Airsporter S low power

[deerwarden]

My Airsporter S is well done on power, I have fitted a new standard spring, O ring, buffer washer and lubed everything, all from Chambers so no dubious parts still only 8.5 pounds up from 6.5. I have put 250 pellets through it but has reached its max, should be possible to get more I'm sure, but having seen a mod on here ref T R Robb removing the buffer washer to long stroke it by the thickness of the washer. Could the piston be put in a lath and a similar amount be taken off the face and radius-ed to do the same thing, i.e, slightly longer stroke. Having read the posts about OX and Titan springs being too harsh on firing don't want to go down that road, however would like to get it up to 11.5, tap is good, but cant remember whether there is enough up the front of the piston to do a similar mod, has anyone removed the buffer washer with no issues etc. Any other tweaks I can do rather than stronger spring, have re-tuned HW 35 HW 77 before so took my time on the BSA, no leaks from tap and using RWS super-domes as advised on here. deerwarden

[Phil Russell]

In my limited experience an Airsporter is happiest at below 11.5, but having said that, 8.5 is a little low.
Areas to look at: Is the piston an easy sliding fit in the cylinder? I have known a new O ring to be a quite tight fit ... in the most recent case I replaced it with a very slightly small diameter one and the piston fit was much better.
Are you sure the tap is Ok: check for leakage at the top: bit of damp tissue over the tap hole as you fire ... a leak will shoot the tissue upwards. Check tap alignment: fire a pellet into some rags and examine it to look for any deformation caused by a slightly misaligned tap. If the tap is parallel sided it can be adjusted by shims.
Check for sideways leaks by applying a little grease to the sides then firing .. a leak will blast a grease film out. I have been told that a too long (strong) spring can cause low power but have not really experimented with this myself.
Good luck
Phil

[pennineway.fswo]

I can't see a mention of calibre

The .22 usually is good for 10-10.5 ft lbs and the .177 - 9 ft lbs

So if yours is a .177, then don't expect too much

Another thing to try is different pellets

The .22 is particularly pellet fussy and likes a 5.6mm pellet, not 5.5mm especially if it has a new or very strong spring
Marksmen make a 5.6mm pellet. J Knibbs sells them. Wasp manufactured by J R are of worse quality than the Marksmen and a very different pellet to the old Eley Wasp
The Marksmen pellets, if sorted using verniers for head and skirt sizes, perform well even at very long ranges but be prepared to spend a bit of time checking them

As Phil says, piston fit is important and also if the gun is harsh to shoot and inaccurate, then there is a good chance that the piston is whacking into the end of the cylinder and not being cushioned at end of its travel by a soft cushion of air

If that is the case take a couple of coils off the spring or fit a weaker one.
A healthy .22 will give 10 ft lbs min and group into 1" at 30 yds with the right pellet but be prepared to experiment a bit
Bisley Practise wadcutters in .22 perform well in my .22 Airsporter S
Good Luck
John

[pennineway.fswo]

Buffer washer mod. - I have tried this on a couple of Airsporters over the years

If you have a good Airsporter, then removing the buffer washer and so increasing the stroke by a few mm will make it even better, but the difference in velocity is not that significant, probably about 10 ft/sec on mine. You need to re-drill the piston head fixing at 90 degrees to the original hole (and nearer the piston ) and make sure that the cocking slot in the piston is long enough (it usually is) to allow the piston to travel about 5-6 extra mm

Pellet alignment can be checked as Phil says shooting into rags, or shooting vertically down into a full bucket full of water with a few rags in
However the best check for alignment is strip the rifle, put a pellet in the tap, close it and then with a plastic rod or a brazing rod push the pellet right through and out of the muzzle. Check the head for bruising If the tap is not correctly aligned/shimmed, then it will be obvious
John