Idiots guide to classic airgun strips (pt 1)

[ggggr]

I have just found this on Chambers Website, which might help.https://www.gunspares.co.uk/products/24464/G71/ . I bought this recently to have a look at one. Unfortunately, the safety catch is missing although the gubbins are there on the inside. This came with a missing medallion, none original stock screws and the stock had broken at the fore end at some point and been repaired. This is more or less a G 78/79 with a different trigger and a barrel sleeve. The sleeve on mine will turn (I am guessing it shouldn't) so it either needs the foresight sliding back to hold it tighter or a washer/shim behind the sight. The sleeve slides over the barrel and is held in place by the foresight and there is a threaded piece at the end of the barrel that screws onto the barrel.

Undo the front stock screws and the rear one at the front of the trigger guard. The action should lift out of the stock, and leave behind a small cranked bit of metal that holds the trigger adjusting screw. It is located by the front trigger guard screw so if you have fully removed the screw there is a chance it could fall out of the stock. Lift the cocking arm out of the cylinder and undo the barrel pivot screw and remove the barrel/breech block. If you want you can undo the tiny screw on the LHS of the breech block and remover the barrel plunger and spring for lubing. I usually push the plunger with a small block of wood when removing or replacing it. Once you have lubed it, replace the spring and plunger back in the block and tighten the screw.
I am not sure how the safety attaches to the gubbins, but assume it would just hook on. The safety is just a simply rocking bar that stops the trigger from moving. It is located on a bar in the cylinder sleeve and centralised by a spacer and a spring. It does not need removing for the strip.
Put some weight onto the sleeve and you can remove the trigger pin/cylinder pin. Once it is removed, slowly release pressure and remover the cylinder sleeve, guide, mainspring and piston.
The piston washer is leather, with a fibre spacer below it and is held in place by a screw, ( which I prefer), rather than a threaded nut, like some of the Milbros.
As the screw was tight and the washer in good condition, I did not remove it. The mainspring in mine was something that someone had fitted and left the end rough, so I flatted the last coil and cleaned it up.
Go to pt 2

[ggggr]

Replace the piston, mainspring and guide into the cylinder and then the cylinder sleeve. Compress the spring and locate the sleeve with the cylinder pin/trigger pin or a slave pin/punch.
The aluminium trigger is pretty much the same idea as the early triggers, with the 3 floating bit of sear. It is a bar steward to get the trigger pin through the all the bits. On older German Dianas, they had 2 pins, 1 to hold the sleeve and one for the trigger, which made it easier to fit. This is one reason I do not like working on the Milbro versions. If you are lucky, you may get the pin through first time or you may be unlucky and spend 30 minutes swearing at it. I made up a small aluminium slave pin to put through the trigger and sears first to give me a fighting chance of getting the pin through and it went in with a bit off jiggling.
Replace the barrel and locate the cocking arm in the cocking slot of the cylinder and replace the cylinder end cap and drop the action into the stock (remembering to replace the trigger adjust bit if you removed it from the stock earlier). Replace the stock screws.

This is like most Milbros in that it should be better. The addition of a 2nd pin for the cylinder sleeve/ trigger would help. I prefer the simple idea of the safety mechanism on this to the G25/27 etc set up, but guess the actual catch was very flimsy. The front stock screw holes do not seem to be deep enough for my liking, and maybe the original screws came loose and resulted in the stock breaking. I only fired 5 shots with it as it was getting dark, but it does seem accurate at short range. It was dieseling a little but this is normal when you have cleaned a gun out and used modern lubes as the old stuff take a while to burn off.

[Phil Russell]

Having just completed another strip, service and rebuild of a Original 45 from 1980, I found a much simpler way of dealing with that beastly trigger safety spring. I thus offer a revised strip guide: I have left my original (very apt!) notes in post 58 in case people want to try a fiddly way...

REVISED MARCH 12 2016: BREECH SEAL: BS110 2.62cs

ADVICE: Make a slave pin 27mm long x 5mm diam to help remove end block.

A spring compressor is essential.

STOCK REMOVAL
2 screws front. Rear pin goes though the trigger. It is a bush and pin. Remove pin from left.

SPRING AND PISTON REMOVAL
Mount action in a compressor, barrel left and trigger unit upwards. To gain access to the spring and piston, the trigger does not need to be removed. Take up tension on the end block using a spacer on the underside, flat part of the safety.

Release and remove small spring on extreme left... simple.


Dismantle using the slave pin (recommended)
Use a suitable punch to push out the right hand pin securing the end block, but leave punch in place.
Use the slave pin to drive out the left cross pin holding the end block. The slave pin passes into the trigger block but sits clear of the sides of the cylinder. It serves to lock the safety spring in place in the trigger unit. Without the slave pin the safety spring springs down once the normal pin is removed. It is difficult to replace the pin without a fiddle!

Dismantle with no slave pin (not recommended)
Use a punch to drive out the lh pin, leave the punch in place. Drive out the rh pin, leave punch in place. Pull the punch from the lh hole. You will hear a click as the safety crinkle spring springs down … you can see the crinkle if you look through the pin hole.

To continue with either method:
Remove the punch from the right pin hole and allow the mainspring to push the end block out. The spring guide sits on a peg on the end block and may come out with the end block.

The spring preload is not excessive but take care. With the spring not under compression, remove spring.

To remove the piston, the cocking arm must be released. I released it at the breech block end by pushing the pin out. The pin may be held in place with a circlip, or maybe not. Remove cocking arm.
To remove the piston, the cocking shoe must be removed. The shoe is held in place by the piston sleeve so the sleeve must be pushed forward until the shoe falls off the end into the piston body. The piston can now be slid out. Retrieve the cocking shoe. There is a washer inside the sleeve, do not lose it.

The piston washer is leather.
Service as you wish.

Notes on a spring: The Original spring measured 34 coils at 3.12mm cs, 20.75 od and 14.44 id. I replaced with a Titan No.1 using 27 coils at 24.7mm long for .177. This meant cutting off c. 3 coils from the supplied spring. I tried fitting the full length spring but stopped when installation force became clearly excessive. Removal of 2 coils was still ott, a coil compressed was hovering on 12 so the compressed coil was removed to give 11.7 / 11.6. The spring length now just allowed the end block to locate in the action before taking up compression.

REASSEMBLY

This is basically a reverse of the above but these notes may help.
All the following was done with the action in the compressor.

Refitting the cocking shoe: A bit fiddly. I used a piece of 0.25mm ptfe sheet just inside the piston to hold the cocking shoe in the slot in the piston body. Now insert the piston into the action; it will be necessary to push the cocking shoe down a little to allow it to fit into the action and then show in the action cocking slot. Then use a piece of bent wire to hold the shoe in position while the ptfe sheet is removed and replaced by the piston sleeve … the sleeve will pass under the shoe and hold it in position. If not already done, replace the steel washer inside the sleeve, over the latch rod. With the spring, push the piston / sleeve to the bottom of the action.

Refit the cocking arm.

Add the spring guide, flat uppermost, and end block, making sure the end block is positioned correctly with the lugs over the flat of the guide.

Refit end block with slave pin.
Push the end block in using the compressor, making sure no block component on the left can foul the block as it enters the cylinder. Make sure the slave pin does not catch on the cylinder.
Continue compression until the slave pin appears in the lh hole in the cylinder. As a safety measure, add a punch through the rh hole but do not release spring compression. Using an original pin, carefully drive the slave pin out as the original pin is tapped home. Now add the rh pin. It is now possible to release spring compression. Replace the small spring on the lh side of the block. Check that the safety slides in and out with a distinct locating feeling as the safety spring moves on the lh cross pin.

Refit end block, no slave pin.
Compress end block until both pin holes are aligned. Use a punch to ensure free access is there for the rh pin .. inspection with a torch is useful. Add the rh pin.

Look into the hole for the lh pin. Note you can see a crinkle leaf spring across the hole. This part of the leaf spring needs to be pushed upwards i.e. towards the trigger blade to allow the lh pin to pass under it.
Using a small punch, insert the punch under the crinkle and push the crinkle upwards while introducing another punch from the other side of the action to hold the spring up. Repeat operation; eventually it will be possible to fit the lh pin in place.

If all fails it is most likely that the safety spring has slipped in its locating slot in the safety slide. There is no real alternative now: remove end block, pull safety out, relocate spring and try again.

Refit the spring on the left.

Refit action to stock: Simple but take care that the pin through the trigger has a clear path. This can be achieved by slightly moving the trigger and using a drift to align everything. Refit the stock pin and screws.
Cheers, Phil

[Phil Russell]

FWB 124/127
Useful information: Mainspring is 40 coils of 2.94mm wire, 14.8mm inner diameter, 20.8mm outer diameter. The removed length was 320mm; a new spring may measure c. 333mm. Breech seal is 3mm c/s, 16mm od, 10mm id.
A little time ago someone asked on the BBS for advice on stripping one of these sought after classics. I thought there was a guide on the Idiot’s Guide, but there was none. So here it is, a guide based on my very recent experience with a virtually new 124 (.177; the .22 is the 127). It was clear the rifle had had very little use. On first test shot, the pellet did not leave the barrel. Oh dear … classic symptom of a failed piston washer. Time to look:
Note this Guide does not include a trigger strip.
Important: You will need a spring compressor with a ‘long throw’ … there is considerable preload on the original spring. Other tools in addition to normal turnscrews would include a short (6”) plastic cable tie. I use one that you can release and use again. Small wooden block to fit on the end block so that the safety catch is not compressed when dismantling the rifle.
Remove foresight, two small screws. Put somewhere safe. Remove stock; two screws at front (do not lose the serrated washers) and the front screw in the trigger guard. Lift action out of stock and put stock safely to one side.
Place action in the compressor, preferably trigger uppermost and barrel to the left. Make sure it is secure. My compressor lets me clamp the cylinder to the compressor bed to avoid undue movement. Place wooden block in position so that when you start to remove the end block, there is no pressure on the safety slide. Just take up the pressure on the end block. Now start to undo the end block securing bolt in front of the trigger. I used a 7/16” af spanner (I think this is 11mm) as it was to hand and fitted perfectly. It may help to just nip the end block up as you release tension on the bolt. Remove bolt and then slowly unwind the compressor about ½”. Now take the cable tie and wrap it around the end block, passing under the safety slide, and secure it. This holds the safety slide in place. This is not absolutely necessary but does help and it prevents the safety slide and sear spring from pinging away as the end block (trigger block) is released. Continue unwinding the compressor until the trigger block and then the spring become free. The end block and spring simply lift away. A spring guide is part of the trigger block.
To access the piston it is necessary to release the cocking arm. Undo and remove the small screw on the breech pivot bolt followed by the pivot bolt itself. The barrel assembly and cocking arm can now be released from the breech jaws and the cocking arm released from the ‘shoe’ in the cocking slot. Note there will be a domed shim washer fitted in a recess in the breech jaws, right hand side; do not lose it.
To remove the piston, slide it towards the end of the cylinder where the cocking slot is much wider. It is now possible to remove the cocking shoe, after which the piston just slides out. My piston head was indeed disintegrated; bits were left in the cylinder and I had to dig the remnants out of the end of the piston. A new head is a push fit into the end of the piston.
After cleaning all parts, reassembly is a reverse of the above: Lubricate the piston and place in the cylinder, slide piston in so that you can fit the shoe in the slot … the cocking arm contact point towards the trigger block end.
It is tempting to continue assembly of the spring and trigger block to the cylinder before fitting the barrel assembly. Do not do so.. the pivot bolt cannot be fitted this way. So: fit cocking arm end into the shoe and slot the well greased breech jaws plus shim washer into the cylinder jaws and screw in the pivot bolt. I found it easier to do this before putting the action back into the compressor. With the barrel assembly fitted add the lubricated spring and place assembly in the compressor. Add the trigger block to the spring, trigger uppermost and add the wooden block again, making sure it does not press on the safety slide. Begin to wind the trigger block in, making sure that the safety slide enters the cylinder in the process. Continue to compress the spring until the trigger block has just over ½” to go and then remove the cable tie. The trigger should be central to the slot in the cylinder. Continue compression until the securing bolt holes line up and add the bolt. It may be necessary to jiggle the holes to enable the bolt threads to nip. Do not force the bolt; when correctly aligned the bolt will go in virtually under finger pressure. Tighten bolt. Release pressure on the compressor, remove action, refit stock and sights. Job done.
After this service the rifle was consistent at 11.4 ft lbs with AA Field.

Cheers, Phil