Idiots guide to classic airgun strips (pt 1)

[Garvin]

Paratrooper exploded view

Trigger detail

[Phil Russell]

Again maybe not quite a collectable but it is an old favourite and I note some forum members asking for advice at times. So here are some notes on the strip:

This guide gives instructions on how to strip the HW77 / 97 standard and Karbine versions. It does not contain information on tuning nor of stripping the Rekord trigger unit.

Tools required: 3mm punches (2), light hammer for punches, blade gunsmith screwdrivers to fit stock screws and trigger guard screws (no cross head screws), small adjustable spanner or spanner to fit the action retaining bolt..

Stripping:
Remove any telescopic sight and any rear sight.
Remove action from stock (2 x 5mm screws at the forend plus their retaining washers and 2 screws in the trigger guard). Remove trigger guard.
Lift action from stock.

Place action in a padded vice, barrel to the left and trigger uppermost.

Note the large threaded nut to the left of the trigger block. Undo and remove using the small adjustable spanner, taking care not to lose any spacing washers if they are loose. The anti-bear trap / safety slide is now free but held by the underlever.

Tap out the two pins that hold the trigger unit in place. I tap from front to back. The pins are of different lengths, a shorter top one near the end of the trigger block and a longer bottom one nearer the breech. Remove the trigger housing by tilting the trigger housing up and to the right. As you do this, keep a hand over the safety catch to prevent it pinging out. When the trigger unit is free, remove the safety slide plus its spring.

Remove the pin that holds the underlever in place on the breech and remove the underlever, raising it to disengage the end that goes into the compression cylinder slot. If you take care you need not knock the pin all the way out.
NOTE: if you are only replacing the spring and do not want to get at the compression cylinder and piston, you do not need to remove the underlever.

You now need to remove the end block that housed the trigger unit. The preload from the spring is not great but I advise wearing goggles and a glove on the hand you unscrew the block with.

Unscrew the block. It may be stiff to start, so you can place a lever in the trigger housing slot to start the movement. I use a piece of timber about 6” long. Take care as you unscrew the block, keeping watch on the screw threads. The block will suddenly lose the threads, so be prepared to support it with the gloved hand. Place the block on one side. The spring and spring guide can now be pulled out. If you removed the underlever, you can also now pull out the compression cylinder and piston assembly.

You can now service any parts you wish but at the least I recommend a clean of all parts and reassembly with fresh lubricant. I also fit a piston sleeve as a matter of course.
Next post: the rebuild
Cheers, Phil

[Phil Russell]

HW77 / 97 rebuild
Re-assembly:
This is basically a reversal of the above.
Begin by assembling the piston in the compression tube (remember suitable lubrication), making sure that the underlever slot in the piston lines up with the square hole in the compression tube. Fit this assembly into the action with the piston slot uppermost, in line with the underlever slot in the main action.

Refit the spring and spring guide, correctly lubricated, into the piston.

Now you need to refit the end block. With the block in your gloved hand, push against the end of the spring guide to bring the block up to the main cylinder. Turn the block to engage the threads. This is easiest done by pushing with the gloved hand and turning the block with the other. Screw the block into the action, taking care to look at the square hole in the cylinder and the slot in the piston to make sure they are not going out of alignment with the slot in the action. They can easily do so, but to stop or correct any movement I find it easy to hold a screwdriver in the slots to prevent the piston cylinder and piston tube from rotating. When you have screwed the end block in as far as you can by hand you may well need to apply some leverage to get it up tight. You can check this position by noting that the sides of the trigger housing slot line up with the action and the threaded bolt can be screwed into the block.

I now prefer to refit the underlever. Place the safety slide / antibear trap slide mechanism on top of the action and refit the underlever cocking arm end into the square hole and piston slot. Refit the underlever into the pivot at the end of the action and tap the pin home.

You can now secure the safety slide to the end of the action with the threaded bolt. Ensure the spacing washer is still in place. You need to push the safety slide a little against its spring pressure but it is easily done; refit the threaded bolt. Once fitted, just release the underlever and make sure the safety slide moves freely.

Now to refit the trigger. Refit the safety catch, remembering to put the spring on the catch before you push it through its locating hole in the end of the action. Hold the trigger unit with the left side slightly up and feed the trigger unit into the trigger housing, all the time keeping the safety catch pushed in against its spring. As you feed the trigger unit home, bottom right corner first, rotate the left edge down a little and it will fall easily into place. When the unit is seated, take two punches and place them through the holes in the action from the front to back, all the time holding the safety catch in. Then take the shorter pin and replace it through the action and trigger unit from the back towards the front. This will drive the punch out; the pin should go in quite easily. If it jams or refuses to go, do not force it; you will have the holes slightly out of alignment. Jiggle the punch to bring the holes into alignment.
Fit the long pin.

Make sure the captive nut at the top right of the trigger unit is in place ... a trigger guard screw fastens into this.

Refit action into the stock. Refit trigger guard. Job done. Refit sights and test rifle.
Cheers, Phil