Feinwerkbau 300s - failure of recoil absorbing mech.

[gahowson]

Hi there, new to this forum, name's George, shot air-rifles a lot as a youth, mainly hunting with a shotgun since then but recently got back into air-gunning.

Recently bought a FWB 300s in good condish. (loved the look of it) and was wondering if anyone could help me out with a few questions...

Firstly was firing beautifully, incredibly accurate however...been using for HFT and now the recoiless system seems to have developed a problem. It has developed recoil, grrr. Previously the action would slide back on firing, effectively practically eliminating recoil, but now it goes back then forward again on firing creating a rather nasty, jerky recoil. It's like it travels back then 'bounces' forward.

Having followed instructions on the net, have stipped the beast down (excepting the compression chamber/spring assembly - difficulty undoing the lug - need better tools and it's siezed). There seems to be a lot of oil all over the internals including on the visible parts around the spring etc. I gather oil in a FWB 300s chamber is not good? (Intend to strip and clean this.) Must have been over zealous with wiping down rifle with gun oil in between sessions which has leached into the internals...

So, basically, there's only three reasons I can think off that the recoil mechanism is failing.

1. Too much oil reducing the friction on the runners to such an extent that the recoil is not fully absorbed thus the mechanism reaches the back then bounces back forward?
2. Failure of some internal mechanism which should stop the action returning forward during firing? Although I don't think such a mechanism exists as action used to sometimes slide back itself on pointing the gun down following a shot.
3. Dieseling caused by excess oil increasing power thus increasing recoil, exceeding the mechanisms capabilities? (No evidence of this, no loud bang, smoke on firing etc).

So I intend to finish stripping down the gun, try and degrease it/clean it and remove a lot of the excess oil then carefully reassamble the lot hoping that this will solve the problem.

Anyone got any ideas/tips as to why the recoil system may not be working and what I may be able to do about it?

(Can picture me rolling on my back, wagging my tail and exposing my tummy in suplication - as recommended by one of the editors - although personally I don't think it's a very nice image.)

Also, thinking about investing in a more powerful rifle for hunting/HFT, already got a fine Webley Osprey sidelever, but have fallen in love with the (previously) recoiless action of the FWB. Not too keen on getting a PCP, like the simplicity of a springer. Anyone know of any decent recoilless springers near the legal limit? Found two on t'internet: Rws 54 and Park RH93. Anyone got any experience of these and if they are any good or know of any other 'semi-recoiless' springers? Obviously seemed to die out in fashion following the advent of PCPs...

Well, thanks in advance for any replies and apologies for the lengthy entry - seem to have gleaned as much info. as I can from t'internet and would appreciate some advice regarding the above.

Cheers,

George.

[I. J.]

Welcome aboard George.

Sorry, I have no personal experience of stripping a FWB300 although I have owned one and shot a few. Nice rifles.
May I suggest the book 'AIR RIFLE AND AIR PISTOL MAINTENANCE AND REPAIR' by Q.Cobham (ISBN-10: 0-9553131-0-4 or ISBN-13: 978-0-95531310-0-3) which does a full strip and rebuild of this rifle.

PM me if you wish to know were these books are available. (I dont like mentioning another gun shops on Edds site )

ATB
Ian

[CRX]

Hi George,

Welcome to the forum.

I know that you stated that you have already looked on the internet, but if you haven't already found it this may be of interest.

http://www.pilkguns.com/tenp/spfwb300.htm

Kind regards

Robin.

[Garvin]

Welcome George. Reason 1 sounds most likely to me but I'm not sure. One of our collectables regulars, wonky donky, has long experience of working on these rifles so hopefully he'll be along with his diagnosis at some point. Is you piston bumper in good nick? (Look through transfer port, if it's yellowy brown it needs replacing).

[P30man]

I was going to suggest the bumper as well, plus have a look to see if the springs are in good nick, I stopped stripping these down a few years ago, throw them at a gunsmith now and say "FIX", its a lot easier LOL

[wonky donky]

Hi George, Welcome.

I've seen this in the past & it was caused by excess lube creating dieseling in the compression chamber ALTHOUGH TO BE HONEST THIS IS RARE, other things can give the same "feel" such as heavy grease, OR, SHOOTING, EVEN VERY SLIGHTLY, IN A DOWNHILL DIRECTION WILL ALSO GIVE THE FEELING ON A 300S? JUST A THOUGHT?

Get your self a decent 17mm spanner for the "lug"

Degrease everything!

In a unknown gun I would also replace the piston buffer, breech seal, spring set & spacer for the sake of about £50. I would also buy some FWB "Special Grease" it's about £10/12 for a very small tube but it will last for years & you can use it on PCP guns too!

Reassemble using a tiny amount of grease on all internal metal to metal parts including the trigger but nothing on the spring.

If your worried you might get spring twang when firing you can spray a small quantity of Castrol motorcycle chain wax over the pair of springs & leave overnight to dry. Anything else may move & cause inconsistency or worse!

All parts & grease are in stock at City Air Weapons & Firearms 0121 742 1329.

[The armourer]

George, welcome to the BBS,
you will enjoy this, there are some real good characters on here.

As for your gun, I would suggest that you do something about all that oil.
As regard other recoil less spring guns, I don't think you can beat a TX200SR, which I used to have and in a pique of needing money sold it, regretted it ever since.

[gahowson]

Well, thanks everyone for all the useful replies in such a short space of time!

CRX - yeah, best website I could find (only one) to help with stripping (my rifle)

Garvin - piston bumper is indeed yellowy brown so will be getting replaced

P30 man - indeed the inner workings of this behemoth are quite sophisticated but I like a challenge (although will steer clear of the trigger mechanism at present...)

Wonky donky - on discovering said problem, was indeed firing rounds into a pellet trap in a slightly downwards direction(assessing feel of trigger in my study...) so may well have contributed to the problem, although hadn't noticed it before. Figure as you suggest, might as well replace some of the parts while it's in bits anyway...was intending to acquire the necessary 17mil spanner tomorrow...

Armourer - havn't come across the TX200SR, will look into it!

Thanks again folks, will keep you posted on how I get on!

George.

[wonky donky]

This is the 300s trigger in it's free state & as near the correct orientation as I can show, if this helps?

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

[chrissy]

Is that a Rube Goldberg trigger?

Chris

[gahowson]

Got new seals and springs, degreased the lot, put back together.

Now shooting much more smoothly and with more power.

Previous spring buffer was collapsed cheese. Interestingly noticed previous two springs were both spiralling in the same direction! Must have had one replaced wrongly previously...

What a feat of engineering this gun is, beautifully designed, enjoyed stripping down...

Looking forward to testing at range...

Thanks for help folks.

G.