by Tom Gaylord
Writing as B.B. Pelletier

Part 1
Part 2
Part 3

Beeman P1
Beeman P1 air pistol.

This report covers:

  • Tools
  • Step 1
  • Step 2
  • Step 3
  • Step 4a
  • Step 4b
  • Step 5a
  • 5b
  • 5c
  • 5d
  • Step 6
  • A special tool
  • Step 7
  • Step 8
  • Release the clamp slowly
  • Step 9
  • The piston seal
  • Summary

Today is the day I disassemble my new/old Beeman P1 pistol. Several readers have been waiting patiently for this report.

Tools

The tools you need are:
12-inch/30-cm trigger clamp
A set of pin punches
2mm Allen wrench
2.5mm Allen wrench
Plastic/rubber hammer
Medium slotted screwdriver
A 5-inch length of clear vinyl tubing with a 1.25-inch (31.75mm) inside diameter

It will also help to have a couple small flat-bladed screwdrivers to help pry the piston out at the end of disassembly. Let’s go!

A lot of this will be pictures. The captions will explain what I’m doing.

Step 1

Remove both grip panels.

Step 2

Loosen the 2mm Allen screw at the bottom front of the gun

Beeman P1 2mm screw
Loosen but do not remove the 2mm screw at the bottom front of the pistol.

Step 3

Stick a paper clip through the interrupter hole in the grip to hold it fast.
Beeman P1 paper clip
A paper clip through the hole in the interrupter holds it fast.

Step 4a

Drive the front pivot pin out of the gun.
Beeman P1 pivot pin out
Drive the pivot pin out.

Step 4b

Remove the top of the pistol. Lay the pistol on its sights (upside-down) and ease the top that contains the barrel off the bottom. This will take some doing if the pistol is old and hasn’t been apart, but if you thumb back the hammer that locks the upper at the rear and apply upward (downward?) pressure, the top of the gun will come out of the bottom. The twin cocking link arms have to be slid to the rear of the powerplant to remove them, but you will see what to do.

Beeman P1 top off
The top of the gun, containing the barrel, lifts off the bottom. Invert the pistol to do this. The twin cocking links slide to the rear of the pistol to release.

Beeman P1 barrel
There is the barrel. Now you know where it lives and how it is held in.

Step 5a

Loosen but don’t remove the 2.5mm screw on the bottom of the frame. There’s only one. I didn’t take a picture of this one.

5b

Drive the large pin out of the rear of the frame, left to right.

Beeman P1 large pin
Drive the large pin out, left to right. Notice I’m not removing the small pin that’s behind and above it.

5c

Pull the hammer back. This unlocks the powerplant.

5d

Loosen the 2.5mm screw some more more and tap it in with the soft hammer head. This screw holds the powerplant inside the lower frame of the gun. Unscrew it as far as it will go and tap the screw head to loosen the powerplant assembly more. Then remove the screw.

Step 6

Remove the powerplant assembly from the lower frame. My gun has probably been together for 40 years and it was difficult to remove this assembly, but persistence paid off.

Beeman P1 powerplant assembly
The powerplant assembly contains the piston and mainspring. This is what makes the P1 go! It is still assembled at this point.

A special tool

Now you have to make a special tool. The 12-inch trigger clamp needs a notch on the lower part of its face on one end. The pictures will show how and why.

Beeman P1 cut notch
A knife is used to notch the bottom face of one end of the trigger clamp. This notch will fit a small projection on the powerplant.

Beeman P1 notch fits powerplant
The notch fits that small silver projection on one end of the powerplant. That will hold the powerplant in place when it is clamped!

Remember that 5-inch piece of clear vinyl tubing? Slide it over the powerplant before installing the powerplant in the clamp.

Step 7

Put the powerplant in the trigger clamp.

Beeman P1 powerplant in clamp
The powerplant is in the clamp with the clear tubing around it. That small silver projection is inside the notch we made at the left of this picture.

Step 8

Remove the end cap.
Now we will take the tension off the mainspring and you will see what the clear tube does.

Beeman P1 remove end cap
Drive out the pin to release the end cap. The clamp will hold the powerplant, so make sure it is secure in the jaws before that pin comes out!

Release the clamp slowly

Now we will take the tension off the mainspring. Tap the trigger of the clamp lightly with the hammer and the clamp jaws with open slowly. Keep the clear vinyl tube around the spring as it comes out of the powerplant. The spring guide is not in the end cap. It’s inside the piston. So the spring can get out of control as it relaxes outside the powerplant tube.

Beeman P1 spring comes out
I slid the clear tube back so you could see the mainspring. Beyond this far out, the clear tube needs to be in place.

Each time the hammer taps the trigger more spring comes out.

Beeman P1 spring relaxed
The mainspring was under a lot of compression!

Step 9

Remove the piston. My piston was tight inside the compression chamber and it took a lot of prying with screwdrivers through the many holes in the compression/spring tube that are there for that purpose — I think! But it came out.

Beeman P1 piston
The P1 piston.

The piston seal

The piston seal is like new. I have no intention of replacing it.

Beeman P1 piston seal
Piston seal is perfect!

The mainspring, on the other hand, has a slight kink. It’s usable, but since I have a new one that I got with the pistol, I’m replacing it. The old mainspring was caked with a dry crumbly substance that looks like dried-out grease. It was even shiny! From the outside of the powerplant it looked like moly, but it’s not.

Beeman P1 mainspring
The mainspring is not bad, but I have a new one, so I’m replacing it.

Summary

This entire disassembly took 45 minutes, which included taking all the pictures. Had I just worked on the gun it would have taken half that time. This process goes quickly and easily. I haven’t done it for 21 years and it still went fast.

Next I will lubricate the pistol and assemble it. Then I’ll test it for power again.

I still need to find why the pistol hesitated between low and high power, so there is more to be done. I’m enjoying this.