There are two screws on the top and bottom. It may be a bit snug but the buttstock will pull out.

It is merely on there by friction.

Keep in mind that there are tabs on the breech end of the forearm. They are fragile. 

After removing that part the previous barrel band will come off.

It holds in the next part. It is most likely stuck and will need some persuasion but it is just stuck. 

It appears that the screw is holding the front sight in but it is not.

Do not worry about that spring. We will remove it later. 

Now that pesky barrel band will officially come off.

It is now on there by friction. A little wiggling and it will slide off. 

It holds the two halves together.

Only these screws truly come out. The other ones are for aesthetic purposes. 

It should come off easily.

Orientation will come into play when it goes back together.

This is what it looks like apart. 

Use something that has a slight hook on it to pull it out. 

Pull tension and move it around and into the inside.

Let is ride inside. It will stop shortly. 

Not the one the tip is point at but there is one just inside. Use a tool with a hook on it. 

This is the spring to loosen.

It should NOT have tension.

It will slide out. Possibly fall out. 

This is what the other side of the trigger looks like. Just a reference to know what orientation that spring is in.

There should NOT be tension on this one either. 

It should nearly fall out by now. 

Once again, NO tension.

It is slightly wedged. 

It should just about fall out.

It WILL fall out. This view just lets you know the orientation.

Tension must be applied to the plunger assembly to remove this retainer. 

Use a small flathead screwdriver to pull it out the breech end of the gun. 

It might be stuck in it by friction or grime. 

The two halves have a tendency to stay together. Some wiggling and patience will get them out. 

This is how they go together when assembled.

Use something with some strength, length, and curvature to get inside and push the abutment seal toward the breech end of the gun. 

The abutment seal is about this far into it. Thus, you don't need to go far into it. If you dig too deep into it, you may damage it. 

This is the orientation for the abutment seal.

Push the rod (with abutment seal on it) all the way in until it stops. 

When the metal rod attached to the wooden dowel rod comes out and the wooden dowel portion bottoms out.

Compress the plunger assembly to remove the piston seal and wiper (foam or felt) washer. 

This is what it looks like when the head is off the plunger assembly.