Inside the Feinwerkbau Model 300s

[zooma]

Hi,

Yes, it is here at post number 20.

http://www.airgunbbs.com/showthread....04#post4545004

Thanks

Mark

Thanks for that Mark,

I am guessing most of this will also apply to the Model 80 and so it is a very helpful reference I will make good use of as I work on both types.

Maybe Feinwerkbau should offer the type of video's Steyr offer to show some of the basic strip and repair jobs, but if they did I guess it would only be for the current model range, but since all of the FWB models are still so popular there must be an oportunity to offer this valuable service?

Lets hope somebody responds to the idea for the benefit of us and future generations of Feinwerkbau collectors, users and enthusiasts.

[Cones]

Feinwerkbau Model 300s Strip Down Guide

Tools
A Decent Screwdriver set (Not some old chewed up thing) with cross point and flathead tips
Needle Nosed Pliers
Kitchen Roll
Cotton Buds
Brunox Turbo Spray or similar light Oil for cleaning metal parts
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
Autosol Metal Polish


Dismantling the Rifle

NEVER attempt to disassemble the rifle in the cocked state

Remove the Two stock screws and separate the stock from the action.

Sliding Carriage
The rifle is able to slide on this metal carriage to absorb the felt recoil during the shot cycle. It is held in place via two front slide pins, a cross pin and a single rear block.
First remove the cross pin by taking off one of the 'E' clips and slide it out of the carriage.

http://i699.photobucket.com/albums/v...ir031Large.jpg

Remove the front spring by carefully lifting the top part with a pair of needle nosed pliers.
http://i699.photobucket.com/albums/v...ir022Large.jpg

The two front pins are held in place with two small 'E' clips. Remove the clips with a small screwdriver blade or non scratching plastic tool.
http://i699.photobucket.com/albums/v...ir034Large.jpg

Slide the pins out of the housing.

http://i699.photobucket.com/albums/v...ir046Large.jpg

The back of the carriage sits on the rear sliding block.
http://i699.photobucket.com/albums/v...ir041Large.jpg

You may need to wiggle the carriage or use a wooden dowel to pry it away, it should just pop off.
http://i699.photobucket.com/albums/v...ir041Large.jpg

The rear block should now slide out of the action. It may need a few gentle turns to persuade it.
http://i699.photobucket.com/albums/v...ir043Large.jpg

Trigger Group

The whole trigger system is held in place by just two screws.
http://i699.photobucket.com/albums/v...ir037Large.jpg

http://i699.photobucket.com/albums/v...ir038Large.jpg

Remember the long one is at the front!
Remove both of these and gently rock the trigger group from side to side until it comes away from the rest of the action.
http://i699.photobucket.com/albums/v...ir051Large.jpg
http://i699.photobucket.com/albums/v...ir059Large.jpg


Cocking lever

The lever is retained with a single screw located at the back of the top slide. The flat headed screw may have been retained by a couple of punch marks to the main frame. But you should still be able to turn it out carefully. Once undone the lever can be removed from sliding breech.
http://i699.photobucket.com/albums/v...ir068Large.jpg
http://i699.photobucket.com/albums/v...ir071Large.jpg
http://i699.photobucket.com/albums/v...ir073Large.jpg

Anti Bear trap spring

As well as a cocking lever ratchet device that you have already removed with the trigger group. The 300s has an additional safety feature in the form of a sliding gate that retains the piston in place until the cocking lever is fully closed.
To remove this leaf spring first take off the 'E' clip located on the pin in front of the cocking pivot point.

http://i699.photobucket.com/albums/v...ir076Large.jpg
http://i699.photobucket.com/albums/v...ir077Large.jpg
Then carefully lift out the retaining pin, actuating button and leaf spring. The leaf spring may need to be rotated 180 degrees to remove it.
http://i699.photobucket.com/albums/v...ir080Large.jpg

Main Spring

With the above components removed the main spring can be accessed by first clamping the rifle between the front of the barrel and the rear block that the cocking lever was attached to. Please use wood blocks or plastic clamps to avoid marking the metalwork. I did not have a clamp so I used a block of wood and held the action muzzle up with the wood block on the floor. The wood block was used to keep the weight away from small thin metal strip at the rear of the action as it will bend easily. There is a reasonable amount of preload on the spring, I am comfortable holding against this weight. You may not be, if in doubt use a clamp.

Loosen the main bolt with the correct size open ended spanner, while keeping pressure on the rear of the action and fully remove the bolt. Then gently release the clamping pressure and the rear of the action should slide out of the rest of the cylinder. If it is stuck then replace the screw partly and gently tap it with a soft mallet to loosen the two parts. Don't do this without the screw in place or the end will fly out and do some serious damage.

http://i699.photobucket.com/albums/v...ir083Large.jpg
http://i699.photobucket.com/albums/v...ir086Large.jpg
http://i699.photobucket.com/albums/v...ir087Large.jpg

Sliding gate

Remove the rear part of the action and be careful not to lose the sliding gate and spacer.
http://i699.photobucket.com/albums/v...ir088Large.jpg

Breech and Piston

Slide the spring, breech and piston out of the action.
http://i699.photobucket.com/albums/v...ir090Large.jpg
http://i699.photobucket.com/albums/v...ir093Large.jpg
http://i699.photobucket.com/albums/v...ir097Large.jpg


Cleaning

I cleaned all of the components, except the piston and breech with Brunox but any decent light oil will be suitable. Cotton buds help get into the awkward places and clean out any accumulated crud and debris. Then I wiped everything clean using kitchen roll and clean cotton rag.

The spring and piston in these rifles is designed to run free from grease or lubrication.
The trigger components can be lubricated with a tiny amount of Feinwerkbau Special grease, but this may pick up dust and debris over time, so I have just left the tiny amounts of residual oil on them from the cleaning process.
I did lubricate the slide rails and the cocking pin and release catch pin with Feinwerkbau Special grease.

Barrel Seal and Piston Buffer Replacement

The piston buffer and barrel seal may need replacing. Older seals are white in colour, newer ones are blue or green.
I had to remove the old seal with a plastic tool. It was like chewing gum and had stuck to the breech.
http://i699.photobucket.com/albums/v...ir094Large.jpg
http://i699.photobucket.com/albums/v...ir104Large.jpg
http://i699.photobucket.com/albums/v...ir107Large.jpg

I polished the Breech and piston with Autosol to remove the last of the seal debris and remove the slight corrosion.
http://i699.photobucket.com/albums/v...ir108Large.jpg
http://i699.photobucket.com/albums/v...ir110Large.jpg

New seals installed and ready to re-assemble

http://i699.photobucket.com/albums/v...ir114Large.jpg

If plastic debris is found in the barrel then the piston buffer could need replacing, which does mean you have to dismantle the rifle.

Re-assembly is the reverse of the assembly.

Watch out for the following though!
Make sure you replace the piston into the breech with the square hole for the cocking lever lining up with the slot. Otherwise you are going to swear when you get to fitting the lever and it has no hole to locate in!
http://i699.photobucket.com/albums/v...ir118Large.jpg

The sliding gate leaf spring has to go in the correct way and the tip of the spring also has to reside in the small slot cut into the sliding gate. Otherwise an important safety function of the rifle will not work correctly.
http://i699.photobucket.com/albums/v...ir062Large.jpg

I did not strip the trigger group down on this rifle as it was working perfectly. If you do then again I would advise you to take a lot of photographs and lay everything out in a logical order.

They are not too bad to do, I have done them on previous rebuilds.
Comments and additional information is always appreciated.

Thanks

Mark

[wonky donky]

This is how the trigger parts are set out in the Trigger Block but exploded on the bench so you can see each of them in turn.

http://i202.photobucket.com/albums/a...arts000307.jpg

Some rifles will refuse to fire when the trigger is pulled, not all the time, but occasionaly. They are then in a very dangerous state & will fire at the slightest knock.
This is not caused by parts in the trigger or anything mechanical in the rifle. It's the rear screw that goes through the trigger block causing the centre of the block to twist between the plates.

If you have this problem, and only about one in about 500 guns suffer this, slacken the screw off, Loctite the threads with the sort of Loctite that is easily undone with hand tools. Then put the screw back with the washer sitting on the block & the screw head just contacting the washer. Do not tighten. Problem gone!!!

[Cones]

Brilliant, any extra information is very much appreciated.

This way we end up with a valuable resource to help people with these older rifles.

Thanks

Mark

[zooma]

My FWB 300S is original and has never been "opened" from new.

I have been told that the more recent replacement parts have benefitted from the improved materials now available, and once rebuilt the rifle is unlikely to need a similar rebuild for a much longer period of time than the original factory built components were able to offer.

Given the superb build qaulity of the 300S and the lengthy service times already acheived from new, this should ensure these excellent match rifles will be with us and working well for many more generations yet!

[zooma]

Thanks for making such a great effort to document and picture the 300S strip-down and rebuild.

I have a 300S that has never been touched from new and would benefit from the same treatment, so I am inspired to" give it a go"

Extra tips like the one from wonky donkey are also very helful.

[zooma]

I took my elderly 300S to the club last night to give it a few rounds prior to the rebuild that I though would be needed after such a long "rest".

To my amazement the "old girl" performed brilliantly sending the pellets down the range a a fair old pace. I will get a chrono on it later and see what speed I am getting, but from what I saw last night I am thinking it is best to leave well alone and delay a rebuild until I see a degrading of the performance.

My only concern (given the age) is that "prevention may be better than cure" as I know some of the original materials used were not as good as the modern replacements.

Any thoughts about this?

[Cones]

Hi,

You can see the main seal when you open the breech up. Is it in good condition and what colour is it?

The original factory fit ones were white in colour. If it is white then it is probably due for replacement.

I agree with not taking things apart for the sake of it, you could potentially do more harm than good in some instances.

But it you are well informed, have the correct tools for the job and have a genuine problem to fix or solve then go for it.

Mark