Pneuma/Hatsan AT 44/tight choke?

[uncle paulie]

If you're losing air from the seals, that would cause some loss of power(which you seem to have), but generally, tumbling is caused by contact with the crown or shroud, and you indicate that on low power, there is no problem...so I do not think the seals are the cause of the tumbling. Look to the crown.

pv

[Stefan]

OK, got the gun today. Those -011 o rings were badly cut. Unfortunately, I don't have spare -011, but I have -010 o rings. I did put them on, no cutting, it just slide's in. Worked with fine sandpaper on inner part where barrel slides in, cleaned everything up. I'm not sure is it sealing properly. I will shoot it over crony tomorrow. But his crown is a mess. I have never seen one as bad as this one. Just look for yourself.

[rsterne]

The inner edge of the crown (the important bit) is indeed very rough and will benefit from a polish.... I'm thinking that the "lip" around the crown may be intentional, however, to leave a flat, recessed shoulder for any "attachment" to butt up against and move the outer edge of the crown forward of the inner edge of said attachment.... JMO....

Bob

[Stefan]

Bob trust me, its really bad crowning. I cant make a picture looking through a barrel, those cuts are visible from the other end - exit of the barrel isnt 5.5 mm, its more like 5.3mm.

[rsterne]

I wasn't disagreeing with you, I said the inner edge looked bad.... I was just pointing out that possibly that "lip" (a mm or so out from the bore) has a purpose and it might be a bad idea to lathe it off, as an example.... Without comparing it to another gun we're both guessing.... but I can't see it being that shape by mistake.... Again, JMO....

Bob

[Stefan]

oh I c I wont touch the lip, but inner edge will be worked on

[rsterne]

 

Bob

[Stefan]

It turned out I had to remove a 2mm of the top of the barrel. Did the re-crowning, now it looks like this (I'm gonna blue the barrel again today)




I've assembled everything today, fired 10 shots over crony - they were between 950/960 fps with cpum. It seems that -010 (those fill station o rings from theoringstore.com) seals everything quite good.
Put it on a bench, target at 70 yards. Took 10 quick shots at 12x magnification (first one went over the target, its not sighted in)



I think we're on to something 'ere

[Rescue912]

Wow, that crown was a mess. I had to take a bit off of my Falcon Hunter (Hatsan 125) for the same reason.

You would hope those would be caught at the factory or at least replaced under warranty.

I pulled the thread protector off of my Pneuma just to see what the crown looks like and mine looks A-OK ...

[darryl]

Hey guys, I got the hammer spring adjustment to turn. It was very tight and adjusted to full tension. I had to turn it counterclockwise to get it to loosen up. It would not go any further clockwise. But I have a problem. The plastic ball and the spring that work with the safety button fell out. How do I get them back in? What's the process for that? Or can I leave them out and just have a manual safety. I think it's better to have a choice,but I can't figure out how to get them back in place in the detents under the safety button. Need some help with that.
Also the whole hammer spring assembly slides out in the videos I've seen, but mine won't budge. I even tried to tap it out, and it still won't move. Since I can adjust it now, I don't really need to remove that assembly, but I'd like to know what's holding it from coming out.

BTW since the adjustment was turned fully counterclockwise, and I've found a sweet-spot fill of about 150 bar. 2000 psi, can I save a bit of air by turning the spring  tension lower?
thank you,
darryl 

[rsterne]

Full clockwise on the hammer spring adjuster is MINIMUM preload.... It is at the front of the hammer spring inside the hammer.... Backing it out counter-clockwise INCREASES the preload on the hammer spring.... Glad you got it to move....   

Bob

[darryl]

thanks again, Bob!

[darryl]

OK, a small update. Everything is fine now. The little plastic ball for the safety detent fell out. I asked about and found that I'd have to remover the receiver before I could put it back in. Then I couldn't cock the rifle for some reason. So I let it and me sit a day. I went back and retraced my steps, and found that the cocking problem was me. It's cocking fine now. Two turns out on the hammer tension, and maintaining the fill pressure at 145 bar. I might have to turn the tension in a bit lower to conserve air (headed back where I started!) because I'm only seeing 20 accurate shots before the air pressure drops so low that it hammer spills what little is left (odd whooshing noise when that happens). But at least I learned something about tearing one of these down. Thanks all for the assist. Much obliged.
darryl