15 replies to this topic

[raygun]

Hi Pritu,
Welcome to the Forum.

Are you sure that the prefix is GP because I can't find such a one. It may be that it's just me

You won't be able to fit a Ram to the Airsporter as the piston has a central rod for latching the trigger.

This site may be of help to you.
http://www.chambersg...s.co.uk/bsa.htm

I don't know if there would be problems sending to India though.

ATB
Ray.

[bulsaye]

I can find reference to a a GF model, and it's possible your P is actually a distorted F? If so, it's a mk 2 model in .22 made from June 67 to July 1968. Airsporters thru the mk 3 featured the cone nosed piston or taper nosed piston (same thing). These are basically sub 12 ft/lbs guns that even when very carefully and professionally tuned *might* see slightly above 12 ft/lbs, but it's not a good candidate for high power tuning. RB

[The Green Man]

http://www.airgunfor...6160&hl=stutzen

Can anyone help me with this dating?

[raygun]

http://www.airgunfor...6160&hl=stutzen

Can anyone help me with this dating?

The only info I've got is as follows:

Mercury .22, ZT Stutz, 92 - 2000.

Hope this helps a bit

ATB
Ray.

[The Green Man]

92 - 2000 hmmm, that narrows it down!

Thanks Ray (and I'm missing her already )

[raygun]

Hi Pritu,
I think the age/model was answered in post 4.

When you re-fit the maxi-rail make sure there are no burrs on any of the "slots" or "keys".

ATB
Ray.

[Artfull-Bodger]

Hello Pritu, if your sporter has a maxi grip scope rail mounted on top of the cylinder that makes it a later model, probably a Mk6 or 7, these rifles respond really well to a tune up, one mod I do is to make a new piston head with a webley type seal in place of the o-ring! take care with the tap too, its fit is critical to the rifles accuracy!

[bulsaye]

Seems my old Hiller book doesn't go to the GP serial number listings, so it's entirely possible it's a mk 6 or higher. Yes- the flat faced pistons will make more power, with the RB2 version being the best candidate for power tuning to the max. Come to think of it, I need a piston bumper ring/washer for my own Airsporter (the absorbtion ring behind the piston head). On older guns, these bumpers decay and crumble. Hmmm.. need one for my old Mercury as well! RB

Edited by bulsaye, 01 July 2007 - 03:03 AM.

[Artfull-Bodger]

Hi Pritu, the mod to the piston head is a replacement job, I have a lathe here at home and do my own modifications, the Airsporter piston head is removed and a new design of the same length was turned up on the lathe but with a different profile that takes a webley style seal (reffered to as a parachute seal) made out of softish nylon (dont recall the actual material now , softer than nylon 66 though?).

with a new spring, the piston head and spring guide mine produced 15 odd ft/lbs and I had to take a coil and a half off the spring to bring it down to UK legal (12ft/lbs) the redesigned piston head made a big difference to the firing cycle but is a lot of work if you have no engineering background!

as the rifle has a tap loading breech the best way you are going to clean the lead out is with a rifle brush followed by felt cleaning pellets!

[Artfull-Bodger]

the stroke length stays the same as you make the new head to the same dimensions (seal fitted) as the original, the seal I used was custom made copying a webley vulcan seal I had in the spares box but to the dimensions of the airsporter tube size (i seem to recall 27mm), I made the first one out of delrin but this was too hard and led to poor sealing and a harsh cycle, I contacted a local engineering plastics supplier and spoke to thier technical department who reccomended a soft nylon that exhibited reasonable wear and low friction .

for the life of me I cannot recall what the acual plastic was called, its one of the nylon machinable plastics, I'm sure theres a local supplier who could put you on the right path, just tell them nylon 66 is too hard and see what they reccomend, the actual rod was reasonably cheap so you can experiment!

regards
Mike.