Michaels LGV
Reader Michael’s Walther LGV.

Part 1
Part 2

History of airguns

This report covers:

  • Setup
  • Mainspring Compressor?
  • Let’s begin
  • How to disassemble without a mainspring compressor
  • Spring guide is tight
  • Remove the piston
  • Clean the grease out
  • Looseness inside the piston
  • Mainspring is straight
  • Lubricate the powerplant
  • Assemble the rifle
  • First shot
  • Velocity
  • Basic
  • Meisterkugeln Rifle
  • JSB Exact Heavy dome
  • Discussion
  • Summary

Today I clean and lubricate reader Michael’s Walther LGV, This is the first time I have had this powerplant apart. Michael — this is the big reveal!

Setup

I need to tell you some things up front. First, In Part 2 I rated the LGV a 4 for disassembly, where most Weihrauch rifless are 10s and the R9/HW 95 is a 6. After doing this job I will increase my rating of the LGV to a 7 — as long as you use a mainspring compressor. With familiarity that might increase to an 8. And I will also tell you how to disassemble and assemble the LGV without a mainspring compressor.

Next, Michael’s rifle is a 21 joule airgun. For Americans that’s about 15.5 foot pounds. And that is almost what we saw in Part One.  The rating is a liability figure that the airgun should never surpass but could potentially reach. We saw up to 14.17 foot pounds when it was tested as it came back from Umarex USA. But it vibrated horribly. And for those who think I’m complaining about the noise, I apparently didn’t make myself clear. The vibration was felt in the head and hands. It was nasty.

Mainspring Compressor?

Why do you need a mainspring compressor? Perhaps you saw a video on YouTube where a guy took an LGV apart without a compressor. Yeah, you did. That was a lower-powered LGV whose mainspring was not under a lot of preload. The 21-joule mainspring is preloaded with about an inch and a quarter of compression. I would guess that is roughly about 100 pounds of force. When I get into disassembly I’ll tell you how to do it safely without a compressor, but you will need a helper.

Let’s begin

The first step is to remove the barreled action from the stock. That’s 4 Allen screws. With the barreled action out of the stock you are ready to remove the trigger group, spring guide and mainspring. If you’re by yourself as I was, a mainspring compressor is a must. The LGV fits into the compressor very well and all I had to do was put a flat block of wood against the rear of the trigger assembly so the compressor could push the assembly in just a bit. That takes the tension off the two crosspins that hold the trigger assembly inside the spring tube and once the tension is off they slide right out. No hammering is necessary like it is on a Weihrauch rifle. These pins are a couple thousandths smaller than the holes they pass through. If you are by yourself you can adjust the compressor slightly to just take the tension off the pins. 

How to disassemble without a mainspring compressor

To disassemble without a mainspring compressor, set the trigger end of the barreled action on a strong workbench and press down with around 100 pounds of pressure. Have a partner press out both crosspins with a pin punch. Once you get the tension off by pressing down, those pins slip right out. Can you do this by yourself? I suppose some guys can, but it’s way beyond me. But with a partner to press the pins out, it’s easy. The same holds for assembly.

LGV trigger out
When the crosspins are out and the compressor is relaxed the trigger assembly will come out of the spring tube about 1.25-inches.

Once the tension is off the mainspring just pull the trigger assembly out of the spring tube. The white synthetic spring guide comes out with the trigger assembly and the mainspring will not separate from it. I don’t know if the guide is Delrin or Nylon, but it is slippery.

There wasn’t as much grease on the spring as I thought there would be. But it did have a profound affect.

LGV mainspring
The mainspring had less grease than I thought. Still, it did the job.

Spring guide is tight

I was surprised to find that the mainspring was on the spring guide very tight! That’s what you want. This is a well-designed air rifle! I could do no better. There is also a forward spring guide that we call a top hat. It is also on very tight, plus it fits tight inside the piston.

LGV top hat
The LGV also has a forward spring guide, which we also call a top hat.

Remove the piston

Now disconnect the cocking linkage by simply lifting it out of the piston and away from the cocking slot. The piston will then slide out of the compression chamber. You don’t have to remove the barrel to remove the piston. That’s one reason this LGV earned my respect and got a higher number on the ease of disassembly. There is no good way to grab onto the piston, so I simply bumped the end of the spring tube against my benchtop, with a thick rag for cushioning.

LGV cocking link out
The cocking link lifts out of the slot without removing the barrel.

Clean the grease out

Once the piston was out I had access to clean the Tune in a Tube grease from the powerplant. The mainspring and the inside of the piston had the most grease. I used a dowel with paper towel wrapped around to remove the grease from the compression chamber. A thin screwdriver blade with paper towel got most of the grease from the inside of the piston, but I had to do one more thing. I have some 8-inch thin wooden crafting sticks and I used cotton to make a long cotton swap. That cleaned the remainder of the grease from inside the piston.

LGV swab
I made up some long cotton swabs to get all the grease out of the piston.

The rest of the interior of the spring tube was unaffected by the grease. I did note, though, that the LGV has a separate compression chamber inside the spring tube.

LGV compression chamber
A separate compression chamber (arrow) has been pressed into the LGV’s spring tube.

Looseness inside the piston

The only place were I found any looseness was inside the piston. The mainspring has some play, though I don’t know if it’s enough for a soda can shim to fit. It’s pretty small. It was packed full of TIAT though.

Mainspring is straight

I rolled the mainspring on my benchtop and could see no wobble or deflection. It looks like a new spring. The piston seal is also in good condition all around. You will note that the piston seal is smaller than the rear of the piston. That’s because of the separate compression chamber that the piston seal rides in but the rear of the piston never enters.

LGV spring straight
The mainspring is like new and so is the piston.

Lubricate the powerplant

With all the parts clean and dry I lubricated the mainspring. I used about one-tenth as much TIAT as I used before, but I made sure to lube the inside of the spring coils as well as the outside. No grease gun this time. I used a cotton swab to control the amount of grease that was applied.

Assemble the rifle

That done I put it all back together. It came apart and went back together with cleaning and lubrication in about 90 minutes. Now it was time to test it.

First shot

Michael, your LGV is still vibrationless! It does lunge forward a bit now with less lube inside, but there is no twang of any kind. I used a little more lube than I did for the HW 30S, because this rifle vibrated so much before, but I used less than I ever would have thought possible.

Velocity

Okay — the big test. Are you ready?

Basic

The RWS Basic pellet shot at an average 945 f.p.s. before I did anything to the rifle. After the first injection of TIAT it averaged  811 f.p.s. Today, after carefully using about one-tenth as much TIAT on the mainspring, the same Basic pellet now averages 910 f.p.s. for 10 shots. That’s a decrease of 35 f.p.s. in exchange for a dead quiet mainspring. But the tune is still breaking in, as I will show you in a moment.

The velocity spread before any lubrication was 16 f.p.s. After today’s tune the spread ranged from a low of 898 to a high of 924 f.p.s. That’s a 26 f.p.s. difference. But, as I told you — wait for the good news.

Meisterkugeln Rifle

RWS Meisterkugeln Rifle pellets averaged 882 f.p.s. before any lubrication and today they average 864 f.p.s. That is a decrease of 18 f.p.s. Before any TIAT this pellet’s velocity spread was 14 f.p.s. Today it ranged from a low of 856 to a high of 872 f.p.s for a difference of 16 f.p.s. I don’t know if you can see it yet, but this new tune is breaking in right before your eyes.

JSB Exact Heavy dome

The last pellet I tested was the 10.34-grain JSB Exact Heavy dome. They averaged 755 before any TIAT and 766 f.p.s. today. That is correct. They are faster today than before I used TIAT. Before the velocity spread was 15 f.p.s. After today’s tune the range goes from a low of 864 to a high of 869 f.p.s. That’s right — just 5 f.p.s. difference!

I could see that the tune was breaking in as I tested. So I shot three last shots with RWS Basics. They went out at:

926
913
928

Michael, you may get back all the velocity that was lost. You just need to keep shooting this rifle. After you feel the difference TIAT has made I don’t think that will be a problem.

Discussion

Umarex USA did a wonderful job tuning this LGV, but it needed something more that they didn’t do. It needed TIAT. Done right the rifle loses little or no power in return for smooth vibration-free shooting.

I have to say this LGV is made quite well. Many of the parts are machined well and the mainspring fits on the spring guide very tight. The only looseness I saw was the mainspring inside the piston and I think that was intentional. It was filled with TIAT after the first lube job and I think cleaning all of it out is where we picked up the velocity. There isn’t enough TIAT on the mainspring to gather inside the piston again.

Summary

I think Michael will give us the summary when he gets his rifle back and shoots it. Until then we will have to wait