Inside the Feinwerkbau Model 100

[Cones]

Hi,

I bought a very nice Feinwerkbau 100 SSP pistol off the forums here last week and have been shooting it quite a lot.

It produced some brilliant groups on paper on the first evening out. So I have no doubt that the pistol was healthy as it was sold to me.

However after several hundred shots it started to behave a little bit oddly. Possibly 500 or so.

I suspected that the main seal was either dirty or OLD.

It was producing low power shots, then dumping the remaining air on opening the cocking lever.

Below is the album with the strip down photos.

http://s699.photobucket.com/albums/v...0Strip%20Down/

As you can see the main firing valve seal is a little past it's sell buy date.

I will write a bit of a guide to how to take these apart over the next few days.

I will say that I am more than impressed with the quality of the engineering in them. My FWB 103 was as new so I have never attempted to take that apart. But this was a genuine case of see what the problem is.

This was the problem.

http://i699.photobucket.com/albums/v...kbau100016.jpg


This is the solution.

http://i699.photobucket.com/albums/v...kbau100020.jpg


It also got a good clean and a light lube with Feinwerkbau Special Grease to those sliding parts.

I'll update with a bit of a guide later.

Thanks

Mark

[gingernut]

Informative as ever Mark.
To be fair 500 shots is a lot to put through a pistol that was probably leading a quiet life with its previous owner
Where do you get your seal kits from? City Air in Solihull?

[Cones]

Hi,

Yes, I did think I may have overdone it a little.

This kit was from Nikkonos on the bay. I bought it for my 103 as a just in case. So it came in handy that this pistol uses exactly the same seals. I've just ordered another kit. About £24.40 total for the three seals posted.

I took the FWB 100 out again this evening (just got back) for a bit of a test, I was so pleased with how it was shooting I shot two rounds of postal cards with it. The first few cards were as good as I can do with my LP10E.

I just need to chrono it again now to tune the velocity to the factory recommended 150m/s or 493 fps. I suspect it may be a little over this at the moment. It has a tiny amount of muzzle flip compared with the Steyr. It also feels front heavy, but in a good way.

After shooting both tonight I have altered the rake angle on my Steyr grip, as I realised I was not fully locking out my wrist. The end result was better groups, time will tell if it is more than just my concentration.

Thanks

Mark

[Cones]

Feinwerkbau Model 100 Strip Down Guide

Tools
Metric Hex Keys, Metric Ball driver Hex
A Decent Screwdriver set (Not some old chewed up thing) with cross point and flathead tips
Kitchen Roll
Cotton Buds
A few plastic containers for all those numerous parts
A non scratching plastic tool for removing the ‘E’ clips with. I used an old orange peeler
I did not use any gun oil as cleaner on this pistol as it is a single stoke pneumatic and oil is not really a very good idea on the seals or in the compression tube or firing valve. You can use Feinwerkbau Special grease for lubrication as it will not combust at high pressures like normal grease will.

Dismantling the Pistol

NEVER attempt to disassemble the pistol in the cocked state

Grip

Remove the Two grip screws and the two half’s of the grip.

Pump Mechanism

Undo the cross head screw under the barrel at the very front of the pistol. Wiggle the aluminium front cover away from the barrel and the end of the pump tube extrusion.
http://i699.photobucket.com/albums/v...kbau100023.jpg

Slide the top aluminium barrel cover along the dovetails and off.
http://i699.photobucket.com/albums/v...kbau100028.jpg

Undo the two hex head cap screws on the left and right side of the pistol just above in front of the trigger.
http://i699.photobucket.com/albums/v...kbau100032.jpg

Now you need to cock the hammer spring ONLY. Do this by lifting the breech cover all the way back till it clicks. You are doing this to move the small rod on the top of the pump tube forwards and out of the way. You should now be able to slide the pump mechanism forwards and down away from this rod. Now gently decock the hammer by pulling the trigger while holding the breech cover.
http://i699.photobucket.com/albums/v...kbau100033.jpg


You should now see the valve return spring and the main air valve. Gently lift the spring and valve out of the pistol body and you can then inspect the main valve seal.
http://i699.photobucket.com/albums/v...kbau100087.jpg

http://i699.photobucket.com/albums/v...kbau100088.jpg

The seal is in two parts, the bit next to the pistol body is brass, this is covered with a plastic seal. The original seal looked to be a greenish translucent plastic. But the new one is white in colour.

http://i699.photobucket.com/albums/v...kbau100016.jpg

http://i699.photobucket.com/albums/v...kbau100090.jpg


Pump Piston

On the end of the pump cylinder are two cross head countersunk screws. Undo these and remove the two half moon pieces of metal. You should now be able to slide the pump piston and handle along and out the end of the pump body. This may be messy as there is grease on the pump seals and sliding parts.
http://i699.photobucket.com/albums/v...kbau100094.jpg

You should now see the piston seal on the end of the piston. Mine is green and is currently O.K but the new one I have is red in colour.
http://i699.photobucket.com/albums/v...kbau100096.jpg

http://i699.photobucket.com/albums/v...kbau100098.jpg

You may wonder what the screw thread and ring behind the piston is for? Well it is there to adjust the automatic cocking feature of the pistol. Normally when you fully extend the pump lever the pistol hammer cocks and the loading flap opens. If this does not happen then the ring can be wound back a little so that is does so before the pump handle reaches the end of its stroke.

Barrel and Breech removal

Undo the four hex headed cap screws on the top of the action. Carefully part the upper and lower half's. Best to lift the upper half away from the lower to avoid losing lots of tiny little parts. Take a note of and or photograph the bits that you can now see.
http://i699.photobucket.com/albums/v...kbau100047.jpg

http://i699.photobucket.com/albums/v...kbau100048.jpg

In the lower section you should be able to see the hammer (big silver oblong thing) hammer spring, dry fire catch and ball bearing. In the front section is part of the auto cocking lever cam and pin. Note that in my photo I have stupidly placed the lever onto the wrong pin, just to confuse myself later on! You may want to remove the dry fire switch and tiny ball bearing now so they don't wonder off and get lost.

http://i699.photobucket.com/albums/v...kbau100051.jpg

http://i699.photobucket.com/albums/v...kbau100060.jpg


The top half of the action you can see the breech cover spring and cam pivot pin. The small lever that runs in the slot is also able to cock the hammer when the breech cover is lifted. I did not try to remove the breech cover pins, but I did remove and clean the spring.

http://i699.photobucket.com/albums/v...kbau100057.jpg

Rear sight holding block

Undo the four hex cap screws on the underneath of the rear sight assembly, now you need to fully unscrew the velocity screw to relieve tension on the hammer spring. You should now be able to lift the rear sight assembly away from the body of the pistol. It may need a gentle wiggle to free it.

http://i699.photobucket.com/albums/v...kbau100062.jpg

http://i699.photobucket.com/albums/v...kbau100063.jpg


Hammer

You can now remove the hammer spring and hammer. The hammer has a small hardened insert that it pushed by cocking cam pin. This should just lift off. I gave all the parts a good clean with kitchen roll and cotton buds. There was a fair amount of decades old grease in there.
http://i699.photobucket.com/albums/v...kbau100068.jpg


Trigger sears

At this point I noted how nice the trigger felt before taking the pistol apart and the fact that the weight was just above the 500g ISSF rules and made the decision to leave everything exactly as it is! I think you need to push pins out of the pistol frame anyway to take out the parts. If you do feel the need then first ask yourself why?

http://i699.photobucket.com/albums/v...kbau100076.jpg


General cleaning

I removed all of the old grease I could see with cotton buds and kitchen roll. There was a surprising amount on all those sliding parts. Then before re-assembly they were treated to a sparing amount of new Feinwerkbau Special Grease. Take care clean the hole the air valve runs in as mine has bits of the old valve seal inside it.

Re-assembly

This is generally the reverse of the above, with a few special notes listed below.
When you get to the final screw that holds the front of the pistol on, before you tighten it up, half open the pump handle and sight this with the part that holds the grip. The pump handle should be perfectly parallel with it. Once it is the tighten the end screw to lock everything in place.
Once assembled then check the operation of the auto cocking with the pump handle extended, too soon in the stroke and the full pump stroke will not be achieved and the power will be inconsistent. Too late and the pistol will not fully cock. Turn the ring behind the piston seal to adjust.

Velocity should now be adjusted to 150 Meters/Sec or 492 Feet/Sec. Even at full power it will not exceed more than around 4.7 ft/lbs or so, but it does not shoot as sweet as the correct velocity of 150.


http://i699.photobucket.com/albums/v...kbau100114.jpg

Comments and additional information is always appreciated.

Thanks

Mark

[JD75]

Sorry to hear you had a problem with the pistol but glad you could fix it.

Never considered a problem with the seal as it has had very light use the last four years before that it was my Pistol HFT gun at Lea Valley so did see a bit of action then.

It took a lot of soul searching to sell it but was just not getting used by me, (two kids and a Pub to run.)

Well back to the Daisy 717 which I can justify keeping as I only paid £25 for it.

[eredel]

Sorry to hear you had a problem with the pistol but glad you could fix it.

Never considered a problem with the seal as it has had very light use the last four years before that it was my Pistol HFT gun at Lea Valley so did see a bit of action then.

It took a lot of soul searching to sell it but was just not getting used by me, (two kids and a Pub to run.)

Well back to the Daisy 717 which I can justify keeping as I only paid £25 for it.

I regret not being a bit sharper and stumping up the full price for this pistol when I had the chance...it was a bargain and like Mark I wouldn't have quibbled about a seal going after a 500 shot session!
Eric.

[mickson]

Great looking pistol, good pictures, and an interesting thread ...mike...

[Cones]

Thanks for the comments.

I had chance to do a decent amount of shooting with the pistol today.

We have a full four rack pistol silhouette setup at Lincs HFT. This was shot at a lot this afternoon.

We also have a set of three 40mm Nockover discs at 30yards. I was a bit sceptical that there were a realistic pistol target. But it is possible to hit them with a lot more frequency than blind luck. Much to the annoyance of the rifle shooter who was also plinking at them. Even more so when I pointed out the rifle target should be about 10 times smaller to make it a fair contest.

The pistol has now also been adjusted to the factory 150m/sec (492ft/sec). Even using the very low cost Geco pellets it is on average around 3fps shot to shot. Which is frankly amazing.

These are my 10m paper targets from today. The first one was a bit off until I adjusted the sights 5 clicks.

The only annoying thing is that I think I am shooting better with this pistol than my shiny new LP10E.

http://i699.photobucket.com/albums/v...ts001Large.jpg

http://i699.photobucket.com/albums/v...ts002Large.jpg

http://i699.photobucket.com/albums/v...ts003Large.jpg

http://i699.photobucket.com/albums/v...ts004Large.jpg

Thanks

Mark

[jefL]

Great article Mark, well up to your usual standard.
All I need now is a 100.
I'd have had this one but I lingered about 30 seconds too long in the pistol section before going to sales, your post saying yes you'd have it was still warm
Ah well, there will be another along eventually, meanwhile I can get back to the search for a DU10.

[BigEars]

Thanks for the comments.

I had chance to do a decent amount of shooting with the pistol today.

We have a full four rack pistol silhouette setup at Lincs HFT. This was shot at a lot this afternoon.

We also have a set of three 40mm Nockover discs at 30yards. I was a bit sceptical that there were a realistic pistol target. But it is possible to hit them with a lot more frequency than blind luck. Much to the annoyance of the rifle shooter who was also plinking at them. Even more so when I pointed out the rifle target should be about 10 times smaller to make it a fair contest.

The pistol has now also been adjusted to the factory 150m/sec (492ft/sec). Even using the very low cost Geco pellets it is on average around 3fps shot to shot. Which is frankly amazing.

These are my 10m paper targets from today. The first one was a bit off until I adjusted the sights 5 clicks.

The only annoying thing is that I think I am shooting better with this pistol than my shiny new LP10E.

http://i699.photobucket.com/albums/v...ts001Large.jpg

http://i699.photobucket.com/albums/v...ts002Large.jpg

http://i699.photobucket.com/albums/v...ts003Large.jpg

http://i699.photobucket.com/albums/v...ts004Large.jpg

Thanks

Mark

Very good shooting!

[ashoot]

I followed the instructions to remove the aluminium slide over the barrel but the slide is stuck and will not slide off, after removing the screws to remove the pump, it slid away from the barrel part of the way a stuck!.
I would appreciate some advice about moving that aluminium slide and pump.

[10/10]

I would like to thank Cones for his superb instructions on how to change the seals on a FWB 100
I followed your instructions to the letter. All done spot on

[thisisdonald]

Another thank you here.. just resealed my fwb100 and this thread proved invaluable. cheers mate.. now all I need to do is start scoring like you.. today I got a 42, 44, 44 so not too bad, but not in succession, I shot a dozen cards!! the rest werent so pretty!

[ptdunk]

Hi,
I just bought a lightly used 1988 FWB100 from Germany and it really benefited from the clean up and new seals as per you're direction.
Don't think I'd have had the confidence to do it without your guide so thanks a million!

Tried it out today......what an awesome pistol:

https://www.youtube.com/watch?v=CYyGL4hvLwQ

200g lighter than my FWB90 too, I'm well happy with it.


Cheers!

[Azmodan]

Hi
i;m having problems with my newly bought FWB100 (from egun.de).
When i got it everything was OK. After 100 pellets (and some dry-firing) it started to not eject all the compressed air (when opening the pump lever air would escape, or if i cocked the gun manually, a second burst of air would come out without pumping) and the pellet flies visibly slower.

I read that the number 9 screw (from the trigger schematic in the manual https://www.feinwerkbau.de/ceasy/mod...n.php?id=343-0) controlled the striker spring, so i screwed it in a bit. That solved the problem for a few shots, than the problem reappeared.
Now i got to the end of the screw length (no more travel space) and the gun still manifests the same problem.
If i leave it alone for some time (~10 minutes) i can get a couple of correct shots and after the problem reappears.

what could be the problem? the striker spring? the valve? the seals?

thank you