Picked up an FWB Sport finally. Quick tune results.

[Sqwirl57]

As pretty much everyone knows, the FWB Sport is a jumpy, slammy, godawful shot cycle from the factory. Ran some pellets over the chrono and was getting 860fps with both the JSB 8.44gr and the FTT 8.64gr. From my experience, the FTTs are usually a good 20-30fps slower so it was a safe bet the Sport was a bit over sprung. Cutting a single coil would likely soften the shot cycle some while maintaining a very similar velocity withe the JSBs. I opted to remove 2 coils though and hopefully really tame the beast.

I removed the spring (guide is just as poorly fitted as expected), snipped and flattened two coils, relubed, and reinstalled everything. Re ran the JSBs over the chrono and sure enough I was still sitting at 835 fps with the JSBs with the added benefit of a much tamer gun. With only 200 shots or so on it now, I expect it to only get better with time. When I have a bit more free time I'll turn myself a proper guide and call it a day. Here is a shot cycle comparison between my HW50S (stock spring, Vortek piston seal) and the FWB Sport.

 

[ChuckHunter]

Vortek 30mm HW80 seal will fit the sport too!

 

[Sqwirl57]

Vortek 30mm HW80 seal will fit the sport too!

Good to know! I actually have an ARH seal here for it. The factory one is loose but no where near as loose as I expected. Of course the ARH seal was delivered an hour after I put it all back together

When I make the new guide I'll probably install it. I may even take one extra coil off but I haven't decided yet. I'll let the spring settle in some first

 

[Michigander]

Sounds like yours was running a little hot initially. My Sport settled in at 830 fps shooting AA 8.4 with stock spring and seal. It has been so accurate in the stock configuration I have been reluctant to fiddle with it, thinking that just maybe FWB knew what they were doing when they designed the power plant. Is it possible that the preload was intended to control piston bounce? Is that the secret to its combination of fine accuracy and relatively high power level? At any rate, once broken in the shot cycle does smooth out noticeably, and while still abrupt, does not seem to present a barrier to accurate shooting. Which is all I am really interested in.

 

[Sqwirl57]

Sounds like yours was running a little hot initially. My Sport settled in at 830 fps shooting AA 8.4 with stock spring and seal. It has been so accurate in the stock configuration I have been reluctant to fiddle with it, thinking that just maybe FWB knew what they were doing when they designed the power plant. Is it possible that the preload was intended to control piston bounce? Is that the secret to its combination of fine accuracy and relatively high power level? At any rate, once broken in the shot cycle does smooth out noticeably, and while still abrupt, does not seem to present a barrier to accurate shooting. Which is all I am really interested in.

It was very accurate right out of the box in all honesty. If it didn't slam home so much I would have left it be. That wasn't the case unfortunately though. My groups have only improved since making the cuts so at the very least I didn't hurt anything in the accuracy department. As far as piston bounce goes, I didn't notice any before hand and I still don't notice any now, even with the heavier JSB 10.3s

 

[ChuckHunter]

Good to know! I actually have an ARH seal here for it. The factory one is loose but no where near as loose as I expected. Of course the ARH seal was delivered an hour after I put it all back together

When I make the new guide I'll probably install it. I may even take one extra coil off but I haven't decided yet. I'll let the spring settle in some first

Yeah I bought the ARH seal too.
But after talking to Tom at Vortek and taking some measurements we came up with a kit that works really well!
Went to a .148 wire spring at 26 coils with a tight fitting guide and his 30mm seal and the shot cycle is awesome! I'm running at 790 with 8.4 AAs in 4.51 head size and it's accurate as hell. After a couple hundred rounds I adjusted the trigger and it's becoming one of my favorite springers!

 

[Michigander]

Who knows, maybe when I get around to servicing my Sport I will decide to back off on the power a bit to acheive a smoother shot cycle. Good to know you guys have had some luck doing that. The problem is I already have several springers I have tuned to 12 ft-lb or less, and wanted to keep this one above 13 ft-lb.

Question: How does one measure piston bounce/surge? It eludes me.

 

[Sqwirl57]

Who knows, maybe when I get around to servicing my Sport I will decide to back off on the power a bit to acheive a smoother shot cycle. Good to know you guys have had some luck doing that. The problem is I already have several springers I have tuned to 12 ft-lb or less, and wanted to keep this one above 13 ft-lb.

Question: How does one measure piston bounce/surge? It eludes me.

Bounce as far as I know is something you can feel/hear. I only have one gun where its very noticeable in and that is my HW57 and only with heavier pellets like the 10.3s or the 10.65s. When I pull the trigger the spring makes a deathly sound like it wants to break. Its kind of buzzy and the recoil/shot cycle just feels very wrong.

I am far from an expert though so take that with a grain of salt until a more experienced person chimes in.

 

[Feinwerk]

Looks pretty nice, and 835 fps is still quite snappy! If it just goes 'thuk' with no buzz or vibration, you've nailed it. I have an original 124 s from the late 70s that I rebuilt and that's what it's shot cycle is like. It only makes around 805 FPS or so.

I didn't notice much or any forward snap at the end of the shot cycle from either of your rifles in the video. They both look equally mild, exhibiting only the rearward recoil as the piston moves forward. If the piston was over sprung and slamming from the factory, you seem to have tamed it. When the piston slams, you can feel the pulse of extra vibration in the stock, and it jerks the whole rifle forward a bit. That reverse snap is what makes scopes creep backwards on springers (or breaks reticles), unless you have very good clamping or a scope stop pin in one of the rings.

I used to own a vintage HW50s from the 70's, before they beefed it up. It only made around 660 fps IIRC. It barely moved on the bag and was very easy to shoot accurately; a real pussycat that was super easy to cock and shoot with the Rekord trigger. Great youth gun. After doing a Lube tune and spring replacement and seal replacement, I had it all cleaned up and passed it on to my nephew to share with his two boys when they come of age. I may regret giving it away, but it's still in the family. These classic old springers are kind of like heirloom quality.

 

[pmg]

ChuckHunter, thanks for the info on the Vortek spring that you used on your Sport. Upon looking at their website there are a number of 148 spring OD’s, would you happen to remember which one you used and also did you use a Vortek spring guide? Sorry for all of the questions but I’m trying to get to the same happy place that your at with yours!