/playlist?list=PLASJo4rBxMImx-kNnbppkIBV86G5Yentf

Offline Texpatriate

  • Shooter
  • *
  • Posts: 78
  • Real Name: John
Re: AT44 + reg = stumped!
« Reply #16 on: May 04, 2021, 07:29:27 PM »
Instructions for the Robt. Lane reg for the at44 say to go with twice the valve spring tension. I have the Huma reg in my .25 cal at44 and that made a difference for me.
  • USA,New York, Amherst

Offline Ribbonstone

  • GTA Senior Contributor
  • ******
  • Posts: 10456
Re: AT44 + reg = stumped!
« Reply #17 on: May 04, 2021, 07:50:00 PM »
Jere:

Yeah...I’d be a bit frustrated as well.  That’s fast, but that’s a whole lot of air being used and it looks a whole lot like an unregulated shot string.

Not real clear to me...you’re increasing string tension as you go along?...or just leaving it alone to see what happens once it runs past reg-set?

Running past reg set might at one spring tension might tell you more.
  • Louisiana

Offline Rallyshark

  • GTA Senior Contributor
  • ******
  • Posts: 3845
  • yes
  • Real Name: Donny
Re: AT44 + reg = stumped!
« Reply #18 on: May 04, 2021, 08:42:18 PM »
Seems to me there's too much hammer spring, and too low of a regulator setting?  Just to clarify, what speed does the gun shoot currently with the regulator installed, and with what weight pellet?  What speed are you wanting it to shoot? There's also a spacer in between the hammer spring and the hammer that can be removed to decrease the tension farther.  Of course, on a AT-44 CW decreases HS/speed and CCW increases HS/speed, but I'm sure you already knew that. 

The more I think about it, there could also be something going on with the de-bounce "wishbone" in the gun.  You didn't by chance remove it did you?  If so, that would definitely cause some issues.  That little piece works quite well in those guns, so it could be damaged, if you didn't remove it.  My first thought still stands too, of course. 
« Last Edit: May 04, 2021, 08:53:16 PM by Rallyshark »
  • Dacula, GA
FX Maverick Compact-ish .30,.22,.177
Flash Rifle .177, 16 F.P.E Regulated(56+ shots)
PP700S-A .177 15 F.P.E. Regulated
(25+ F.P.E. unregulated)
Gamo Accu 177 pew pew pew F.P.E.

I may have Alzheimers, but at least
I don't have Alzheimers...

Online Back_Roads

  • I Got A 10 Pump BB Gun :) BB Guns Got Much More Complicated :)
  • GTA Senior Contributor
  • ******
  • Posts: 7846
  • 1st Edition Crosman 760 Pump Master
    • Back_Roads Airgunning
  • Real Name: James Seiler
Re: AT44 + reg = stumped!
« Reply #19 on: May 04, 2021, 08:57:03 PM »
 Something I have not heard of breaking recently is that wishbone debounce device ??? >>>  :-\
  • Wisconsin Collins ;Hunters Paradise; Theres a Sign in town to prove it :)
(Sorry, but you are not allowed to access the gallery)

https://www.youtube.com/channel/UC3hMPAjvTtuu7DoNzBZzuKQ?view_as=subscriber
 Below is a collection of helpful airgun videos
https://www.youtube.com/playlist?list=PLASJo4rBxMImx-kNnbppkIBV86G5Yentf