K98 Down Grade

try a different gas ?

i don't know if that would work ill have to go to JD airsoft and have a look as i don't have a chrono at home

What type of gas do you use? At what temperature and which BB weight?

i was using 0.40 with Predator Ultra Gas
what i should have done was chrono it with 0.20

Don't waste your money at any airsoft shop Marsha, most have probably never even SEEN a Tanaka K98, much less worked on one! The only way you can get lower fps with the Tanaka is to use lower powered gas. 134a is the weakest. You can also reduce the tension on the hammer spring. Apart from that, there's not much else you can do that I know of.

I think you could go to a hardware store one of those places that you could buy anything for repairing your home and take the nozzle of the tanaka with you (actually I would take apart the bolt and bring the head of the bolt) and try to find there some tube of the outer diameter of the tanaka nozzle then I would look for a soft wood were after cutting the tube to make a nozzle cut hit it against it with a hammer so wood gets stuck in to it then with a little driller head I would drill the smallest hole I could and try with that and make it bigger after crono if it is under power you can make it bigger

if you don’t have a crono maybe you can use "poor man chrono" use a cocacola can in internet are the instructions for fps reading depending on where you shot the can and the effect of the BB on the can

Ps: better than the wood thing would be filling the nozzle you make with epoxy wait until it is hard and drill it

Don't waste your money at any airsoft shop Marsha, most have probably never even SEEN a Tanaka K98, much less worked on one! The only way you can get lower fps with the Tanaka is to use lower powered gas. 134a is the weakest. You can also reduce the tension on the hammer spring. Apart from that, there's not much else you can do that I know of.

thanks will look into it

I'd try the simple alternative gas charge first as Keith and Pete suggest Marsha, rather than trying to do an irreversible diy mod on the nozzle of very-hard-to-get BGS hop system.

Lowest power option I use is "Duster Gas", like you use for cleaning computer keyboards/parts...

...it's cheep too, you just need the "other" adapter that comes with an AI propane adapter (in the box).

Yup will look into getting a different gas as i dont want the BGS hop touched at all

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134a may no longer be available coz of EU regulations on CFC's but Abbey are now doing a 144a which is basically the same thing but with the nasties taken out. Just thought I'd mention it in case you search for 134a and cant find any.

So how can certain type of gas affect the fps i always thought it was springs that made a differance to fps

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Just think of gas as the spring - different gasses create different pressures when changing from liquid to gaseous state. This also explains why your fps increases as ambient temperature increases, molecules are jiggling about more vigorously in their gaseous state so generating more pressure when released suddenly through a small hole.

Ah i see

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the lowest power gas i've found is butane for re-filling gas cigarette lighters,it has no lube mixed in so a little silicone oil from time to time is needed,dont worry about it being flammable most airsoft gasses are.

bloody hell so some of you guys don't just use airsoft gas, now i'm a total noob on this

Heh, I use(d) cans of propane from B&Q - fitted with an AI adaptor and used with their oil from time to time to lube the seals.
http://www.airsoft-innovations.com/store/ai-gungas-propane-adaptor-kit
http://www.fire-support.co.uk/category.php?cat=267

BTW, don't go down the propane route as it is a powerful gas and you want to reduce power (but it does make gas gun use very cheap)

hang on i'm confused is butane and propane the same?

Both are flammable hydrocarbon gasses but not the same. A bit like peas and broad beans - both legumes but very different.
Wikipedia:
Propane is a three-carbon alkane with the molecular formula C3H8, normally a gas, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel for engines, oxy-gas torches, barbecues, portable stoves, and residential central heating.
A mixture of propane and butane, used mainly as vehicle fuel, is commonly known as liquefied petroleum gas (LPG or LP gas). It may also contain small amounts of propylene and/or butylene. An odorant, such as ethanethiol or thiophene, is added so that people can easily smell the gas in case of a leak.
Butane is a gas with the formula C4H10 that is an alkane with four carbon atoms. The term may refer to either of two structural isomers, n-butane or isobutane (or "methylpropane"), or to a mixture of these isomers. In the IUPAC nomenclature, however, "butane" refers only to the n-butane isomer (which is the isomer with the unbranched structure). Butanes are highly flammable, colorless, easily liquefied gases. The name butane comes from the roots but- (from butyric acid) and -ane.