Review: PDI Variable Hop-Up Chamber with Cylinder Head for Marui VSR-10 / G-SPEC

Troyad21

I just thought I'd throw up a first impression review for the following piece of kit (I will update it in a week or so with my final verdict after I've used it out on the ground) : http://shop.ehobbyasia.com/pdi-variable-hop-up-chamber-with-cylinder-head-for-marui-vsr-10-g-spec.html

Ok first things first. This item is only on the market a few weeks and there are no reviews online that I have found (the main reason I'm doing this )
Also, there seems to be an awful lot of uncertainty about its compatibility with the stock VSR cylinder or any other cylinder bar a PDI one. PDI say that you need to use their Raven or Precision Cylinder to use this set >
http://www.x-fire.org/vsr10/e.vsr_chamber.html

After reading this I was really unsure and due to sheer desperation for an AEG style hop up unit that can accept a soft bucking, I took an expensive gamble. Luckily enough it paid off as it actually fitted my stock VSR cylinder better than the original cylinder head and the Laylax/PSS10 Dampener Cylinder Head I had previously used.

From what I can see, PDI are basically just trying to get you to buy their products only(which would be grand if you were Sean Quinn, oh wait :rolleyes: )for the people that don't get that one, PDI parts are extremely expensive.
Think Magpul for the Airsoft sniper world. It was over €100 euro incl.shipping :eek:!!! Now lets get down to the business end.

Contents:

The set comes in a small package with everything packed away in tiny bags. Be careful not to loose any of them as you don't get any spare components. You get the following:
x1 Hop-up Chamber
x1 Tapered Cylinder Head
x2 20mm O Rings
x1 10mm O Ring
x4 Grub Screws
x1 Soft W-Type Rubber
x1 Nub (You will need to cut down to size depending on what AEG barrel you use)
x2 Mounting Allen Screws (Not necessary if you hold onto the stock ones)
x1 Small Allen Key
x1 Installation Guide (Engrish :P but diagrams are easy to follow)

Installation:

Even though the installation guide is hard to understand, it is actually quite easy to install. Just follow the diagrams and you'll be fine. The only parts that remain from the stock setup are the mounting allen screws and the hop-up mount block itself.
There are 2 barrel stabilizer grub screws that hold the inner barrel so it doesn't twist or move within the chamber which is a great feature, as I'm sure everyone has had issues with barrels twisting and throwing the BB's off left or right(Not good when you're only firing one round at a time and waiting ages in a position only to miss your target and give away your posish :mad:) Once the unit is installed it is really sturdy and does not budge. As I said previously, the cylinder head went on like a glove.
PS. You will need to remove the stainless steel pin from your the top of the stock cylinder to install this part.
Here's the link I used to help me http://youtube.com/watch?v=2ynrxBi7Sg0

As far as problems go, I had none at this stage.

Operation:

All the info I have read on this so far has given no explanation on how the unit actually works. Here is what i can make from my experience.

1) There are 2 steel independent arms with grooves on the inside tip that press down on the nub which therefore push on the W shape on the rubber/bucking.

2) These are then securely held down with the two 20mm O-rings.

3) Two grub screws are installed either side of the BB feeding hole.

4) These in turn push each arm (independently) up reducing the affect of the hop up.

5) These 2 independent arms are used to fine tune the spin the hop up adds to the BB. So if you are firing slightly left or right you can adjust either one accordingly to cancel out the affect.

6) The W shape protrusion on the rubber seems to work by putting even pressure on both sides of the top of the BB as it passes through the chamber.Therefore creating a more effective spin and more stability as it passes through the barrel.

Testing:

During testing and zeroing in I was amazed to see the vast improvement in my VSR's range and accuracy from my previous hop-up and cylinder setup(Laylax PSS10 Airseal Chamber for AEG barrels and Dampening Cylinder Head)
The main thing I noticed when I pulled the trigger, was that the BB's actually glided through the air and were really consistent. I did find that it is slightly louder with the PDI cylinder than with the Laylax one. Not too much of a problem as the G-Spec is quiet enough. During this stage I noticed a problem with PDI's design.

Problems:

During testing I noticed that my VSR started to mis-feed and after a minute or two of messing about with it I realised that the BB's were falling back into the receiver as I was cocking it. So I took the rifle apart again and noticed a large flat head screw on the side of the chamber.
After some fiddling around I realised that this screw was attached to a small spring which held, believe it or not, a BB?!
I then realised that this "BB" was basically there to stop the(real)BB from falling out of its housing back in to the receiver. After having a look at this piece I noticed that the "BB" was kind of worn down from the cylinder head rubbing off it as it engaged the hop up chamber. I then thought why not try a heavier BB as a replacement as it would probably be more resistant as it would be denser. So after reinstalling the "BB" and spring, and tightening the flat head screw, and putting it back together I had no more issues with misfeeding. I'm not too sure just how long a regular heavier BB will hold up in it, so for long term use I plan on getting a 6mm steel BB as a permanent replacement as I think that would work a treat. I think this was just lack of long term thinking on PDI's part as they were probably spending most of their time on the instruction manual
The only other problem, if you could even call it that, is the taking away of the hop up adjustment arm which the VSR is known for. With this chamber you have to adjust the hopup with the provided allen key using the method that I mentioned in the operation section. Personally it doesn't bother me too much as I have my own hop up setting that I love and I stick with that no matter what.

Conclusion:

The problem I found with the Laylax/PSS10 equivalent was that you can only use the bucking/rubber that comes with it and that rubber is a hard type which only suits around 400+ FPS so it isn't great for optimising your setup with FPS the limits in Ireland. If you are in the market for a quality piece of kit that will allow you to use an AEG barrel with a soft type bucking in your VSR, then this is the set for you. Personally I think it is really over priced but at the end of the day, this is Airsoft and alot of the gear we use is overpriced.
In comparison to my previous hopup setup it wins hands down.

My Setup:
Just so people know I'm not talking through my arse

Tokyo Marui VSR G-Spec:


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Custom CADPAT Paintjob
M3 Replica Illuminated Scope
Harris Bipod
PDI Hopup Chamber and Bucking
PDI Tapered Cylinder Head
PDI 110 Spring
x2 PDI Barrel Spacers
510mm Tanio Koba AEG Twist Barrel
Drilled Silencer to accommodate longer barrel


So much for a quick review This is a f***in' novel
Hopefully this has cleared up any doubts or questions people have about this kit and its compatibility with other parts.
Thanks for holding out until the end