Weihrauch HW35 Customizing Aufnahme Seite Hawke Frontier

Weihrauch HW35 tuning and modification

Weihrauch HW35 – I’ve missed it a lot in the last years.

Why is Weihrauch HW35 so important to me?

The first air rifle I bought myself was a Weihrauch HW35. I bought it following the recommendation of a former colleague. That was the start of the whole madness.

I had chosen an export version of Weihrauch HW35 with a walnut stock at the Frankonia branch in Würzburg. It was an unbelievably great air rifle. After one year I sold it again. Not because I was unhappy with it, but because I needed money to buy a new air rifle. I wanted to offer variety to the few viewers of my YouTube channel at that time, so I decided to take this drastic step.

This decision haunted me for years. In 2019 it was finally time, after nearly four years I had to have a Weihrauch HW35 again.

Weihrauch HW35 could be even better

At the Hunter Field Target and Field Target Training Camp 2019 in Kölschhausen I got in touch with Ferrobell. I was given the opportunity to ask him for a small project.

I shoot my Weihrauch HW35 with a rifle scope and not with the open sight which I’ve removed. Since the barrel of my Weihrauch HW35 looks somehow incomplete without the sight, I asked him to build me a nice barrel sleeve with a barrel weight.

Ferrobell’s self-designed and modified Weihrauch was voted Weapon of the Month at CO2Air in August. There I saw his version of HW35 with a self-made barrel weight.

The project

I must say, I was incredibly happy that he accepted to do the project. After all, Weihrauch HW35 is a particularly important air rifle for me, and I associate several good memories with it.

Ferrobell has promised me that he will make some optimizations and tuning adjustments since he takes the air rifle apart anyway. Not performance tuning, but improvements of the trigger and barrel.

He kindly agreed to document his work with pictures and notes. This is also the reason why there is this great review today. The result is a tuning and customizing guide or a suggestion for it. I’m proud to present it to you on my blog.

Have fun reading it!

Tuning and customizing of Weihrauch HW35

Before the modification began, the consistency and performance of Weihrauch HW35 was checked. The chrony test was performed with H&N Field Target Trophy 4.51 mm pellets. I use these also in my Steyr LP50 RF.


The barrel weight of Weihrauch HW3

Ferrobell has designed a new barrel weight and produced it on a lathe.




The finished barrel weight for Weihrauch HW35 is pushed onto the new barrel sleeve for testing. The barrel weight is adjusted and can be slid 5 mm over the carbon barrel sleeve to provide a clean finish.


Ferrobell dyed the barrel weight five times with Birchwood Casey Aluminum Black. The result is not satisfying.




As recommended by Birchwood Casey, Ferrobell applied Birchwood Casey Wax to the barrel weight. However, the result is also not convincing.


The next approach to optically improve the barrel weight was to use Ballistol. Even with Ballistol, the result wasn’t better.



So, the barrel weight was painted black with synthetic resin vanish.


Now it’ s time for the tuning. This doesn’t mean an increase in performance, but an optimization of the shooting performance.

System-Tuning of Weihrauch HW35

Ferrobell prepared the system for dismantling.

First, the trigger has to be removed. To do this, you have to remove the two pins. When pulling out the trigger, you have to make sure that you hold the safety pin of the trigger! It has a spring that will make the pin and the spring pop out if you are not careful.



Now it is time to disassemble the barrel. You can remove the barrel pin better when the barrel is slightly bent, because then it is no longer under tension.




The barrel is removed




The system is disassembled.




Look how greasy the piston is.




But there was no grease on the front of the piston seal.




Ferrobell cleaned the system sleeve with a rag. That works best if you wrap a cloth around a rod and then turn it.



New spring guides for Weihrauch HW35

Now we want to make a tighter spring guide. The original one has only a one-piece spring guide. Ferrobell installed a two-piece spring guide. This has the advantage that the front spring guide centers the spring in the middle. The rear spring guide also centers the spring and prevents vibrations. The white rod in the picture is a POM rod which is used to make the spring guides.

Here you can see the original spring guide on the top and below the new two-piece spring guide.




The original spring guide has a diameter of 13.6 mm. The new spring guide has a diameter of 14 mm and fits tightly.






The spring ends have to be finished to make them run smoothly.








Ferrobell then disassembled the trigger, polished all the latches, and greased and reassembled all the parts.

Vortek piston seal for Weihrauch HW35

The original light-colored piston seal is removed, the Vortek seal is put on and greased with TBT MoS² grease on the sides. It is important that you never touch the front side with the grease. It has to stay absolutely clean. Otherwise, this can lead to the well-known diesel effect which causes the grease to burn and increases the pellet speed.


The two seals in comparison. The original seal is cast and the Vortek seal is lathed. The Vortek piston seal has the advantage that it seals better.



The piston is a bit thicker at the end. The surface is also coated with MoS² grease. The spring is sprayed with chain grease and is inserted together with the spring guide.


Sling swivel for Weihrauch HW35

I want to add a nice rifle belt to my Weihrauch HW35. Therefore, I need a new clamp for the front sling swivel. The 15 mm clamp from the original barrel is now too small for the 19 mm barrel sleeve. Therefore, Ferrobell built a new clamp.

He used a 1 mm thick piece of sheet metal and prepared the quick browning in a cup.





He cut the sheet metal piece, derusted and bent it. Then he drilled two holes for the screw.







Ferrobell filled the cup with some quick browning and put the clamp in there. It turned a nice black color. Then he rinsed it off, rubbed it dry, and put Ballistol oil on the browning. The quick browning has colored the metal nicely, but the result could have been even better. Maybe the clamp should have been polished first and then put into a bath of hot black oxide.

Assembling Weihrauch HW35

Then it was time to reassemble my rifle. This is how it looks now…

from the front…






from the back…






  and from the side.

I hope you enjoyed my review. If so, please leave me a short feedback, then I will try to get some more reviews from Ferrobell. But there’s no guarantee. He is very busy, and a documentation of the work isn’t easily done in a few minutes. It really is a lot of work.

If anyone of you has an advice for an optically matching rifle belt for my HW35, just wirte me an email or comment. It would complete the hunting look of the HW35.

I thank Ferrobell for his excellent work. I’m still blown away how my Weihrauch HW35 looks now.

And I thank you for reading!
See you next time!
Best wishes!

Interesting link:

Do you already know my international YouTube channel? HERE you will find videos of more powerful air rifles in English.

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