airsporter mk1 spring length

[wild boar]

i got a mk1 airsporter and took the spring out - it was a bit bent so i got a titan one i know i should cut some off it but of course i tried it full , it took some pushing in but power went down by 30fps with it full length and but it sounded real powerfull , i know lots of people will have done this so i am asking - what have people found the optimum length for cutting these for the airsporter ? i dont want to cut too much off and spoil it , i am not sure how it could be less powerfull with the stronger spring - perhaps it expands less fast when its too compressed ?

[MattyBoy]

IMO the Titan springs are too stiff for the relatively delicate Airsporter.

I have a feeling that the OEM spec spring from Chambers would be better.

I can't advise on how many coils to cut off the titan but Mick T20 is a good man to ask for advice on this sort of issue.

Matty

[Phil Russell]

Being over-sprung is a reality and I suspect you have just discovered it (again). In such situations what you could do is take it step by step and reduce it slowly coil by coil, not forgetting to finish the cut end as you go. I am not aware of a simple formula to say 'cut X coils off and all will be well'. To have a lesser effect than removing a coil, try collapsing a coil instead. You may, however, get a feeling for it by considering how difficult it is to refit the trigger block. If there is a lot of spring sticking out from the cylinder and you develop a hernia trying to fit the trigger block, then you will almost certainly have too much preload. Find the length of a standard (non Titan) mainspring from the database on here. As Titans are invariably stronger springs, do not try a length longer than the standard; indeed your start point could by a coil less. ..... but I cannot take responsibility for you getting it wrong ... just go slowly, bit at a time.
It is assumed that everything else is fine with the rifle ....
Cheers, Phil

[wild boar]

yes i am going to chop links off it and see but of course when i find i chopped one too many off its too late , i might get some threaded bar and measure the compression of each if i have time , but i think i will end up with the standard length and if the titan is a slightly stronger type spring then i will still have an improvement .

[Phil Russell]

yes i am going to chop links off it and see but of course when i find i chopped one too many off its too late , .

Not necessarily, and I doubt if you will. But if you chop and find you are lower than you want you can always add a preload washer / slip bearing. If you have been able to cock and fire with a longer spring then you will not get coil bound with a mm or two of preload washers.
Cheers, Phil

[wild boar]

impatience took hold of me and i just cut it off and bent the end down to be flat so now its just 1/4 inch longer than the one i took out so i can try in now

[MattyBoy]

Will be interesting to see the result.

Matty

[wild boar]

first few shots - (with old spring 530ish ) first shot- 535, then 553 591, 584 then chrono started to play up as usual but i think it will settle to be a bit better with the new shorter spring , around 600 would be perfect . gonna let it bed in then re-test it , its not bad to cock and fires sharp but not vibraty (if thats a word)
i used krytox grease , its expensive but i only used a small ammount over the internals and leather washer, dont think this grease diesels at all.

[wild boar]

took it out and 6 shots - 590 586 577 597 575 585 with marksman i am happy with this as it might settle a little lower and it doesent sound harsh to fire

[MattyBoy]

Have you any original 5.6mm Eley Wasp?

They might be more efficient still.

Matty