Weihrauch HW40PCA Air Pistol

 

By Todd Cooper

 

 

The German made Weihrauch HW40PCA air pistol is a single stroke pneumatic design complimented with an accurate barrel and sweet trigger. The contours of the pistol are so pleasing that I ordered a .177 version, through a Beeman dealer (P-3 pistol), as soon as they became available in the USA. After more than 5 years I still enjoy shooting this mild powered plinking pistol.

 

The HW40 is constructed of modern polymer and metal materials. The outer body/frame of the gun is constructed of fibre-reinforced polymer. Polymer is a very strong synthetic material, which is used in the manufacture of the Glock handgun. Even the wheels and cams of some compound bows are made of polymer. The inner parts of the air pistol are all made of metals. Metal parts would include: barrel, safety, trigger, barrel latch, compression chamber, transfer port, piston and rod, pivot points and pins. Metal construction is everywhere it is needed.

 

The HW40 design looks similar to a modern 9mm handgun, with a finger groove grip and combat trigger guard. Some shooters say it resembles the Desert Eagle semi-auto pistol. Either way, I think it looks pretty cool and the compact design is quite welcome.

 

The cocking cycle of the pistol is started by releasing the upper section of the gun with the barrel latch (mock hammer). The upper section is then swung over to complete an arc of approximately 180 degrees. Finally, the upper frame is returned to the lower frame while simultaneously compressing air into the chamber. This mechanism is referred to as an over-lever pneumatic and is shared with other pistols such as the Webley Nemesis and Gamo Compact.

 

The trigger on the Weihrauch is adjustable with a single set screw, located on the trigger itself. I have had my HW40 since March 1999 and still have not touched this adjustment screw. My recent trigger pull test showed a 16.5 oz pull weight when using the "lift method" of testing.

The HW40 grip is integrated into the polymer frame. This makes grip panel changes impossible. Some shooters have become innovative and used the slip-on grips offered by Hogue (Hand-all) and Pachmayr. I found the unaltered factory grip to be a bit slippery so a couple of short strips of self adhesive, gritty, institutional stair tape were applied down the back strap and to the right side of the grip. After 5 years the tape is still working fine.

 

 

 

TOPICS OF INTEREST

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HISTORY

 

The Weihrauch HW40PCA first appeared in the USA as the P-3 in the 1999 Beeman catalogue edition #22. Beeman dropped the Webley Nemesis from the catalogue this same year. The two pistols are very similar in design so Beeman must have decided the P-3 would be the more popular choice.

 

The HW40 was not Weihrauch’s first entrance into the single stroke pneumatic market. The more expensive HW75 (Beeman P-2) has been around since the 1980s and operates from a similar compression system.

 

The Webley Nemesis and Gamo Compact pistols also pre-date the HW40 introduction. It’s quite possible Weihrauch choose to produce the 40 to compete in the mid priced SSP market, instead of only the higher priced market of the HW75.

 

 

 

 

SPECIFICATIONS

 

 

** Beeman rated accuracy is “best 3 shot center-to-center group recorded at 10 metres”

 

 

 

VELOCITY RATINGS

 

 

 

Beeman’s velocity numbers are always taken with the lightest possible pellet but the accompanied energy ratings indicates this fact. The Weihrauch velocity number for the .177 caliber is a little slower but a slightly heavier pellet will have this effect. The pistols are the same so they are capable of the same output.

 

 

 

VELOCITY TESTS

 

The following velocity numbers were recorded when my HW40 was approximately 4.5 years old. Previous tests, during the first year, gave similar results.

 

 

Below are some .20 caliber HW40 velocities courtesy of JohnKT (Airgun Forum member). The pellets were weighed by John for this test.

 

 

 

 

ACCURACY TESTS

 

The HW40 accuracy was tested in two different ways. One method was by using a sandbag rest and a Bushnell Sportsman 3-9X air rifle scope (set at 9X). The second method was by shooting offhand using a non-magnifying 30mm Interaims red dot sight.

 

The HW40 is a very easy pistol to shoot accurately. There is no recoil to be concerned with and the muzzle jump is very mild. When the trigger is pulled, the valve opens and dumps the compressed air charge down the barrel. This causes a very slight upward muzzle movement but it has never seemed to significantly affect accuracy during my testing.

 

Offhand Groups

The red dot sight simplified the aiming when offhand shooting. The bright 4 moa dot is placed in the center of the black bullseye and the trigger is gently pressed. There are no sights to align or gaps to keep equal but I do try to keep the dot close to the center of the lens for each shot.

 

When I am having a typical offhand shooting session with the HW40 I usually group .75” to 1.0” ctc for 5 shots at 10 metres using the isosceles hold. On a couple of occasions I shot 20 pellet groups from 10m and managed 1.0”ctc.

 

Here are some examples of 5 shot offhand group sets using the Crosman Premier Light pellet. The groups within each set were shot consecutively.

 

Offhand Groups @10 metres

 

  

 

 

 

 

 

Benchrested Groups

The pistol was wedged into a leather rabbit ear sandbag for all 10 metre and 20 yard rested shooting.  The adjustable objective was used to eliminate parallax in the 3-9X air rifle scope.

 

 

I did further testing with the Crosman Premier Light pellet to make sure the above results were typical. Following are two more sets of 5 shot groups:

 

 

Post Script - The 4.52mm JSB Exact pellet was tested. This pellet fits the HW40 much better than the older 4.50mm version. The larger 4.52 seems very close in accuracy to the CPL.

 

 

 

 

 

 

Velocity-Accuracy Summary

We all know Beeman uses the lightest pellet for their velocity testing. Their stated velocity for the .177 caliber P-3(HW40) is 410 fps and their stated energy rating is 2.4 fpe. The 6.5 grain Beeman Laser pellet will generate 2.4 fpe at 410 fps so this would be the pellet they used. My HW40 seems to be shooting fine, producing over 2.4 fpe with every pellet tested. With the 6.5 grain Laser pellet I should get at least the Beeman rated velocity.

 

My average accuracy with the favoured pellet is .25" for 5 shot groups at 10 meters. Beeman uses 3 shot groups at the same distance and they state .20” ctc accuracy. My accuracy seems about the same as that found by Beeman.

 

Overall I found this particular HW40 to be very comparable to the printed Beeman data.

 

 

 

MOUNTING OPTICS

 

Mounting optics on the HW40 is a very simple task due to the standard 11mm scope rail integrated into the frame. The rail is of sufficient length to mount red dot sights, pistol scopes or rifle scopes. I have mounted a Millet SP-1 red dot, Interaims OneV30 red dot, Nikko Sterling 2X pistol scope, Bushnell Sportsman 3-9X rifle scope and an older Sportsview 3-9X rifle scope. I had no problems mounting any of these optical sights.

 

My favourite optical sight is the 30mm red dot, mounted at the back of the rail. This gives a weight and balance that I find quite nice. With the red dot there is no concern for eye relief so shooting with an isosceles hold or crunched up taco hold can both be done with this same sight.

 

Shooters have often asked if the HW40 scope rail is strong enough to allow the pistol to be cocked by pushing on the optical sight or mount. I find the rail to be very sturdy but I still prefer to push on the two flat spots located on each side of the rear sight. I simply cup my hand over the scope tube and push on one side with my thumb and the other side with two or three fingers. Occasionally I put pressure on the rear mount when I get lazy. After several years I still have not had an optical sight come loose or damage the rail.

 

 

 

 

 

POWER PARTS - Seals & Springs

 

Since the HW40 is a single stroke pneumatic, there is no need to open the pistol for tuning or custom lubrication. The pistol will function for many years with very little maintenance needs.

 

Breech Seal

Out of curiosity I tried a #009 nitrile o-ring in the HW40 and it performed the same as the original factory o-ring seal.

 

 

The o-ring chart at the local “gasket & seal” dealer showed the #009 seal to be .208"ID x .070" thickness.

 

For a few of years now my HW40 breech seal has been shimmed with a couple of turns of dental floss underneath. This makes a tight contact with the barrel. The floss was left in place when I installed the various #009 seals.

 

A #009 nitrile Quad Seal was also tested as a breech seal in the HW40.

 

 

 

 

 

 

Velocities seem to be about the same. This is also what I found with my HW45 but it's definitely worth trying the Quad Seal to see what it does in your specific pistol.

 

Piston/Pump Seal

For lubricating the HW40 piston seal I use Crosman PellgunOil and it has been working fine for over 5 years. Other people prefer Mac-1 Secret Sauce or 30 Weight Non-Detergent Motor Oil.

 

I usually apply two drops of lube to the open piston/pump body approximately every 4 months or 2500-3000 pellets. I only had to disassemble to lube once because the seal had dried out and needed more direct attention. Applying the lube to the open piston body usually gets the job done. Propping the pistol, muzzle up, for a few hours after lubrication will help get the lube to the seal. A drop smeared onto the open piston body helps reduce friction on the compression tube. For maintenance purposes, a drop of lube should also be applied to each pivot area on the pistol.

 

Piston seal removal instructions:

1 - Open pistol.

2 - Loosen the 2.0mm allen screw located at the top of the piston rod (on end).

3 - Push out pivot pin for piston/pump rod. It will tap out easily.

4 - Slide piston out of chamber. A slight pull will do it.

5 - Remove o-ring located on end of piston body.

6 - Clean out o-ring groove with cotton swab.

7 - Apply Pellgunoil oil to o-ring and apply a drop into groove.

8 - Put o-ring back on piston body.

9 - Clean out compression chamber with a soft cloth or paper towel.

10 - Smear two drops of Pellgunoil on metal piston body.

11 - Re-assemble pistol.

 

Note: Do not remove compression tube from frame. It's not necessary.

 

 

 

Internal Springs

After more than 5 years and 20,000 shots part #2440 (spring), located inside the grip, cracked and would no longer open the valve. A 5 minute procedure involved removing the single grip screw (on right side) and replacing this spring. There are a few other small springs located in the grip and throughout the pistol. The parts diagram (below) shows the springs and reference numbers.

 

 

 

 

 

PARTS DIAGRAM

 

 

 

 

 

 

SHOOTING CHARACTERISTICS

 

The HW40 is an easy pistol to shoot accurately. The lack of spring recoil, mild noise, sweet trigger, moderate weight/balance, and the ergonomics all help with achieving your full accuracy potential.

 

The HW40 is not sensitive to variations in holding pressure and hand position, like with the HW45.

 

 

 

TEMPERATURE SENSITIVITY TEST

 

Since the Weihrauch HW40 is a single stroke pneumatic, it should not be affected by slight changes in temperature. My results supported this theory.