Idiots guide to classic airgun strips (pt 1)

[ggggr]

Now you have all your clean and lubed bits you can put them back together. Put the leather buffer washer into the cylinder and push it down to the end. I inserted the other leather washer into the piston and pushed that down. I pushed the barrel through it a few times to make it easier for when the barrel goes back in. Slide the piston into the cylinder and push it right down. Get the cocking arm and slide the bit that goes into the grip frame in far enough so you can locate the small cocking link into the slot in the cylinder. Once it is in, locate the cocking arm and pin in the grip frame. There is enough space to wangle the trigger and trigger spring into place. The trigger spring locates in a small hole in the frame. Locate the trigger pivot pin. Slide your mainspring onto the barrel and endcap, with the foresight just left of centre as you look from the front of the gun. You should now be able to compress the spring and locate the barrel through the washer in the piston. IF YOU CANNOT,try it without the mainspring to open up the leather washer in the piston again first.
With the barrel located and spring compressed, the endcap should locate with a slight clockwise twist. Get the right grip with the screw through it and place it at it's hole on the frame. Locate the locking bar and spacer and then push the screw through. Fit left grip and nut and that is all done apart from the breech washer. If you think it is worn, just make up a small disc and replace it. It sits in a hole on the plate at the back. My gun was not seating and sealing properly even after fitting a new washer. It was blowing air out of the top of the plate. I did not want to try to heat and bend the plate so tried a thin leather washer, then a plastic washer with a hole in the centre for the breech seal to go through. The gun would not lock up like this. I Eventually made a paper gasket to go on the plate and that has cured the leak for now. I dont know if very thin shim steel or similar would work.
The gun now cocks,holds and fires. It is low on power and the accuracy is not great. I think maybe accuracy could be improved slightly by fitting washers (steel or plastic) that fitted the barrel OD and the cylinder and piston ID, with the cylinder buffer washer and the leather washer in the piston. Pellets were tight in my barrel and maybe a clean with a brass brush might help. Light wadcutters will probably shoot better although sizing pellets first helps as well.
It is a very small pistol. If you are a collector and you dont have one, then buy one. If you like plinking, there are better older guns to try. There are no spares for these guns so if the piston wears you would have to get one built up or turned up. A fairly solid little gun but other than buying this one so I could do the stripdown, I would not be looking for another.

[ggggr]

These are the stripdowns for the Diana and Milbro rifles with the above numbers and the safety catch fitted. These are more or less G25 and G27 guns but maybe with different sights. Some have a plastic rearsight and some a metal one. Some have a barrel pivot bolt and lockscrew and some just the bolt. Some have a cocking arm pivot screw and some a rivet, so use common sense and read through this to save me doing 4 guides.

Remove the sights if you want to. Undo front 2 stock screws and rear one in front of the trigger guard. You can remove the rear trigger guard one if you want to take the guard off. Lift the action out of the stock. Undo the barrel pivot lock screw if it has one and then the barrel pivot bolt. Lift barrel and cocking arm away from the cylinder. If you want to remove the barrel plunger and spring, do it now. Press the plunger with a bit of wood and undo the small screw on the LHS of the breech block. Release the wood slowly and the plunger and spring should come out. Clean and lube and replace.
Undo the screw holding the plastic safety on and remove the plastic catch. Knock the metal endcap off the end of the cylinder (often tight and may need tapping). I'd then undo the trigger adjusting screw and remove the sear spring and the trigger spring. The adjuster screw has a circilp on it but does not need to be removed for this strip. Tap the trigger pin/cylinder pin out (checking that the safety pin is holding the sleeve in the cylinder) and remove the trigger. The trigger may need some wangling as the rivet may catch on the sleeve. Now get a piece of wood and press on the sleeve, while pushing the safety pin into the sleeve. Slowly release pressure and the sleeve should come out. Take note of how the safety goes into the sleeve. The guide, mainspring and piston should now come out of the cylinder. There are a couple of types of piston washer/buffer/nut set ups. Clean and lube and be ready to put the gun back together.

[ggggr]

Replace the piston, mainspring and guide into the cylinder. The sleeve should go in next but first a quick word on that. Looking from the back of the gun, the spindle should go into the sleeve from you left,the spring should go on it next, then the safety cam,then the safety plate. There is a pip on the RHS of the cam and the LHS of the plate to locate and show you that you have them in the right place. The little cut out crescent on the cam lets the trigger be pulled and the rounded piece stops it. I'm sorry that I cannot make it clearer.
Push the sleeve and safety into the cylinder and push down enough to use slave peg to hold the sleeve. The safety spindle should locate in it's hole on the RHS of the cylinder, but you may have to locate it by screwing the catch screw in and gently guiding it into place. Place the trigger into the housing and attempt to line up the trigger and 3 sears and then push the pin through. A drink may help! A slave pin might help, but even then I reckon it is a knack. Once the trigger is located and the pin through, put the plastic safety catch on and screw its screw home. Hook on the sear and the trigger springs and adjust the trigger adjuster up enough to put pressure onto the spring. You can set it properly later. Replace the endcap. Place action into stock and replace the 3 stock screws. Replace the sights.
I like the old Diana 25's and the German versions with one pin to hold the sleeve and one for the trigger are better to work with. I feel that the later Milbro "improvements" did not solve anything and actually made the guns worse. 2 pins for the sleeve and trigger would have helped and then a decent rearsight with proper elevation and windage instead of the old "ramp" sight in a dovetail or the crappy plastic thing in a dovetail.

[ggggr]

UPDATE 23 06 2017--ANOTHER PISTOL ARRIVED WITH A DIFFERNET SEAR/PLUNGER AND NEEDS STRIPPING DIFFERNTLY TO THIS GUIDE. YOU NEED TO REMOVE ALL THE TRIGGER AND SEAR BEFORE YOU CAN REMOVE THE CYLINDER END PLUG.

This arrived today. I have been after looking at one for a while. It is an underlever pistol with a flip out loading tap. It is of heavy construction with basic sights.
Tap out the rear sight if you are worried about damaging it while you are working. There is only one screw holding the action to the frame. It is a large screw through the bottom of the grip. The smaller hole to the rear of the frame is a hole for adjusting the trigger, although this example was missing the screw (3 or 4 mm). After you undo the large screw and lift the action out of the frame, watch out for a trigger spring flying out. This is a coil sppring that sits in the frame like the Diana/Milbro G4, Slavia Zvp etc.
Looking from the front of the gun towards the cylinder, you will see a small screw on either side of the cylinder. Still looking from the front,the one on the left is the tap pivot screw and the one on the right contains a coil spring and a bb that loacte the tap when it is closed. Remove,clean and lube these bits and keep them somewhere safe.
Looking at the action from the rear, into the trigger housing,you will see the forks of the sear on either side of a tube. This tube is part of the trigger. You can tap the cylinder and this tube should drop out. You will see that it has a notch on it (like a sear) to hold the piston rod when the gun is cocked.
With that out, you can knock out the cylinder endcap retaining pin. There is not much pressure so it should not fly, but it always pays to keep a bit of pressure on endcaps when removing pins. With the cap removed, the mainsprings (yes 2, like the rifles) and the guide should come out. The guide was at the front of the springs and I put it back the same way. I don't know if it would work at the rear. It is very small because of the inner mainspring.
Now tap out the trigger pin at the front of the trigger housing and remove the trigger and its small hairpin spring. Try to see how it goes for when you put the thing back together. Knock out the rear pin in the housing and remove the sear from the back of the housing.( Not knowing what sort of screw the trigger adjuster should be,you may have to remove this screw first)
Undo the cocking arm pivot screw and you should now be able to use it to push the piston to the back of the cylinder. When it gets most of the way there, the cocking arm should drop out of the cylinder and you can then remove it from the front of the housing. Withdraw the piston from the cylinder. The piston washer is held by a threaded nut that has 2 holes for a peg spanner. As the nut was not tight, I used the nose of some long nosed pliers to undo it. There was a steel washer under the piston washer.
Clean and lube every thing up. Go to part 2

[ggggr]

Put your steel washer,piston washer and nut back on the piston and nip up the nut. You could use some thread lock or gently peen the nut to stop it coming undone.
I would now replace the loading plate and the locating bb, with the bits you have been keeping safe. The plate has a pip on it for the ball to locate on so you should be able to work out which way is goes. Slide the piston part way into the cylinder and then slide the cocking arm into the front of the trigger housing and slide it towards the rear of the cylinder (helps if the action is upside down) until it locates into the cylinder and piston slot and then slide it forwards, which will pull the piston fully forwards into the cylinder. Locate the cocking arm pivot screw.
Now slide the sear into the trigger housing from the rear, with the rounded side to the front and the fork to the rear. You should be able to work out which way up it goes by looking at he trigger before you put it in. Replace the pin.
Now get your trigger and trigger spring (sits in the middle of the top of the trigger). The straight leg sits n top of the trigger and the hooked bit sits against the cocking arm. Locate it and replace the pin.
Now place the guide and mainsprings into the piston and locate the end cap. With the cap in place, you should be able to push the tubular trigger piece through the hole under the rear of the trigger housing into the cap. With this located, you can replace the endcap pin.
If you have a screw for the trigger adjuster, you can fit that now.
Put the little coil spring into the tubular trigger piece and then locate and gently lower it into the frame.
Locate and replace frame screw.
Replace sight if you took it off.
I need to look at this and get a few more shots out of it. The trouble with something like this is you cannot get parts if something goes wrong.
The 2 mainsprings are quite lightweight and might be better with one spring, but I'm leaving it as standard for now. The trigger is heavy and cleaning up the face of the tubular bit that holds the piston did not help much. None of the faces looked bad. I am always wary of adjusting the triggers to reduce engagement as it can cause problems.
It plinked! It was shooting high, despite an attempt to heat up and bend the rearsight down a bit. The trigger is heavy, even with the adjustment. IT was not very accurate, but some of that might be due to the strip down and settling. The smoking was stopping and the grouping was getting better.
It is a strange pistol. The loading plate seals very well but the gun feels quite harsh to shoot. Maybe it is a bit top heavy. Like I said, maybe one spring and a guide at the rear might help. The trigger is quite simple but overly complicated for what it is. I feel that the Slavia ZVP/Diana Modell 5 set up might have been a cheaper/better option.
OK---It has a heavier trigger and is not as accurate as the Gamo Falcon that copied aspects of it, But I bet it will last a lot longer

A little update. I tried leaving the inner mainspring out and it reduced power too much.
I noticed that the foresight was moving so took out the blade and tapped the top of the dovetails.
I will adjust the sight some more shortly.
What I have noticed, is that even shooting two handed, you have to really GRIP the pistol otherwise it tends to go all over the place. I think it is a combination of a heavy trigger and a top/front heavy gun. With a good solid grip, it was starting to group ok.
With the trigger being poor, I would forget about normal trigger technique. It is a bit like an RO 72 in that respect, with the best results achieved by "Yanking" on the trigger firmly, rather than trying to get up the slack and judge when it will go off! If you do try a normal technique on it, you will probably find you will pull get the veins in your arm popping and you will pull the shot anyway.
I've tried shooting with the wire stock on. It does not give a great sight picture and you do feel very cramped. It is actually pretty accurate like this.

[ggggr]

This is for a pre war, full stocked Diana 25. This is the one with the screw on end cap. I've been told earlier ones had the cap inside the cylinder.
The strip is similar to the post war model and the British made ones, with only a few differences.
Undo the front stock screws and the rear one that is in front of the trigger guard and lift the action out of the stock.
Undo the cocking arm pivot lock screw and then the pivot and remove the cocking arm.
Undo the barrel pivot lock screw and then the barrel pivot screw and remove the barrel. It looks like there should be shims on the breech block but they were missing on mine. If you want to remove the barrel plunger, depress the plunger and then undo the grub screw on the LHS of the breech block. Release the pressure on the plunger and it and its spring should come out. You can clean,lube and replace it now.
Undo the cylinder end cap.
Remove the trigger spring from the tang one the cylinder sleeve. Undo the lock nut on the cylinder/trigger pivot screw. Put some pressure onto the cylinder sleeve and the pivot screw should push out. Remove the trigger. Release the pressure and the sleeve should come out and then you can remove the guide,mainspring and piston.
The piston has a leather cup washer and a fibre spacer. They are held on with a screw. If you need to remove or change these, you will have to drill out a small pin on the side of the piston, that is a keeper for the screw. Luckily mine was in good condition.
Clean and lube everything and go to Pt 2

[ggggr]

Put the piston,mainspring and guide into the cylinder and then the cylinder sleeve. Make sure it is the right way round. Compress the spring and use a slave peg to locate and hold the sleeve. Keeping pressure on, you should be able to locate the cylinder screw/trigger pivot screw and push it through the trigger. Once located, replace the lock nut. Replace the trigger spring, making sure one end is on the TANG of the cylinder sleeve and the other is on its PIP on the trigger. Screw on cylinder end cap.
Locate breech block shims and place barrel in the jaws. Locate and screw home the pivot screw and the lock screw.
Locate cocking arm and replace its pivot and keeper screw.
Refit action in stock and replace the stock screws.

I think this is a nice little rifle. I was surprised at how good the internals were on mine. The piston washer was in good condition and the piston head screw retaining peg had no witness marks round it. I had a quick plink and it is accurate enough. The trigger has a long pull but is pleasant to use.

It is interesting to note that the German post war 25's had one pin to hold the sleeve and one to act as a trigger pivot. The British version just had one pin to do both jobs.