Spring Gun Tuning

[MishKING]

Have used this excellent guide to tune both my hw99s and my very old mk1 hw80k.

When i tuned the hw80 i used paddy's dry lubricant and sprayed the entire compression chamber and piston and left to dry, i lubed the spring with maccari tar as there was a fair recoil and twang when shot before.

The result after the tune was breath taking! it was almost like i was shooting a different gun the recoil was almost non-existent just a nudge in the shoulder and there was also no spring twang at all! Excellent Although i do have a problem with the rifle running a tad hot (which im in the process of sorting!)

I little background info about my hw99s before i let you know how it shoots after the tune, i brought the rifle about a year and a half ago and it always shot well untill about 4 months ago when it wouldn't group at all. I was seriously thinking about getting rid of the rifle as it shot like a piece of crap and the whole barrel and action was rusted/pitted. After much thought i decided to keep the rifle as i liked the weight of the gun and for the fact that i would of got next to nothing for it second hand. So i thought i would tune it and see where i got!

Right once again i followed this excellent guide and proceded to tuning the gun, all went well if i little bit longer than the tune on the 80 as the 99s is a pain in the bum to strip. Once i had the rifle in pieces i striped and de-greased the internals and again used the dry lubricant on the compression chamber and piston. One thing that i had noticed was the the spring guide was a very good fit for the spring so i decided against using maccari tar on the spring/guide and used some moly grease instead.

I re-assembled the rifle and proceded to a couple of test shots, at this point i was in for a shock as the gun was completly transformed from a twangy dieselling crock to something really special! I honestly cant beleive how nice the hw99s is to shoot now (almost as nice as the 80! but not quite ).

I also know that once i put a tin of pellets thorugh the 80 and 99 the lubes should settle into place and the preformance should get better again.

Heres a tip from a newbie: Wear some bloody gloves when using the macccari tar cause it sticks like sh*t to a blanket!

atb,
Greg

[kash2001]

How do you untune a tuned air rifle ? I know it sounds an odd question but without cutting the spring or ordering a weaker spring, is there a way of de tuning the action.

As once the internals are polished and oil correctly i can't see any way of lowering the power.

If theres no other answer than the above then fine, just interested if theres some thoughts on how it could be done differently.

Cheers
Paul

[99CLOMP]

if the gun has any washers between the rear guide and spring you can remove one or two, if not it may have a front spring guide this can be shortend or removed, or replaced with shorter lighter one, always have a look in side the piston between the front guide and piston front as some tuners will put a washer right at the front,there are lots of ways to reduce power on a tuned gun with out removing the TUNE

[Hsing-ee]

How do you untune a tuned air rifle ? I know it sounds an odd question but without cutting the spring or ordering a weaker spring, is there a way of de tuning the action.

As once the internals are polished and oil correctly i can't see any way of lowering the power.

If theres no other answer than the above then fine, just interested if theres some thoughts on how it could be done differently.

Cheers
Paul

You can increase the dead space in front of the piston by drilling a hole in the piston face but it's a bit radical. Getting a different spring is the easier and more reversible option. You are talking about adjusting the power of the rifle rather than detuning it really, which is what you will need to do everytime the spring needs replacing anyways.

[kash2001]

Thanks for the info guys not being a machinist the easiest route appears to be a weaker spring, or removing the wieghts if there are any a big help many thanks for that at least there are a few options

Thanks
Paul

[LukeB]

Quick question re: IPA. There is some varnish on the blueing on the outside of the chamber on my FWB Sport where a previous owner has re-varnished the stock with the action still in place. Will the IPA remove the varnish do you think? I am guessing that the IPA won't react with the blueing in anyway and damage it???