75 kg gas ram

[Privateer]

It is sufficient to put the tool to clean the unloaded rifle inside barrel, make a mark, then load the rifle and replace the tool and mark it with a meter see the distance of the piston.

If you elect to try this method?
Be aware!! You have a long rod down the barrel of a cocked gun!
Another problem is unless you can de-cock the gun? You'll need to dry fire it.

[Scotchmo]

The Hatsan 95 has a stroke of 90mm I believe.

model of the pistome is M90-100 with red color for 140 ATM equal to 70KG of force or yellow force 180 ATM equal to 90KG of force

https://www.gatewaytoairguns.org/GTA/index.php?action=dlattach;topic=112171.0;attach=218071

Ciao
Francesco

I have used the USA made N-Forcer gas springs in a number of gas spring conversions. They are fast-acting enough for spring guns. They can be ordered in custom pressures. They can be rebuilt, and you can adjust the pressure with the proper tools.

I found the red label or blue label to be well suited to airgun use.

http://www.n-forcer.com/content/pdf/Mini.pdf

For a 90mm stroke Hatsan, you could probably use the MF19-100 RD

Not quite 75 KG load but close. You could use the yellow label gas spring if you want the maximum spring force. The guns where I tried the yellow spring slammed badly but they did not have the volume of the Hatsan, so the yellow might work for you.

Pricier than the Chinese gas springs, but generally better quality. I used one in a gun to win the Hunter Piston class at the 2012 AAFTA Nationals.

[Privateer]

Scott,
 Your posts on the N-Forcer are my go to guides.
 

They are Nitrogen filled and I even checked on buying the equipment to charge them.

[franz62]

The Hatsan 95 has a stroke of 90mm I believe.

model of the pistome is M90-100 with red color for 140 ATM equal to 70KG of force or yellow force 180 ATM equal to 90KG of force

https://www.gatewaytoairguns.org/GTA/index.php?action=dlattach;topic=112171.0;attach=218071

Ciao
Francesco

I have used the USA made N-Forcer gas springs in a number of gas spring conversions. They are fast-acting enough for spring guns. They can be ordered in custom pressures. They can be rebuilt, and you can adjust the pressure with the proper tools.

I found the red label or blue label to be well suited to airgun use.

http://www.n-forcer.com/content/pdf/Mini.pdf

For a 90mm stroke Hatsan, you could probably use the MF19-100 RD

Not quite 75 KG load but close. You could use the yellow label gas spring if you want the maximum spring force. The guns where I tried the yellow spring slammed badly but they did not have the volume of the Hatsan, so the yellow might work for you.

Pricier than the Chinese gas springs, but generally better quality. I used one in a gun to win the Hunter Piston class at the 2012 AAFTA Nationals.

Products in the US or Europe does not matter, they must be of good quality.

Ciao
FRancesco

[havenofear]

I still say that the Crosman nitro pistons are reliable and powerful enough for the Hatsan Springers.  However, they can only be replaced the springs in the Hatsans AND NOT the vortex ones.  The reason is the plastic backstop are different.  Crosman NPXL nitro pistons can be installed in H105 - H155; NP2 nitro pistons for 55 - 95.  I have attached the installation plans that I used to convert from spring to gas ram.  My H155 is a testament to the reliability of the Crosman NP. Installed in 2012 and still as powerful as the first day.

[REACTOR - NIN]

Robert, very professional ! 2 thumbs up !!

[REACTOR - NIN]

Well, Robert have explained the procedure to convert the spring powered version to gas spring piston (strut) with proper installation.  I thankfully ,admired him, respected his sincere contribution  and experience that he share with our members of the GTA.

""Without proper installation,  even with a reliable and branded gas spring strut,  it will not be durable.""
 """"Why? .....""   "":What? ....."""




To b continue. ....

[Privateer]

Without proper installation,  even with a reliable and branded gas spring strut,  it will not be durable.

Where did that come from?
It is true but wondering where you got the quote.

[Scotchmo]

...

""Without proper installation,  even with a reliable and branded gas spring strut,  it will not be durable.""
 """"Why? .....""   "":What? ....."""




To b continue. ....

That is true.

Incorrect spacing can cause problems in short order. If you use a 100mm stroke gas spring in a gun that has a 100mm piston stroke, at minimum, you'll likely blow the internal oil past the seal. And if it tops out completely, it may beat itself to death.

You need a few mm of dead space when cocked and you need a few mm of preload so as not to top out. A 90mm stroke gun could use a 100mm stroke gas spring spaced such that there is about 5mm of preload, leaving about 5mm before topping out when fired.

You don't want to use 100% of the throw of the gas spring. 90% can work if balanced evenly. 80% would be safer for longevity. I've used more than 90% but experienced problems with oil forcing past the seal. Losing a little oil may not wreck it but it's still not good.

[REACTOR - NIN]

Robert is correct  about the layout of his installation of the gas strut in his rifles. With his application of " centering block ", "piston plate", "tube base",etc, and electrical tape to secure the gas strut in the piston and cylinder.. This is to avoid any " side load" to the chrome rod and also assist the chrome rod to move  parallel and evenly contacting with the seal in the gas strut. And also avoiding any friction and contact when the piston travel..
Scott is correct too about the spacing allowance for the lubricating oil in the tube of the gas strut and the necessary of a preload for the gas strut.
There are now 2 methods of installation,  '1' with the chrome rod in the piston, '2' with the tube in the piston. Which installation is better?  There are too many pros and cons about this issues. I will provide some informations and suggestions from some gas strut pistons company to help everyone to understand and make the right choice.  And also there are the temperature issues, storage issues and life span issues.
LOL. About the storage issues , if you chose the "method 1", or you have a gas ram piston air rifle that the chrome rod is in the piston, you need to consider and start re-arrange the storage of  your rifle soon.. 

[REACTOR - NIN]

To be continue. ..

[REACTOR - NIN]

To be continue....

[REACTOR - NIN]

Coming soon!!

[SteveP-52]

For anyone interested in the Russian gas rams, go search them on Ebay. I just passed quite a few surfing for other stuff. They also don't appear to be cheap as most prices appeared to be in the $40-$50 range.

[havenofear]

For anyone interested in the Russian gas rams, go search them on Ebay. I just passed quite a few surfing for other stuff. They also don't appear to be cheap as most prices appeared to be in the $40-$50 range.

I have bought a few Russian gas rams.  They replace the springs in the Hatsans with the longer plastic backstop.  I have not seen any Russian GRs that replace the vortex gas pistons though or perhaps I have missed those.  Anyway, the Crosman nitro pistons from the NPXL that fit the 105 - 155 Hatsans are relatively cheap.  Why bother to buy from Ebay? The NP2 gas rams fit the 55 - 95 Hatsans.  Just fabricate in delrin or aluminum those parts I mentioned in my plans and you are good to go.  They will last a long time. I have bought a few of each Crosman gas rams as spares. 

[REACTOR - NIN]

Robert, it is possible to replace the Hatsan Vortex version too, with the crosman or other brand spring piston strut . All you need is to saw out the base of the original vortex ram and modify it to fix with the strut that you want to install. Another alternative is to purchase the end cap of the spring coil version which is now available on eBay.

[REACTOR - NIN]

The base part from the original vortex gas ram....

[franz62]

For anyone interested in the Russian gas rams, go search them on Ebay. I just passed quite a few surfing for other stuff. They also don't appear to be cheap as most prices appeared to be in the $40-$50 range.

I've just been crazy now. bought was the last piece.
Price lower than those I use for work.

https://www.ebay.it/itm/Hatsan-125-gas-ram-piston-seal/162914036809?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

Ciao

[REACTOR - NIN]

Uuh La La! !! Francesco ,
you are not crazy but you are just addicted!!!!!

[Yogi]

Nin and others,

All great information Keep it coming...

All that I can add, it that 2 people who's opinion I really respect say to lube the piston, the exposed part anyway, with either moly or Kroytox, to keep the seal lubed.

-Y

I guess we should be storing our guns flat.