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FWB 124 specs

July 12 2017 at 9:22 AM
Martin  (Login 10mshooter)
YF12

Looking for a few specs on the FWB 124. Anyone know the piston diameter, piston weight, piston stroke?

Thanks!

M.

 
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Ed K
(Login ekmeister1)
YF12

I Don't Remember the Specs, but... (ARH Links Inside)

July 12 2017, 2:06 PM 

Are you just doing some research, or are you considering purchasing an FWB 124/ or you already have one?

You can make your FWB 124 a much nicer rifle with the addition of the ARH spring/seal kit, AND the right lubes. By installing the ARH spring and seal kit the velocity goes up, while the vibration upon firing noticeably decreases. That's a win-win. The cocking effort slightly increases compared to the factory set-up but barely enough to notice. After you've shot 100 rounds you won't even notice the difference anymore, unless the only springers you are willing to cock are an R7/HW30 or a CZ630.

(BTW, my memory says the OD of the piston seal once installed in the compression chamber of the FWB 124 is VERY close to 1.100" (plus or minus a few thou), but my memory may be playing tricks on me because it's been a while since I tuned one).

Here's the ARH spring and seal kit I mentioned:

http://www.airrifleheadquarters.com/catalog/item/251483/8265467.htm


For the best results you'll want to get some moly paste and spring tar if you don't have some already. Easily done! ARH also sells a lube package that includes both of those (and another useful lube ) for $24. It's here:

http://www.airrifleheadquarters.com/catalog/item/251484/4169286.htm


Like I said, if you're only doing research and don't need any parts or lubes for the rifle maybe the links will be useful to someone else.


Safe and Happy Shooting!

Ed Krzynowek, The Airgun Tune-Meister


"We can rebuild the squirrel. Make him stronger, faster...We have the technology"---Skyler M.


    
This message has been edited by ekmeister1 on Jul 12, 2017 5:30 PM


 
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Steve D
(Login sd5782)
YC

28X77

July 12 2017, 10:29 PM 

I haven't had mine apart for awhile, so I hope someone else chimes in too. What I have in my notes; 28mm piston diameter. 310 grams piston weight. Transfer port is 3mm X 10mm long. Stock spring .118"

I don't remember carefully measuring stoke, but I have seen it listed as 77mm. Seems short to me. A bit mad at myself for not having a good measure in my notes, but gun well buttoned up with Macarri kit inside and loctite, so I don't want to take stock off.

 
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Ed K
(Login ekmeister1)
YF12

It Is Fairly Short As I Remember

July 13 2017, 2:06 PM 

Other air rifles with the same seal diameter produce more velocity with even a slightly longer stroke. The R9/R10/HW95 and the Beeman Kodiak/Webley Patriot all owe their high performance to a high diameter-to-stroke compression chamber ratio. Still, when you add a Maccari kit to the FWB 124 the performance is noticeably increased--it adds a nice amount of knockdown power and more yardage to its effective range.

For those who have yet to add an ARH piston seal: The fit of the piston seal will probably seem a bit on the tight side when you first install it compared to some other rifles, but if you retest the velocity in a couple of days you'll see an increase because the seal will have fit itself to the ID of the chamber. The circular valley in the face of the seal is a little wider than on some other seal designs so it takes a little time for it to reduce to the ideal size. It's not a defect--the OEM seal was/is the same way.

Sometimes it pays to turn down the ARH piston seal a few thou if the fit is VERY tight in the chamber when you try to install it. As with some other models out there, even though FWB was a high quality manufacturer, the ID of the chamber in their air rifles can vary from one specimen to the next. However, if in doubt it's better to leave the seal a little too-tight than too-loose. Like I said, it will adjust itself after a little shooting, or even after a week or so of sitting undisturbed in the closet. If you're going to adjust the OD of a piston seal, always leave the leading edge of the piston seal a little larger than the trailing edge to guarantee an airtight seal in the chamber.
Safe and Happy Shooting!

Ed Krzynowek, The Airgun Tune-Meister


"We can rebuild the squirrel. Make him stronger, faster...We have the technology"---Skyler M.

 
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Martin
(Login 10mshooter)
YF12

Thanks Steve!! That's what I was looking for. NT

July 13 2017, 4:51 PM 


 
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