FWB300S service/mainspring

[Nikkormat]

Has anyone tried the "Plus" service kit for the FWB300S from Waffencenter Gotha? It has a stepped piston ring and a heftier spring.

I've just got myself a well used 300S Junior. It seems to shoot well, but is low powered as it's come from Germany - probably around the 5ft.lb mark. OK for 10 metre, obviously, but I want this to be my 50 metre plinking rifle, so 8ft.lbs would be nice. I've not stripped one before, so any advice is appreciated. I've seen this strip and rebuild on Youtube and it doesn't look too hard. Any thoughts on lubrication? I know they were meant to run dry, but it seems some people favour a tiny amount of grease - how about Feinwerkbau's own grease?

Cheers,
Matt

[Eidem]

Congrats with the junior! I want me one of those too!
Stripping and rebuilding is actually quite simple even if the gun is mechanically advanced.
Take some photos of it when you take it apart to be sure. also make sure you do not
loose any of the clips you have to take of. I also just watched the strip and rebuild video
on youtube, no worries!

There is no need to lube the inside as it has a spring seal as a car cylinder would have.
It will probably just scrape of the lube again.
So said I did actually give my FWB 80 a tiny amount when I stripped and rebuilt it, I did
not intend to do so, habit just got the best of me. It dieseled some for 50+ shots which
only lead to me having to clean it a lot and now wanting to strip it again.

Give the rest a thin! coat of moly, I am sure the Feinwerkbau grease is fine to.

When I get new seals and spring for my 300s I will not put any lube inside the cylinder

I got two FWB 300s guns one is tuned, I am not sure which spring it has, but it is clocked
at the same velocity as the Maccari springs. The other one is original.

The original one is much easier to shoot at long range. They both are able to produce around
5mm groups at 45m, but the tuned one is much more hold sensitive at that range.
While the original one can do this over and over the tuned one torques a little when fired and
there is often one pellet escaping the group of five. The original spring being two pieces might
be what makes the gun torque less.

I am putting an original spring into it again as it is simply better. The original one has about
3 cm more of a drop at that range compared to the tuned one. At 10+20m, there is no
noticeable difference in accuracy.
As long as you only want to shoot targets the original spring is more than adequate the purpose,

B.R. Kris

[Nikkormat]

Thanks for your reply Eidem. I've not had chance to give it a proper long range test yet, but I thought as it almost certainly needs a service I might try something other than standard inside. Reading your experiences now, I might well stick with the factory parts.

It's an ex-club rifle, made in 1982 I think, some pitting on the top of the cylinder and scratched woodwork, but it seems mechanically fine. The breech seal is blue, but that doesn't necessarily mean the buffer has been replaced as well; looking through the transfer port it looks yellowish.

Compared to my standard 300S and 150, the handling is superb; it's like a sturdy sporter. I'm going to extend the butt a couple of centimetres and fit a small scope.

Matt

[Eidem]

Youtube is full of videos of people shooting with Maccari springs, but I am starting to believe it is a hype?
Just because so many people will only look at velocity when buying an air rifle. I believe once you have
fitted a new spring and broken it in, you will be pleased by its performance. I do not know for the rifle, but
for my model 80 it took about two tins of pellets before I noticed that the spring had broken in.

One thing I have noticed thought; scope weight! As the gun is sliding back and forth to be recoil less, the
scope also slides back and forth bringing momentum to the movement.
I would highly recommend being a weight weenie on the scope. The lighter the scope is, the smoother the
gun will shoot. Thought this is a back and forth force it does not affect the accuracy in the same way
that the spring seems to do. More the feel of the gun and is most noticeable on my original gun as it is
so much smoother.

If the buffer is old I would replace it! As I understand, if that breaks you could end up doing some damage to
the internals. And if it is white turned light yellow, most likely it is 30+y old.

I m getting a full original service kit for mine. Pricey as it will come in at around £60 shipped, but it is in my
opinion worth it, and honestly I would never consider any alternative. The gun is a legend for a reason

B.R. Kris

[u.k.neil]

In the last two weeks I have done two FWB300S's and in both cases the piston buffer had totally disintegrated and all that was left of them was dust.

Neil

[wonky donky]

In the last two weeks I have done two FWB300S's and in both cases the piston buffer had totally disintegrated and all that was left of them was dust.

Neil

Yes Neil I have had lots like that, the worst thing you can do is not shoot these rifles. I don't know why for sure but Walther LGR, FWB300 & Diana/Original all fitted with the whitish/yellowy seals will revert or disintegrate if left standing unused for long periods of time. I think this is due to the minute particles of lube creeping from the seal. If the rifles are well used there doesn't seem to be so much of a problem. FWB & Diana have now changed the material but the LGR still soldiers on with the same spec replacement part.

BSA Meteors, Airsporters & derivatives have the same problem with the buffers.

Also with the 300s I have had to replace compression tube because the cocking lever has pulled out ripping the metal away due to non genuine springs being put in to gain more power, admittedly these were rifle used 2/4 times a week for a few years but non the less it happens.

[Nikkormat]

Thanks guys.

Also with the 300s I have had to replace compression tube because the cocking lever has pulled out ripping the metal away due to non genuine springs being put in to gain more power, admittedly these were rifle used 2/4 times a week for a few years but non the less it happens.

Your comment Wonky, after Eidem's, is pushing me in the direction of fitting a factory standard spring. As I don't hunt, I suppose I can live with "out of the box" power.

Any more opinions are most welcome.

Matt

[wonky donky]

Thanks guys.



Your comment Wonky, after Eidem's, is pushing me in the direction of fitting a factory standard spring. As I don't hunt, I suppose I can live with "out of the box" power.

Any more opinions are most welcome.

Matt

You can fit a Feinwerkbau 150 single piece spring it will give you marginally more power.

I notice Eidems's comment on "breaking springs in" with a genuine Feinwerkbau spring there shouldn't be any breaking in period, they are bound to be at least double scragged, I have removed springs from rifles & pistols that have had 20yrs of use showing only 5mm of reduction on the overall length & I have never seen a genuine Feinwerkbau spring broken.

I'm sure the bedding in is not due to the spring but something else, probably lubrication. If you could strip a new 300s or 65 pistol you wouldn't see any lubrication in the compression tube, any visible lubrication would be confined to the safety areas, trigger pins & on the edges of the sears.

There are a couple of well known spares suppliers selling pairs of springs in the UK for Feinwerkbau rifles at a very low price compared to the factory item, I would suggest these are worth steering clear of as are the after market Breech Seals & Piston Buffers.

[Nikkormat]

Thanks again Wonky. Factory it is, I think.

Matt

[Eidem]

I notice Eidems's comment on "breaking springs in" with a genuine Feinwerkbau spring there shouldn't be any breaking in period, they are bound to be at least double scragged, I have removed springs from rifles & pistols that have had 20yrs of use showing only 5mm of reduction on the overall length & I have never seen a genuine Feinwerkbau spring broken.

I'm sure the bedding in is not due to the spring but something else, probably lubrication.

After about 2 tins of pellets my FWB 80 "loosened up" and became smoother, also I am sure there has been an increase of power. I have no chrono,
so I have not measured it. But yeah it might have been the piston seal breaking in and the lube leaving the chamber? But it just felt "looser" and
more "natural and settled" if you understand what I mean?

"Double scragged" what do you mean by this?

One of my 300s guns is still original, both seals and spring, it is more accurate than all the ones I see at youtube. It was a links gun left unused at a
local club for decades. I realize the need for replacing the rubber in this one, but I am VERY hesitant about opening a gun that shoots 5mm groups at 45m.
But then again it is no use of having it if I am afraid to use it either.....

[wonky donky]

"Double scragged" what do you mean by this?
.

I have springs made for the tunes I do to sporting rifles (HW 99, 77 97,95, TX200 etc) so I will explain what I have done.

When the wire is wound & the ends ground the spring is a set length. The spring is then taken to solid (totally compressed) that's scragged. It shrinks the spring a bit. The springs then go for shot peening, the process causes stress relief of the metal (relaxing) so increase length slightly........ The springs are then reheated & compressed to solid again causing the spring to shrink in length again this is double scragging.

So to a certain degree you can pre shrink the spring prior to it going into the rifle or pistol reducing the break in period & subsequent power loss. Some tuners will even fit a new spring & leave the rifle cocked anything from 24hrs to 7 days.

Hope I have explained so you can understand?

[Eidem]

Totally understandable, cheers! One learns something new everyday

[Eidem]

In the last two weeks I have done two FWB300S's and in both cases the piston buffer had totally disintegrated and all that was left of them was dust.

Neil

How was the state of the metal in these?

[LESS THAN FORTUITOUS KENNETH]

Some years ago now, I had a single spring fitted to a 300s. Spring was supplied by a chappie by the name of pok who once frequented this forum. He still might. After fitting, it was running at 8fpe. I found it adequate to do an ft course out to 50 yds. As far as lubricats went, I ran it almost dry.

[u.k.neil]

How was the state of the metal in these?

No damage discernible mate.

Neil