FWB 300 tuning

[Creakingjoints]

Seems to be a re-curing question and most people don't recommend it but I gave it a go with not bad results. Firstly, if you buy a 300, I suggest you buy from a club if possible; probably much better maintenance than my acquisition. Aesthetically the old lady looked ok for it's age, but firing it was an eye opener. Accuracy was pretty good , but sounded hellish. Stripdown revealed all :-
Essentially the gun had been trashed. The two minute tune up of the new port seal was there, but the old buffer was still in place and the springs were a joke. Not the contra-wound style of originals, but two same wind springs. The bolt which locks the compression chamber to the action was well chewed, a suspect spacer/washer was in place and a couple of missing e clips.

A strip down, clean and re-lube, new port seal and buffer, new piston ring and a one piece mainspring 9.5ft/lbs from Metura were fitted and tried. Accuracy was improved, but the action although still light in cocking, still sounded twangy. Noticeable power increase. Sledge action re-setting to "battery" quite a bit.
Tried again with mainspring (12 ft/lbs) from Waffencentre Gotha and a distinct improvement all round. Accuracy much better, no twanging, proper sledge action, smoother shooting and very little increase in cocking effort.

Being a mediocre shot at best of times, I won't say too much on the subject of accuracy, but five pence piece at 15m readily achieved.
Power :- Having got rid of my Chrono, I used the tried and tested 12mm marine ply at point blank. As purchased, 8gr pellet would just lose it's head in the ply.
Metura spring sees slight lifting of the other side of the ply and Waffencentre Gotha spring just shoots through. I now have a pretty handy piece of kit, so don't be afraid to try.

[Steve Valentine]

The "tried and tested 12mm marine ply method"?

[Peter Dunkley]

Marine ply and LUBE scare me. Gun should shoot at around 6ftlbs and run dry. I know some have upped it to around 8 but there is a penalty.

[Geezer]

I would be very very happy to be proved wrong, but I just don't see how you get more than 8-9 ft/lbs out of an LG300 without forced dieselling or some kind of total re-engineering of the internals that goes way beyond a new spring. There just isn't the swept volume, surely?

If you can do it, you've just massively reduced the values of the Whiscombe, Park, Diana 54 and SR200, by creating arguably the world's best ever minimal/no-recoil springer. (And I'll have one, thank you.)

[Peter Dunkley]

Whilst surfing I came across an American shooting forum where a couple of guys upped the power on these guns to shoot ground squirrels at close range.
After much stripping and spring testing they came to the conclusion, "and these guys knew their stuff" that 8ftlbs was max without altering the whole characteristic of the gun.

[rockdrill]

Marine ply and LUBE scare me. Gun should shoot at around 6ftlbs and run dry. I know some have upped it to around 8 but there is a penalty.

While I know they are recommended to run dry, I have noticed that doing so tends to give a firing cycle that is audibly more twangy that a Duane Eddy guitar solo.

I have found thagiveing the springs a light coating of either dry moly spray or a similarly light coating of Rocol Moly Paste kills the twang and makes for a very consistent and sweeter firing cycle.

The design as it stands has the ability to make a little bit more power than 6ft.lbs simply by changing the main spring, although personally I would not push it over 7.5ft.lbs - this albeit relatively small increase does make for a very nice longer range shooter, even capable of consistently dropping field targets out to 55 yards.

[little.O]

had my 300s for about 14 years.I bought it from a guy who had quit shooting but had taken the gun to city air weapons (Coventry) for service regularly.I stripped it a few months ago and found all standard looking parts in it and it was just about bone dry.Ichecked in the manual and it said one drop of oil on each side of piston ring,and one drop on each major component and onr drop on each pin of the cocking link.The springs were not supposed to have any thing done to them at all. So I did as it said and re-assembled it.It still works perfectly and puts out about 5 lbs/ft using R10 pellets.I would not tune it for power for all the tea in China. I cannot understand why poeple take abeautifully engineered rifle design for a precision shooting sport and try to make it "better".Buy a gun for the job you want to do and leave the increasingly rare excellent rifles for 10m.They're not supposed to shoot any further.
Mine will survive at least as long as I do!

All the best, Owen

[rockdrill]

I can't speak for anyone else, but I have done it because the design is over-engineered and can handle the small increase without being stressed.

In the 10m arena these are old guns that seem to be relegated to being used as introductory level club guns and based on some examples I have come across are not given the level of care they should have.

Yes it bis a beautifully engineered design, but when you shoot one and sounds like a box of spanners being shaken it rather detracts from the pleasure of shooting it. Adding just a small dab of modern lubricant sweetens the firing cycle without affecting the performance. With this treatment my 300's will also outlive me so what is the problem?

[Creakingjoints]

As stated in original post, this is a question that pops up from time to time and I gave the results of my experiment. Power testing with "tried and tested 12mm marine ply is actually a joke if your sense of humour needs prompting. The gun still has to be chrono'd but with little effort, I got a smooth shooting reasonably powerful weapon ( reckon 10.5/11 ft lbs. which could be used for hunting or field target. It's accuracy will probably be far better than I can achieve. The end result in no way suggests it would be the disaster some have predicted; the inherent build quality ensures that. As for the lube question, Dry-Slide equivalent Ambersil applied to the compression chamber and buffed rigorously ( piston un - touched) and moly grease sparingly on the mainspring and that was it. A simple spring change means this old lady can be brought back to original sec. at any time. so where's the harm?