Spring Gun Tuning

[Paul Hudson]

Hi Robert

I found that dropping the power of a 12fpe HW80 down to 10.5fpe and using 7.9g pellets (Mosquitoes) made a huge difference. The rifle was much more tolerant of different holds, simply because it exhibited MUCH less recoil.

Also, putting the action into a heavier stock further reduced recoil. It's the only 80 I've shot that let me keep the crosshairs on the target throughout the firing cycle.

I've since sold the rifle to Adam77K on here, so it might be worth having a word with him...

Paul.

[darren m]

how can you add some weight to your rifle stock with out ruining it .

[rehmk5]

Hi Paul,

Thanks much for your reply. Non-hold sensitive R1 at 10.5 ft/lbs M.E.? Very interesting. And with the factory weight (heavy) piston at that! Imagine!

I had a custom, lightweight piston made for my .177 FWB124 springer (factory piston: 10.5 oz & custom 124 piston: 8.5 oz), and put in a soft tune kit that had 7.9 gr JSB Exact Express 4.52 doing 770 fps (7.9 gr CPLites did 730 fps with same tune due to tighter fit). Hold sensitivity was reduced, but still had about 1" vertical difference between where the groups hit at 40 yds, sitting w/rest vs. standint w/rest.

Do you remember how the R1/hw80 was at 12 ft/lbs ME? I'm not sure I have anything to drop my R1 down to 10.5 ft/lbs, but I do have an old Jim Maccari 13 ft/lb kit I might be able to use to get down to an even 12 or 11 via no spacing.

Again, thanks for your comments.

Robert Hamilton

[Paul Hudson]

Hi Robert.

At a shade under 12fpe it was tooth-jarring

I dropped the power simply by shortening the spring slightly. I also sized the seal for a sliding fit - that is, the piston and seal would slide gently down the cylinder under its own weight, stopping if the transfer port was blocked.

Darren - I fitted it in a Sono Kembang GinB stock which added nicely to the weight.

However, one of my 97Ks sat in a brute of a walnut stock that I added around 5lbs of lead to - and you couldn't tell unless you tried to lift it . The simplest way was to fill a few lengths of 15mm copper water pipe with lead, drill a series of 15mm holes into the end of the stock under the butt pad, then slide the weighted pipes into place.

Paul.

[rehmk5]

Teeth jarring at 12 ft/lbs? Well at about 17 ft/lbs, my R1 has a fast bit of kick. But with it moving groups vertically with differences in hold style, my R1 has been a closet queen.

Thanks for the detune tips.

I've been happy using my TX200's for small pest hunting at local farms/ranches. Got 54 California ground squirrels recently at a local cattle ranch. Rancher was going to poison them out (slow death by internal bleeding...takes 2/3 days to die sometimes), so I did my best to thin his pest population down to the point he doesn't go the poisoning route.

Robert Hamilton
Calif, USA

[Paul Hudson]

Teeth jarring at 12 ft/lbs? Well at about 17 ft/lbs, my R1 has a fast bit of kick.

I found the HW80 to be a bit of an enigma

At 17 to 18fpe they're sweet and smooth; at 12fpe they're "tolerable" but unpleasant. At 10.5fpe they become sweet and smooth again, and a genuine pleasure to use. With the lighter, 7.9g pellets, I was getting the same muzzle velocity as with 8.4g pellets at the higher power, so the trajectory and POI was exactly the same.

Have fun with your tinkering

Paul.

[rehmk5]

Well, thanks for sharing your HW80 experiences Paul.
Much appreciated.
Few in the USA have experience with the lower power levels.
Robert Hamilton, Calif, USA
(now back to reading the news about our idiot politicians)

[Hsing-ee]

If you want to replace a leather washer with a high-quality plastic one, then Jim Maccari sells some which might fit your rifle and they are inexpensive.


http://www.airguns.citymax.com/page/page/251485.htm


Alternatively, T.R.Robb makes PTFE ones which may or may not be an improvement on the original.

http://www.trobb.f9.co.uk/

[chrisarvor]

hi
I havent stipped an airgun down since i used to do my Diana model 16 which was just after the ice age!!!!!
I bought a Boxer spring and new piston seal and breach washer and the washer behind the piston for my old BSA Mercury mk2
I actualy thought they has sent me the wrong piston washer as it wasnt leather!!!!!!!
so i stipped it down and put some wet an dry paper 1000 grade on a broom stick and sprayed WD40 in there and gently cleaned out the air chamber.
When i put i back together i nicked the O ring for the piston so i looked in my o ring box and found a near as dam it one and put it all back together but first washing out the air chamber with some WD 40 . And putting some down the barrel.
Eventualy got the bugger back together without any spring compresser and its superb.Quite a super little gun.
Now i dont understand why your all saying dont use this or clean with that if it works the old fashion way why change it????

[rojin]

Hi Robert

I found that dropping the power of a 12fpe HW80 down to 10.5fpe and using 7.9g pellets (Mosquitoes) made a huge difference. The rifle was much more tolerant of different holds, simply because it exhibited MUCH less recoil.

Also, putting the action into a heavier stock further reduced recoil. It's the only 80 I've shot that let me keep the crosshairs on the target throughout the firing cycle.

I've since sold the rifle to Adam77K on here, so it might be worth having a word with him...

Paul.

Totally,10.5 flbs in a medium to heavy springer is perfect imo. I have a prosport .177 running at 10.8flbs. I made the spring myself from a oteva grade material,bliss to shoot.

[fish4london]

Glad i just read this thread . Just got myself the vmach kit to fit an old Hw 77 and had completely overlooked de-greaser. So many thanks.

[lost?]

great thread, will assist my airsporter rebuild greatly

[Silverfox1307]

I have a BSA Meteor Mk3, I don't have Dry slide/Gun slide or Molykote GN paste, would it be suitable to use a fine wet & dry and polish (or just polish) with Autosol in the compression cylinder plus polishing the piston cylinder and finally coat sparingly with moly grease as suitable plan B ?

[TonyL]

Yep, a caring application of moly grease is more than fine.