Hatsan Dominator Basket Case

[Ronno6]

I purchased a true basket case Hatsan Doninator .177.
Arived in parts and baggies.
Needed the Vortex ram re-sealed, new pistom seal and breech seal.

I had not worked on one of these before, so I was covering new ground.
A few pieces were foreign to me, but I managed to ger 'er back together.
Once te breech seal gets here I'll see if my repairs were successful...

[Ronno6]

I have found that you can't replace a Vortex type 4 ram with a Type 1.................even if it has the funky breech block...

Now, IF I could only figger out how to get those darned O-rings into the gland, I'd be set!!

I replaced the O-rings on 2 vortexs rams without a problem,
But, I HAVE LOST THE KNACK..............

Any hints would be appreciated..........

[mikeyb]

If you removed the old o-rings the new ones should go in. I did it on 2 Vortex air springs but neither one was easy for me. The new o-rings were a tight fit and required several attempts to get them to POP in just right.

[Ronno6]

A new wrinkle.........

The Dominator, being an under-lever cocker, does not directly connect the lever linkage to the piston.
Rather, it cocks the sleeve, which actually is the air chamber.
The sleeve then moves the piston inside, which is what must travel far enoufgh to latch.

When assembled, the Doninator simply will not latch when cocked.
The travel of the piston lacka approximately 1/32", possibly less,of travel to allow the sear to engage.
I determined this by removing retaining pins from the ram and safety block and cocking.
The ram and safety block barely move but they DO movewhen the piston and air chamber sleeve latch ........
This means that the ram piston is bottoming out before the piston has traveled enough to latch.

The sleeve (air chamber) must also move enough to engage the side lock.
Not doing that either.....

I replaced the piston seal with one from ARH.
It does protrude slightly from the front of the center nub of the piston.
Gotta be the culprit......... it is the only variable here.
Mayme I should ask Mr. Jim ??

Should I remove a bit of the front seal??
I would have to believe that that bit of seal would deform with repeated cycles.......

Looking at it, I woud think that if the seal is the culprit, the piston would engage the sear, but the sleeve might not latch with the side lock..(lever lock)
Dunno.....befuddled.....

Other option would be to remove a bit of material off the end of the ram of the Voretx cylinder.
As I do not as et have the Vortex reassembled, I could take it off the button head screw on the inside end of the rod.

Geeeeeeeez, there's so much to learn here.

[mikeyb]

If anything a "thick" piston seal should move the piston back MORE so the trigger should latch a little quicker.

The Dominator originally came with a coil spring and a piston with no "dimple" inside to catch and center a Vortex shaft.
If your rifle piston does NOT have that dimple inside the piston will not go far enough back before the Vortex "bottoms out" and piston will not be able to catch the trigger latch.

Is it possible someone tried to UPGRADE an old Dominator from a coil spring to use a Vortex air spring but failed due to no piston dimple?

Check the inside of your piston for the Vortex dimple. If it HAS the dimple maybe the cocking link/shoe is bent/damaged?

I don't recommend modifying the Vortex air spring itself as that is a bandaid fix for some OTHER problem.

[Ronno6]

Yup.
I agree with you that the piston should latch.
The ram dimple IS there.........
And, as the outer casing of the gun says "Vortex" that precludes a conversion attempt.

Cocking arm not bent, as it will cock once the ram and safety block are un-pinned.

I do not like bandaid fixes. I would rather fix the problem
But, I have yet to identify that particular gremlin.

Somehow or other, the ram is bottoming out before the piston is latching.
So confused.......

[Ronno6]

Near as I can measure,there is about .039" I need to find somewhere.
That is about the amount of movement in the ram,safety block needed to achieve a latch.

There is 3/8" of preload........

[Ronno6]

I have another shafr that I believe is from a different Vortex ram.
It IS possible that I got things mixed up while apart, but not likely IMO.
This shaft is shorter.
That would eliminate the cocking problem, but there would only be about 1/16" or so of preload......
I don't think that would do.......

[mikeyb]

I have another shafr that I believe is from a different Vortex ram.
It IS possible that I got things mixed up while apart, but not likely IMO.
This shaft is shorter.
That would eliminate the cocking problem, but there would only be about 1/16" or so of preload......
I don't think that would do.......

Preload is ONLY there to prevent that wimpy little "shaft retaining screw" from hitting the brass "gland" during a shot. As long as preload NEVER gets to 0" everything should work just fine.

[mikeyb]

fyi...

I don't own a Dominator but I do remember a few GTA members posting about them (4-5 years ago?).

My (limited) recollection was that a few who purchased closeout Vortex Dominators didn't like the cocking effort or shot cycle. I think some converted their Vortex rifles to use coil springs and preferred the results.

Regardless, hope you get it working again :-)

[Ronno6]

I have another shafr that I believe is from a different Vortex ram.
It IS possible that I got things mixed up while apart, but not likely IMO.
This shaft is shorter.
That would eliminate the cocking problem, but there would only be about 1/16" or so of preload......
I don't think that would do.......

Preload is ONLY there to prevent that wimpy little "shaft retaining screw" from hitting the brass "gland" during a shot. As long as preload NEVER gets to 0" everything should work just fine.

Yessir. I'm aware...

but that is a tad close for my comfort.
As I have more than 1/4" to play with,
I could turn a 1/8" thick spacer to put in front of the rod to give a bit of margin....

As for converting to coil, simple enough, except I cannot put the fixed barrel into my spring compressor.
I am using a scope rail mounted compressor with the gas ram setup....

[mikeyb]

Adding a spacer in front of the rod would only make the problem worse. I'm more confused now so I went back to re-read the thread.

Near as I can measure,there is about .039" I need to find somewhere.
That is about the amount of movement in the ram,safety block needed to achieve a latch.

There is 3/8" of preload........

IMO that is too much preload and the reason it is not working. Something is not right. I usually see about 1/8" preload when working with air or gas springs. If all the correct parts are in the right place a preload of 1/8" is perfectly safe.

[Ronno6]

Odd thing is,
When the rod is fully retracted, the longer rod protrudes about 1/2" from the gland.
That seems about right.
The shorter rod only protrudes about 1/8"......
But the taper on the end of the shorter rod is a lot shorter than that on the longer rod..possibly
to keep the tapered section from reaching the O-ring when retracted ??

[Ronno6]

OK.
Back together, resealed Vortex 4 with the shorter rod, no spacer, 1/16" of preload.

I got REAL good at assembling this critter.

It cocks, it SHOOTs......boy, does it shoot!

No sights on it (no mounting provisisons, never had sights..) so I'll need to scope to see if I can hit anything with it
For the time being, a bunch of parts are now a functioning air rifle !!