Buzz Bee Berserker Internals & Overhaul (VERY PIC INTENSIVE)

Hey guys,
So when in Malaysia in the summer hols of 2011-2012, I found a whole bunch of Berserkers sitting in several TRUs. I also spotted stuff like Rads 12s, Rogues and Tetra Strikes etc but I was tight on space so I only managed to get one Zerker and 2 Jolts. Besides, of all of them the Zerker was the one I most wanted (as with the Jolts).
Anyway, I've only recently decided to properly mod it, and I decided to do a full writeup on how I did mine.

NOTE: Sorry for the terrible pics, I used my iPod Touch.

TOOLS REQUIRED:
-Screwdriver (of course)
-Hacksaw (dremel works just as well)
-Dremel
-Hot glue gun
-Drill
-Ruler
-Pen/Marker (for marking barrel lengths)
-Claw Hammer

MODS:
-Rebarrel
-Handle Replacement
-Extra Spring

*INTERNALS*


Shot of the (mostly) stock blaster. At this stage I'd removed the dart pegs, added a small tac rail and sliced down the rocket launcher for a coupler.
The orange shell pieces can be removed when their respective screws have been removed.


Open. There are a number of screws, one of which is under a sticker. In the first pic you can see the hole I punched with a screwdriver to get at it.
There are four larger screws which go into:
-Top right screw port
-Bottom right screw port
-Left most screw port
-Middle upper screw port


Close up of the air tank area. So far as I can tell it's basically a 4B with lever trigger.


Close up of the plunger, turret and rotation mech. The large, short spring pushes the plunger tube against the turret.


The massive turret.


The dual triggers. Note how the airgun trigger (front) has popped out of place. I haven't modified it - it pops out of place when stock. It can make reassembly annoying, but it will be rectified later.


Close up of the spring holding the lever trigger in closed position. It's a pain to put back into position once removed, so be warned!


The turret and entire airgun assembly come out as one. This is because the airgun barrel supports the rotation mech and turret.


Without the airgun and turret, the shell is suddenly almost empty.


Exploded view of the rotation mech. In order from left to right:
-Main rotation mech piece (links to plunger assembly)
-Gear thingy that latches to turret
-Spring which compresses turret outwards against shell (for rotation mech) (surprisingly strong)
-Turret (duh)


Turret from a different angle.


Down the front of the turret. Note how I've epoxied on a 25mm coupler and removed all the air pegs.


Turret with inner cylinder thingy removed. There are 5 screws holding it in, but they're easy to get at.



*Rebarreling*

CONSUMABLES:
-Barrel material of choice (minimum 1m worth, probably better to have 1.5m+) - in this writeup I used 16mm UPVC because it fits stock darts nice
-Hot glue

*NOTE* Anywhere where UPVC is mentioned can be replaced with your barrel material of choice.


I used this much UPVC because it's all I had. I think you get better performance from longer barrels than what I used.

Before cutting into the turret, remove the pegs. This is easy, just drill down the hole in the base of the turret. Don't enlarge the hole - you might mess up the seal. Once the peg's out, clean it up with pliers, screwdrivers, whatever. Repeat for the rest of the air pegs.


First of all, cut your stock barrels around the mark. I think it's just under the 1cm mark from the base of the turret.


Part way through it. It's really tedious with a saw, but I don't trust myself with a dremel cutting disc (and I love using saws).


Completed cut.


You can see the height differences here. On the right is the base you just cut out, on the left the rest of the stock barrels.


16mm UPVC fits in tight in the base 'cups'.


I cut my barrels to around the 5cm mark (2"). More popular lengths are 3" (7-8cm) but 5cm was the longest I could do (ran out of UPVC).


Fit stock darts pretty good.


Next, cut the remainder of the stock barrels just underneath this part. You don't want to cut above because you'll lose the screw ports, which are essential to the blaster.


Half way through. Note how the inner ring is also cut. This is ok - the screw ports are still intact.


Complete. On the right is the useful part, on the left some useless plastic. Go ahead and make it into a paperweight or something.




The section you just cut off should still fit on the giant cylinder. These are why the screw ports are essential - they hold the turret onto the rest of the blaster.


The waste plastic from slicing the turret apart. It was more impressive in real life.



Cutting out barrels...

Test fitting barrels. They fit real tight, but I didn't like it.


All 20 barrels cut ready.


If necessary, sand one end of the UPVC so it fits nicely in the base without being too tight.


All twenty barrels test fitted.

There are two methods of rebarreling. The first is sanding the inside of the cylinders on the front part of the turret out so they fit the new barrels, like so.


I couldn't be bothered though, it took too much time. So instead I did this.

Cutting off segments of the top turret part, the remainder of the stock barrels would form 'cups' which would hold the barrels in place.


All cut down.


Sand the teeth down like so.

Now when I tried assmebling it as is, it didn't work. The cups were too small. If you're not using UPVC you might not need to do this, but sand the cups out like this:



Close up. Right is sanded, left unsanded.


Test fit like so. The top ring should not be trying to push the UPVC outwards.


Complete! Even without being glued and properly assembled this is quite menacing.


Begin gluing in the barrels to the base. I used hotglue. Make sure it's an airtight seal around the barrel.


Half way there...


Complete!

Now for the top piece....

It should fit in neatly like this.


Test fit the entire turret (blutack the front part to the barrels) to make sure it fits fine in the shell. Push the base of the turret back into the plunger outlet.


Like so.


Lift the turret assembly out without moving the front piece and glue it.


If necessary sand the outer edge of the turret so it doesn't catch on the shell.

The rebarreling is complete!
Reassemble and test fire the turret. If that's all you wanted to do go ahead and close this window. If you want to do even more, continue.


*Handle Replacement*

EXTRA CONSUMABLES:
-Sacrifice handle (I used LSFG)
-More hot glue
-Epoxy (strongest one possible)
-Several screws
-Hot glue/Epoxy putty (optional)

Most of you know how childishly small the Zerker's handle is. We're going to fix that.


LSFG handle compared to the Zerker's. See how much larger it is?

Cut the trigger of your LSFG handle down, and drill a hole in it like so:

I used I think a 1.5-2mm drill bit.
A wire goes into the hole which releases the plunger catch.


Test fitting the trigger.


Begin cutting off the Zerker's handle like so.


And decapitate it at the trigger guard. Don't cut the trigger guard off though, it's useful. It holds the triggers on rails.


Cut the LSFG handle down to this.


Test fitting, no glue. You'll need to do some trimming on the Zerker shell and LSFG handle to accomodate for the trigger.


Glueing it with hot glue. This is merely to hold it in place for the rest of the mods.
Once it's in a good place epoxy it like your life depends on it.


The way I attached the handle resulted in the airgun trigger being too far back. This is an easy fix, just trim the Zerker shell so you can move the trigger forward, and hot glue the rod it is attached to. This alignment the air fully releases as the airgun trigger just touches the springer trigger.

Once the epoxy has dried, you'll want to reinforce the handle by securing the handle to the body of the Zerker with several screws. This is essential as I've had the handle break off with just epoxy. Make sure not to damage any internals with the screws or screwports. Unfortunately no picture of this step, but you get the idea.

You can use hot glue or epoxy putty to fill in any gaps, and reinforce the handle-shell join.

Once the epoxy has fully cured and the screws are all in, you're done! Your Zerker now has the handle of an LSFG (or whatever you used) and not that useless tiny stub it used to have.


*Spring Addition*

EXTRA CONSUMABLES:
-C-756 Spring (Bunnings, about $7)


Remove the plunger from the shell. It's a direct plunger (yay!).
Take careful note of how everything fits together.


Using a claw hammer pry off one of the green caps. It'll come off eventually.


The plunger system disassembled.


I added a C-756 spring (from Bunnings) as it was the best fitting spring I had in my box of springy fun. The load of it is less than an NF's spring, and it fits perfectly inside new gen NF springs.

*Other Stuff*

I didn't play with the seal because it is already great (almost perfect). Buzz Bee were also kind enough to pad the plunger with a rubbery thingy. It's really tough and probably actually absorbs impact. I was too lazy to replace it in any case.

The plunger-outlet-turret seal is also great so I didn't play with it.

By now you're probably wondering why there's no writeup for modding the airgun. I didn't do this because I'd already modded my airgun, and the process is almost identical to that of a 4B (which is all over the interwebs). The only precaution is not to cut the barrel too short because it supports the turret and the rotation mech. Other than that, it's basically:
-Saw off the tip
-Slap on a coupler

If you want to attached a shoulder stock (for ease of priming, aiming and stability), I suggest a look at iamthatcat's writeup on attaching a Praxis stock to a BBUMB handle. The Zerker's handle is pretty much the same so the same processes can be applied.

Not pictured, I drilled out the Zerker's plunger output hole. I used a drillbit barely larger than the outlet. The important part is that there's a smaller orange piece within the plunger output piece which restricts airflow, so drilling it out slightly increases ranges. Beware not to mess up the seal though.

Another mod you might want to consider are attaching sling points. This is easy, just drill holes in the shell and put in eye bolt thingies. Hot glue if necessary for reinforcement.
I've done this to my Zerker (not pictured). It's really quick and simple, and allows the use of a sidearm. Why you'd need a sidearm with the Zerker though is beyond me.


*Completion*

Once everything else is done, relube the plunger o-ring (as usual), and if you want relube the pump o-ring. I didn't bother.

Now reassemble your Zerker (after the various glues dry/cure fully).
For some reason mine was reluctant to be reassmebled but with some persuasion (ie brute force) it submitted and closed.
If you've done everything right you'll end up with one beast of a blaster.



My ranges: Unconfirmed - these are based off velocity/impact tests indoors.
Turret: (PTG)
-50-55ft (15m+) with Whistlers
-60ft+ (18m+) with Streamlines
(ATG)
-Probably looking at 70-80ft (22m+)

Airgun: (PTG)
-Typical 4B ranges - 40m quite easy with the right dart-barrel config
(ATG)
-Probably well over 200ft (~60m)

I have no doubt that the turret could be pushed to 70ft or even 80ft (PTG) with the right springs, dart and barrel combo.

And that's the end of my first proper write-up.
Any comments, suggestions or questions(other than 'get a better camera')?

The turret can actually get up to 80ft 15-25degree angle. :D.

Epic write up. Directory it goes :D.