Spring Gun Tuning

[rehmk5]

Pardon the slight change of subject from strictly tuning, but I can't start a new thread.

Got a HW80/Beeman R1 question if you would:

Anyone have a 12 ft/lb HW80?

I have a FAC R1 (am here in Calif, USA) that does 7.9 gr Crosman Premier Lites about 1,010 fps.

Problem is, that though it groups accurately, it is hold sensitive in that if I switch from shooting standing with a rest, to sitting with a rest (artillery hold used both), the nice and tight groups move vertically.

At about 35 yds, my sitting with rest groups hit about 1.5 inches higher than my standing w/rest groups.

Can anyone comment on how a 12 ft/lb HW80 is about allowing different holds without the groups moving up/down?

Power is nice, but accuracy is better.

I'd get a 12 ft/lb kit for my Beeman R1 if that would make it more like my AA TX200 (which hits the mark, no matter how I hold it. Dittos for my Beeman R7 and HW55s).

Oddly enough, my Beeman R9 is more tolerant of varying the way I hold it and does not shift the groups like my R1.

Thanks, and good luck on keeping your airgun freedoms. Here in the USA we have the "Democratic" Party that would strip us of our firearms, airguns, water pistols, sharpened pencils, etc if they got the chance.

Robert Hamilton
California, USA

[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.

[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/

[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.