Regulating the Hatsan AT44 in .177cal

Regulating the Hatsan AT44 in .177cal

Joined: October 25th, 2002, 3:46 pm

April 9th, 2012, 9:55 pm #1

Building regulators for the Hatsan AT44 series of PCP rifles.
This rifle is the AT44 .177cal Long with LW barrel. Shooting Crosman Ultra magnums for testing.
Fills to 3,000psi shooting down until the numbers fall.
first pic is 0 turns hammer spring for 20 shots then 1 turn for the remainder
second pic is 2 turns hammer spring.

Walter....

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Joined: September 15th, 2000, 3:23 pm

April 9th, 2012, 10:14 pm #2

I know you are probably just getting started as far as getting everything set just where you want it. Looks to me like you could probably turn that puppy down to about 1800-1850 and be good to go for a shot string.

Regards,
DaveG
See more picts @http://davegcustomstocks.com
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Joined: October 25th, 2002, 3:46 pm

April 9th, 2012, 10:19 pm #3

Finished the machining efore the weekend, assembled the reg this morning and threw it into the tube to see what happens.
So as you say no real setting up or tweaking other than the hammer spring.

Cheers,
Walter....
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Joined: September 15th, 2000, 3:23 pm

April 9th, 2012, 10:28 pm #4

on your first string with the single turn of preload, looks like a little "valve lock" at 2000 psi set pressure, due to the fact that you got such a good increase in velocity by altering the spring preload.

On string 2 it looks like a nice blip at around shot 48, 49, 50, where you probably dropped off the reg. Best of both worlds would be to drop the set pressure, and stick with the lighter strike, I think... Looks to me like you could keep that thing humming right at the 900fps (maybe just a hair under) range for a really good number of shots.

I know how it goes. You'll be playing with that thing for quite some time...

Regards,
DaveG
See more picts @http://davegcustomstocks.com
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Joined: December 9th, 2004, 10:14 pm

April 10th, 2012, 12:01 am #5

Building regulators for the Hatsan AT44 series of PCP rifles.
This rifle is the AT44 .177cal Long with LW barrel. Shooting Crosman Ultra magnums for testing.
Fills to 3,000psi shooting down until the numbers fall.
first pic is 0 turns hammer spring for 20 shots then 1 turn for the remainder
second pic is 2 turns hammer spring.

Walter....

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Sweet job, Walter. Are you considering production of a .22 caliber regulator as well?
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Joined: October 25th, 2002, 3:46 pm

April 10th, 2012, 1:03 am #6


AT44 regged .22 at 2,000psi

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AT44 regged .22 at 1500psi

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At44 regged .25 at 2,000psi

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Joined: April 16th, 2010, 8:09 pm

April 10th, 2012, 2:19 am #7

Very good, Walter. Regards, Tom

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Joined: October 25th, 2002, 3:46 pm

April 10th, 2012, 8:36 pm #8

on your first string with the single turn of preload, looks like a little "valve lock" at 2000 psi set pressure, due to the fact that you got such a good increase in velocity by altering the spring preload.

On string 2 it looks like a nice blip at around shot 48, 49, 50, where you probably dropped off the reg. Best of both worlds would be to drop the set pressure, and stick with the lighter strike, I think... Looks to me like you could keep that thing humming right at the 900fps (maybe just a hair under) range for a really good number of shots.

I know how it goes. You'll be playing with that thing for quite some time...

Regards,
DaveG
See more picts @http://davegcustomstocks.com
needs optimizing.....

got a 20 shot string of 958ave with the 20th at 954 and teh next ten steady drop to 884.

Was using about 1.5x as much air per 10 shot string. So tried the hammer at 0 turns and teh velocity went to 945fps ave with the same trend and air consumption.

These Hatsans have a very weak valve spring and so figuring to get more snappy closing as well as being able to tune back with more hammer spring.

Walter....
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Joined: September 15th, 2000, 3:23 pm

April 10th, 2012, 9:24 pm #9

I'm suprised at how much the velocity went up when the reg was turned down. A lazy closing valve doesn't always lead to higher velocity, but for sure more air used per shot...

I looked at mine breifly today, but think it is just enough different than yours as to not be of much help. As previously stated, mine doesn't have the Quatro, and I have no preload adjuster either...

Don't know how much work you want to put into it either. I think a much lighter striker spring can be used, as well as a lighter striker. As you may know, in my own valves I have gone to using a very, very soft return spring. Not much more than that found in a ball point, click type pen. I think that FX uses something along the same lines in many of their valves as well. It takes some doing to find just the right balance between striker weight, and pre-load, but when I hit it, it seems to work out well for a good shot string.

Anyway, have fun with it Walter. I look forward to reading your results!

Regards,
DaveG
See more picts @http://davegcustomstocks.com
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Joined: October 25th, 2002, 3:46 pm

April 11th, 2012, 8:58 pm #10

this is likely the way I need to set them up. The 2,000psi forces the owner to use the hammer spring adjuster to increase velocity.
The economy is much better with the gun near valve lock.

Walter....

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