Umarex HDR50/TR50 Z-Extension Performance Series: Preparation — Part 1

This is a sentence-close edition of Z-RAM’s original video. Product availability, links, version descriptions and planned tests retain the context of that recording.

Umarex HDR50/TR50 Part 1: the Z-Extension test plan

Z-RAM presents this video on the YouTube channel. In this video, it wants to show how the Z-Extension affects the HDR50 without other tuning—that is, without a modified pin and without a PowerKit.

There is already a video about how those two parts affect the HDR50 in combination with the Z-Extension. Z-RAM will link it in the information box above, but today it simply wants to show what the Z-Extension does. The first thing to be done on the HDR50 is to remove the valves and restrictor so that the gun is completely open.

Without doing that, the extension makes no sense, because the extension ensures that you have a larger chamber, or more space in the chamber. That would not make sense with the block in here, since it reduces the space. Of course, the first step is therefore to remove this, and also remove the valve here, depending on the version.

There will then be a shooting test with the HDR50 open, as stated, without these two valves and with the standard barrel just as it is. Z-RAM will then install the Z-Extension, and the setup will be tested again with the Z-Extension. The next step is to put in the tuning barrel and see how the Z-Extension works with only the tuning barrel.

The following step will be conversion to HPA, using the tank here with the regulator rated up to 2,000 PSI and the HPA adapter. With this adapter, you no longer need the Mamba hose; you can connect the bottle directly to the adapter and then directly to the HDR50.

With this HPA set, the sniper extension will also be installed for the tuning barrel. The whole setup will then be checked again to see what results it produces. Z-RAM will shoot the Z50 projectiles; you already know them.

This time, Z-RAM will make the opening at the back for the Z-Extension with the grinder here. It has already shown in a video how you can do this with a standard file, and it will link that as well. This time, however, it will use the grinder. It is faster, and it will briefly show the process.

You can buy all the parts shown here, except for the HDR50, in Z-RAM’s shop at www.z-ram.net. As stated, here are the bottle, regulator, adapter, tuning barrel, extension, Z-Extension, modified pin and PowerKit. The modified pin and PowerKit are not being presented in this video, but Z-RAM also offers them in its shop, along with various other items for other markers. Be sure to take a look around.

All tests will, of course, use a fresh CO2 capsule. Bear in mind that it is pretty cold here: five degrees at the filming location, without heating or anything else. That means it is pretty cold here. The CO2 capsules are cold, so the results will all be relatively low. Consider the results in relation to one another and take that into account when forming your opinion.

Of course, the whole thing will be documented with a chronograph. First, Z-RAM will show how these valves will be removed and how the hole for the Z-Extension will be made with the grinder.

Umarex HDR50/TR50 7.5 J version: opening the housing

This is the 7.5 J version of the HDR50. As most of you know, there is also an 11 J version. They differ in their valves, which Z-RAM will show again in a moment. It now wants to show how to remove those two valves and make the hole for the extension.

Some preparation has already been done: the screws have been loosened so that everything can be shown faster in the video. Otherwise, the weapon is still unmodified and is the standard 7.5 J version.

The screw here has now been loosened. Z-RAM takes this off to reach the inner workings. It first pulls out the barrel, then also takes out the standard barrel and the spring. It can then take this part out, and then this part.

The screws here have also already been loosened. Simply loosen all the screws you can see, and then use a thin screwdriver to pry the housing open a little so that you can reach the inner workings.

This is what it looks like. It is best to take a photo before continuing, preferably also a close-up of this spring, and this spring, and this spring. There is a spring underneath, too. These can fly out quickly, leaving you unsure how they were fitted. Take a few photos, disassemble everything slowly, and remember what went where.

Next, this piece is taken out. Be a little careful here, because the spring is under pressure. That can also be put aside. Ideally, everything stays as it is here so that there is no lengthy effort to work it out later.

This is the bolt, and the pin is also inside it. If you want, you can install the PowerPin from the PowerKit here, which will give you additional energy. However, as stated, this video simply shows how the Z-Extension alone affects the HDR50. You can see how it works in combination with the PowerKit or a modified pin in another video that Z-RAM will link. You can also find all the parts in Z-RAM’s shop.

This is not needed for now either, so it is put aside. There is a brass screw at the back. It is loosened with a pair of thin pliers, although special keys are also available for it.

Umarex HDR50/TR50: 7.5 J and 11 J valve differences

Here is the thick block in the 7.5 J version. Some call it a restrictor, some call it a valve block: many different names, always the same thing.

There is then a valve at the back, inside here. It is hard to see now—right down here, at about this height. It is a valve, a kind of round part, but it is only in the 11 J version. In the 11 J version, there is a valve here, and this block is a little smaller, almost half the size. As stated, however, it has this valve.

In the 7.5 J version, this valve does not exist, but there is a larger block. This part makes the chamber space smaller, and this part reduces the incoming air.

The block will now be removed. Since this is the 7.5 J version, there is no valve in it either. Once the block is removed, this is an open part. In its open state, the part is constructed the same way as the open-state part of the 11 J version.

If you are looking to buy an HDR50, have found one and plan to open it completely, it really does not matter whether you buy the 7.5 J or the 11 J version.

Keep in mind that not everything shown here is allowed in every country. You have to find out whether you are allowed to carry it out in your country. This is not legal advice; Z-RAM is simply showing what is possible. In some countries, it is allowed, unregulated or forbidden; in other countries, it is forbidden. You have to make sure for yourself that you are on the safe side.

The block here is now to be removed first. Small protrusions hold the block in place. The block is pushed through here with the screwdriver. This will break the small protrusions at the sides, and the block will come out. Once you have done this, you can no longer use the block; take that into account.

Of course, the warranty is void as soon as you change something on the marker. As stated, this is not allowed in certain countries.

Umarex HDR50/TR50 block removal and reassembly

For this, you need a screwdriver that fits through here without having to force it in, so that you do not damage the O-ring or anything else. It has to pass through perfectly while remaining relatively stable. Like this: hit it with the hammer until the block comes out.

This is what the part looks like. It only reduced the space in the chamber; it did nothing else. As stated, there is no valve in here. The 11 J version has a valve here, although older 7.5 J versions also still have a valve. You can then unscrew it with a long screw. That screw is also included with the corresponding PowerKit if you ordered it; one of those long screws is included.

You can turn the screw into the valve and then simply pull it out. Alternatively, the valve has this opening, a slot for a screwdriver, so you can insert the screwdriver and unscrew the valve. In any case, make sure this is completely open at the back.

This now needs to go back in here. The bolt goes on it. This piece is in place; the spring is stretched. This part is in here. It goes back in with the narrow side toward the drum.

To install the Z-Extension, you do not have to open this up. You only have to open the plastic casing and mill the hole here. That is what will happen next.

Umarex HDR50/TR50 housing opening for the Z-Extension

The part will now be put back here as well as possible. Of course, it will not slide in because of the extension. The approximate cutting position is then marked. You may already know that from the other video.

These marks can now be extended to the other side. The extension here is about 16 mm wide, with a diameter of about 16 mm. Half is 8 mm. That means marking here to show the upper and lower limits and the width of the two opening areas.

The tool is called a milling machine here; the preceding alternative tool name is unclear in the captions. Call it what you want. Thank you.

There was a slip here. Of course, that does not have to happen to you. It did not turn out perfectly here either. In this position, while filming, this was the best result Z-RAM could achieve. As stated, it came out a little nicer with the file. If you work a little more carefully and have more time, it will also be a little neater. Take a look at Z-RAM’s other video; it is better done there.

In any case, the housing has now been adapted.

Umarex HDR50/TR50 final assembly and the next test video

Take the extension off again. The Z-Extension is always delivered with an O-ring. If it is changed more often by screwing it in and out, the O-ring can, of course, break. Z-RAM also offers replacement O-rings in its shop.

Then this part goes in here so that the spring sits behind it. That is it. It does not look as nice when it is open. It is better with an extension: it is closed, and it is all black. In Z-RAM’s opinion, if you make the opening neater than Z-RAM did, it looks okay too. It also depends on what you want to achieve with it.

Z-RAM will now screw the screws in. That does not necessarily have to be visible on camera. In the next video, it will be time to look at the chronograph tests.

Stay tuned, subscribe to the channel, leave a thumbs-up and visit Z-RAM’s shop. From Z-RAM. Thank you.

Related reading: Umarex HDR50/TR50 PowerKit.50: Joule Claims for the 7.5-, 11- and 13-Joule Versions.

Current products — separate from the historical presentation

Z-RAM Firing Bolt + Power-Pin + Z-Extension for Umarex HDR50 TR50 7,5 & 11 Jo. | Exportventil | 25-35J+

The current HDR50/TR50 set contains a steel firing bolt, Power-Pin, Z-Extension and O-ring. Its listed 7.5/11-joule starting versions are distinct from other versions. The linked standalone Z-Extension is already included here, not a necessary extra; no complete marker is supplied.

View the current offer

Z-RAM Z-Extension Tuning chamber-extension for all Umarex T4E Typs & FSC/TCP

The standalone Z-Extension offer contains the chamber extension and its O-ring. It is useful when buying that component separately, not as a compulsory extra alongside a set already containing it. For FSC/TCP use, the product identifies a separate adapter requirement.

View the current offer

Important Legal Notice

Laws and regulations governing the purchase, possession, installation, modification, and use of the products described on this page vary by country, state, and local jurisdiction and may change. Before purchasing, installing, modifying, or using any product, you are responsible for confirming that it is permitted in your location and for your intended purpose. Product availability or delivery does not mean that purchase, possession, installation, modification, or use is lawful in your jurisdiction. Z-RAM does not provide legal advice, and the information on this page must not be treated as legal advice. If you are unsure, contact the competent local authority or a qualified legal professional.