Spring Gun Tuning

[Snooper601]

Back in the eighties Cardew recommended popping [hw] spring-guide into piston as a simple way to add weight and a home-turned tophat at the breech end with thrust bearings on both parts to ease spring torque dynamics.regaRDS torville.

It's the other way round!

Top hat shaped guide in the piston, short and light.
Long spring guide at the rear end, breech, ideally fixed to the trigger block to save damage to the rear block by rotational forces. Non moving part so weight is unimportant, meaning it can be long enough to almost touch the top hat when the spring is fully compressed.

Cheers

John

[leon1935]

I have a 1919 BSA Standard .22

Would the tuning guide apply to a gun of this age.

It is surprisingly accurate to about 30ish yards, further than that it is me...and Iron sights..

Leon

[Hsing-ee]

I have a 1919 BSA Standard .22

Would the tuning guide apply to a gun of this age.

It is surprisingly accurate to about 30ish yards, further than that it is me...and Iron sights..

Leon

Ideal for a BSA like that, although the parts should need very little polishing after all that use! You might need to buy or make a new piston washer from leather, or you could possibly get an adaptor for a plastic parachute washer. Have fun.

[torville]

This is a term coined by the late ,great gerald cardew,airgun boffin of the seventies and particularly interested in the [v-rok] mod.35 export with it's leather wasjer-;card reckoned that the piston washer,reciprocating back and forth is intended to scrape some lube i.e.whatever petro-chemical oil/grease is present in the action and either prepped on n/cylinder walls or emerging from "fuel store" on spring which he recommended as three teaspoonfuls two-thirds up mainspring ,"fuelglobule" nestling inside piston and a piston sleeve/grease shield to prevent too much flying off thru cocking slot onto walls of n/cylinder and from there scraped forward in front of piston with each shot and this scraped fuel righteously detonating in the diesel phase .
our experiments with the [v-rok] mod.80 show that with no lube there is only a popgun phase;with too much finding it's way in front of piston result erratic vel. and interestingly some diesel giving high reading but most excessive detonation/diesel remarkably hampering downrange performance with low vel.resulting.
our verdict that with modern [v-rok] piston without open cocking slot where grease can get flung thru there can be no call whatever for piston sleeve of thin stainless which would be superfluous but certainly have heard of ptfe/synthetic sleeve which might well reduce mechanical noise but any grease shield function redundant due to all grease being confined inside piston of modern [v-rok] pattern .
ideal fuelling we reckon is one drop of ramsbottom[sm50]via t/port ( allow cocked gun to stand a few hours) every three tins pell )note: first shots after fuelling use two heavy pell each time for a coupla loads until any excessive smoking dies away)and on rebuild smear of [abbey LT2] on area where piston washer meets piston so it remains in this slight groove also [moly paste] on skirt of piston and some on upper rear of n/cylinder cos piston gats pushed upwards as wellas backward on cocking and thus bears on this upper surface of n/cyl at rear action plus of cours an amount of grease on mainspring to lube coils but not so much to reduce efficiency in effort to dampen mechanical noise.regards.

[Hsing-ee]

This is a term coined by the late ,great gerald cardew,airgun boffin of the seventies and particularly interested in the [v-rok] mod.35 export with it's leather wasjer-;card reckoned that the piston washer,reciprocating back and forth is intended to scrape some lube i.e.whatever petro-chemical oil/grease is present in the action and either prepped on n/cylinder walls or emerging from "fuel store" on spring which he recommended as three teaspoonfuls two-thirds up mainspring ,"fuelglobule" nestling inside piston and a piston sleeve/grease shield to prevent too much flying off thru cocking slot onto walls of n/cylinder and from there scraped forward in front of piston with each shot and this scraped fuel righteously detonating in the diesel phase .
our experiments with the [v-rok] mod.80 show that with no lube there is only a popgun phase;with too much finding it's way in front of piston result erratic vel. and interestingly some diesel giving high reading but most excessive detonation/diesel remarkably hampering downrange performance with low vel.resulting.
our verdict that with modern [v-rok] piston without open cocking slot where grease can get flung thru there can be no call whatever for piston sleeve of thin stainless which would be superfluous but certainly have heard of ptfe/synthetic sleeve which might well reduce mechanical noise but any grease shield function redundant due to all grease being confined inside piston of modern [v-rok] pattern .
ideal fuelling we reckon is one drop of ramsbottom[sm50]via t/port ( allow cocked gun to stand a few hours) every three tins pell )note: first shots after fuelling use two heavy pell each time for a coupla loads until any excessive smoking dies away)and on rebuild smear of [abbey LT2] on area where piston washer meets piston so it remains in this slight groove also [moly paste] on skirt of piston and some on upper rear of n/cylinder cos piston gats pushed upwards as wellas backward on cocking and thus bears on this upper surface of n/cyl at rear action plus of cours an amount of grease on mainspring to lube coils but not so much to reduce efficiency in effort to dampen mechanical noise.regards.

I think that is too much lube; Cardew's experiments were fine on the leather-washer out-of-true-cylinder guns of the time, but modern rifles work well in the pop-gun phase and do not NEED the boost from 'fuel'. If you over-lube with a drop of SM50 every 1500 shots you will get diesel shots and inconsistency generally, weakening the spring and losing accuracy. The combustion theory is a controversial one, even during Cardews heyday - in 1981 there was an experiment with a DRY lubricated FWB Sport which made a healthy 11 ft lbs. Note this rifle had a plastic parachute seal and the legendary FWB cylinder which is made to extremely close tolerances.

[sniper24687066]

I might just give this a go,many thanks for all the info.