Bsa airsporter mk6 rebuild

[philip gowers]

Can anybody helpme. I have a airsporter mk6. I want to put a new spring and seal in. I have striped it down.It is the piston with the metal head not aluminium and an o ring seal. I want to know,which is the best spring to put in it, to put it between 11 and 12 foot lb. I have seen fancy kits with alot of messing about but they will take it over and i dontwant this.Also I want to smooth it out on recoil. Is there any seals in the pellet port. Any help will be a great help thanks in advance. Phil.

[pennineway.fswo]

These rifles give less than 10 ftlbs in .177 and about 10.5 in .22

Over-springing the rifle to get more power usually makes the gun inaccurate and nasty to shoot

Just use the standard spring for the job

The piston heads are normally aluminium on later models and nylon on earlier models
If yours is metal but not aluminium then it is probably an after-market steel one that can be purchased to up the power by increasing the weight of the piston. I have not found them to make much of an improvement.

Sizing the O-ring can save a lot of running in time and help get the power around 10.5 ftlbs in .22

Do not be tempted to put in a square section spring, the gun will not appreciate it

There are no seals in the loading tap and these taps do leak a bit, but there is little you can do about that.
Good luck with the rebuild
ATB
John

[philip gowers]

Thank you very much for your help. It is most welcome. By the way it did have a square spring in, which made it feel like a cannon. Could you please tell me what you mean by sizing in though, thanks so much phil.

[pennineway.fswo]

Hi Phil
A new Airsporter 'O' ring is usually a bit tight in the cylinder and the piston may be difficult to push down the cylinder. This friction uses up quite a bit of power.(2 or 3 ftlbs loss is not unusual)

Ideally you should be able to push the piston along the cylinder bore quite easily.
By using a slightly smaller diameter '0' ring you can often get a better fit and the rifle will give more power. Another way round this is to fit the standard 'O' ring on the piston and then use 1000/1200 grade emery paper on the 'O' ring to reduce the diameter slightly, checking the fit until you are happy that it is not too tight.
If you get this right you can then sometimes shorten the spring by a couple of coils or so to make cocking easier and to make the gun nicer to shoot without loss of power. You will need access to a chrono to confirm power

Airsporters, like other air rifles with loading taps do not like powerful springs due to the high lost volume in the loading tap area.
All that happens on firing is that the piston slams into the end of the cylinder and this can damage the gun.
A full length square section spring in an Airsporter can turn a good airgun into a waste of space

Try and achieve a nice, accurate 10 to 11 ftlb rifle (if .22) rather than one that kicks like a mule and is inaccurate.

Use the moly grease sparingly on the piston ring and a bit more liberally on the spring
ATB
John

[joffy]

my airsporter s in .177 puts out 11.5 ft/lbs with superdomes

[jdwynn1976]

As peninesway said around 10.5 ft lbs is about right in .22 without it getting nasty

go for a standard spring ( i also pulled a square section job out of mine when i got it). Chambers do one that seems nice and consistent.

Enjoy your project

j

[philip gowers]

Hi John,
Thanks for all the advise on my airsporter, she is now finished, looking and shooting like a brandnew gun.It is putting out around 10lb at the moment as im only using it for targets. It is fine for me. For my first collector it has been nice and enjoyable getting this back to its proper condition. thank you again, im now looking for anew project! phil