The Beeman P1 air pistol: Part 4
by Tom Gaylord
Writing as B.B. Pelletier
This report covers:
- Step 1
- Step 2
- Step 3
- Step 4a
- Step 4b
- Step 5a
- Step 6
- A special tool
- Step 7
- Step 8
- Release the clamp slowly
- Step 9
- The piston seal
Today is the day I disassemble my new/old Beeman P1 pistol. Several readers have been waiting patiently for this report.
The tools you need are:
12-inch/30-cm trigger clamp
A set of pin punches
2mm Allen wrench
2.5mm Allen wrench
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.
Remove both grip panels.
Loosen the 2mm Allen screw at the bottom front of the gun
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.
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.
Drive the large pin out of the rear of the frame, left to right.
Pull the hammer back. This unlocks the powerplant.
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.
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.
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.
Remember that 5-inch piece of clear vinyl tubing? Slide it over the powerplant before installing the powerplant in the clamp.
Put the powerplant in the trigger clamp.
Remove the end cap.
Now we will take the tension off the mainspring and you will see what the clear tube does.
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.
Each time the hammer taps the trigger more spring comes out.
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.
The piston seal
The piston seal is like new. I have no intention of replacing it.
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.
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.