Idiots guide to classic airgun strips (pt 1)

[Phil Russell]

ASI STATICAL STRIP

A cosmetically fair .22 Statical was in dire need of internal attention: pushing out between 70 and 100fps with Superdomes. The breech seal was clearly a bit tired but I had a surprise when I removed it: it was about 1cm deep. I simply shimmed the inside to raise the outer lip just above the breech. Power rose immediately to around 200fps. But the cocking stroke was too easy ...
To strip:
1. Remove forend woodwork, 2 bolts. Remove trigger guard, 1 bolt.
2. Remove action from the butt and crackle finish outer housing: 4 small cheesehead bolts on the underside.
3. It is now best to remove the rear sight, noting how it all fits together.
4. Note 2 sliding bridges on the action: one near the trigger the other near the breech. On our model the sliding bridge near the breech had a small spring on each of the 'slide rods' but I have heard recently of a model (possibly a later version) that did not have these but had O rings.There is no need to touch the breech one unless you really want to strip that unit as well.
5. Remove the saddle bridge near the trigger housing by removing 2 circlips on each of the 4mm sliding rods. Push rods out of the way and remove the saddle, sliding it off the anti-bear trap bar that extends from the cocking lever. On the 'other model' mentioned above it appears there was an extra small spring here to drive the recoil mechanism.
6. Remove 2 pins holding trigger housing in place. Look inside the housing and note that the pins have a knurled end. Drive pins out knurled end first. Trigger housing can now be pulled away but it may be tight.
7. The mainspring is next. I advise using a spring compressor. With a suitable tool (a bit of dowel?) inserted in the end of the cylinder, take up the strain on the end block and undo the 6mm hex bolt holding the saddle slide arm bracket to the action. Remove.
8. Slowly release tension on spring as it pushes the end block out. Remove end block and spring. There is a free floating spring guide.
9. The piston can be removed by simply lifting the cocking arm out of its slot: no need to discontent anything from the action.
10. The piston washer is a standard leather one. This one was fair ... a not tight fit in the cylinder with the piston falling slowly under its own weight but almost stopping when I put a thumb over the muzzle. A new washer could easily be made.

The spring fitted to the test rifle was 31 coils of 3mm wire (93mm total space) and was very weak: it was almost possible to compress it by hand.
I replaced it with 29 coils of a Webley Tracker spring, 3.2mm (92.8mm space). I tried a few modifications such as a fixed spring guide but found the 93mm measurement critical. Exceed it and the rifle does not cock. In the end I stayed with the floating spring guide and a 29 coil spring.

Reassembly is a reverse of the above. Fit piston and spring with spring guide inserted. Then fit the end block. Use the pusher tool to push the end block into the action and compress the spring until the 6mm hex bolt hole lines up with the hole in the action. Refit saddle and 6mm bolt.
Remove tool and refit trigger unit, making sure the pins are fitted the way they came out with the knurled part last to be tapped home.
Refit the cocking arm into the piston slot.
Refit sliding bridge, making sure the anti-bear trap arm fits inside the bridge. Slide the pins into place and secure with the 4 circlips. Check that the bridge slides freely.
Refit action to stock. This can be a little fiddly. Look at the underside of the action and note some raised pimples on each sliding bridge. These locate in small holes in the crackle finish housing. I found it easiest to locate the pimples at the breech end first; the rifle has to be at just the right angle and spacing in order for the action to slot into place. Persevere and it will suddenly click. Replace the 4 small bolts to secure the action. Replace trigger guard and forend woodwork. Replace rear sight.
Once completed and relubed, the test rifle was running at around 450fps with .22 Superdomes for approx 6.5ftlbs. The F in Pentagon mark indicates 7.5 Joules (5.5 ftlbs) for countries that have this lower restriction so I do not think this is too bad.
Cheers, Phil