Spring gun tuning for good shooting

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Longshot
Posts: 19
Joined: Wed Dec 02, 2015 6:27 pm

Spring gun tuning for good shooting

Mon Dec 28, 2015 5:29 pm

Hello all this is a general question for you tuners out there I am tuning my springer as it got a bit naughty ( dieseling ) plus with the existing spring guide set there was not much to reduce the length & thus preload . Now I had another spring & guide set that was about an inch shorter total length Q is where to add the preload & what material to use where as i have both steel washers & plastic .
In the original setup there was two steel washer in the piston end thus adding weight to the piston So I could have replaced those with plastic saving around 60grn of mass from the piston likwise in the new shorter spring pack .

So the BIG question is Will reducing the piston weight make it shoot better or not taking into consideration the preload might need to be increased to get power set to around 625 fps with Falcon accuracy plus. Or add the weight in the piston & reduce preload .

Your thoughts please
Regards longshot

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Blackbaronfish
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Re: Spring gun tuning for good shooting

Mon Dec 28, 2015 7:24 pm

I know the tuners are favouring lighter pistons at the minute with out opening ports.

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Sake-san
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Re: Spring gun tuning for good shooting

Mon Dec 28, 2015 7:57 pm

To be able to try and assist you it would help to know what the gun actually is, what is the spec of the new spring & guides, am assuming .22 given the fps, is it bouncing or slamming (how does the ft/lbs change with lighter / heavier pellets)?
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gary martin
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Re: Spring gun tuning for good shooting

Mon Dec 28, 2015 8:27 pm

piston weight. will it make a difference? yes, but good or bad? reducing the piston weight will reduce the power output, it will accelerate faster, but the piston will slow down faster when it gets to the compressed air. in general the feel will be a better, smoother shot cycle. to combat this you require more spring. if the piston is too light, you will get piston bounce(not good) transfer port would need to be opened. what rifle do you own, and what do you not like about the firing cycle. thing is it's personal, what i like, you may not. if you can shoot a retuned rifle which you like, replicate it. i like a light piston, others like a bit more weight. many things need to be considered. a little more info is required. ATB Gary.

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Longshot
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Re: Spring gun tuning for good shooting

Mon Dec 28, 2015 8:43 pm

Hi Everyone and thanks for the reply's
Gun is a Webley Longbow .22 with some degree of tuning already done ie Plastic top hat & guides plus a liner inside piston so no twang at all just nice pop on firing .std port

As I have left things tonight I shot a card with the steel in the piston earlier . Then took out the steel and replaced with as much plastic as I could to get it to cock & tested to 619 fps with around 17mm preload at the breech block.

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gary martin
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Joined: Thu Feb 19, 2015 8:21 pm

Re: Spring gun tuning for good shooting

Tue Dec 29, 2015 8:57 pm

Longshot wrote:Hi Everyone and thanks for the reply's
Gun is a Webley Longbow .22 with some degree of tuning already done ie Plastic top hat & guides plus a liner inside piston so no twang at all just nice pop on firing .std port

As I have left things tonight I shot a card with the steel in the piston earlier . Then took out the steel and replaced with as much plastic as I could to get it to cock & tested to 619 fps with around 17mm preload at the breech block.



could i ask, by removing the steel from piston saves is that 60 grain or gram? 60 grain would not yield much difference, 60 grams would!
the way i prefer a rifle is lighter piston, helps give a snappier feel. heavier piston gives a lazy feel, but happens over a longer duration. all depends on how you like it. also could i ask whats the significance of 625fps? if the rifle happens to be easier to shoot 20fps lower, IMHO thats a better way to go. if you miss the target faster, you still miss! accuracy is everything at the power levels we have.
Gary.

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Longshot
Posts: 19
Joined: Wed Dec 02, 2015 6:27 pm

Re: Spring gun tuning for good shooting

Wed Dec 30, 2015 9:04 pm

gary martin wrote:
Longshot wrote:Hi Everyone and thanks for the reply's
Gun is a Webley Longbow .22 with some degree of tuning already done ie Plastic top hat & guides plus a liner inside piston so no twang at all just nice pop on firing .std port

As I have left things tonight I shot a card with the steel in the piston earlier . Then took out the steel and replaced with as much plastic as I could to get it to cock & tested to 619 fps with around 17mm preload at the breech block.



could i ask, by removing the steel from piston saves is that 60 grain or gram? 60 grain would not yield much difference, 60 grams would!
the way i prefer a rifle is lighter piston, helps give a snappier feel. heavier piston gives a lazy feel, but happens over a longer duration. all depends on how you like it. also could i ask whats the significance of 625fps? if the rifle happens to be easier to shoot 20fps lower, IMHO thats a better way to go. if you miss the target faster, you still miss! accuracy is everything at the power levels we have.
Gary.

Hi Gary
60 grains or 2 tuning washers as there was one holding the liner in piston then one between top hat & spring , bear in mind this gun was well over ( having adjusted for pellet weight in the chairgun program ) at 13.15 . Now around 11.4 or so , power is now easier to adjust with the shorter spring so I can set it lower . The washers lost around 15 to 20 fps .
Lots of input on forums some saying lose around 25 gram from piston the add 6mm stroke . I am just after the best setting for the STD piston at the moment .
The gun is still quit snappy at this point so I am wondering if losing the top hat but adding a steel or plastic washer between spring & Liner will alter it much .

The current setting produced this group sitting on a Swivel office chair shooting out of the bedroom window using a 3 x 9 40 scope on 8 x zoom , now I am not sure if it's good or bad but its clearly working to some extent . TBH the blue section is half obscured by the mill dot & the last two outside were my last two & losing control.

The same target at zero range of 21 yds was much tighter easily within the Black circle to top left . The pellets to the left were me aiming at the black circle to get hold off with both Falcon & AA field

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