Project Dominator

[paran]

About a month ago I bought from a forum member
(thanks Diana for the prompt transaction and for the new toy you have sent me...)
a full 1250 DOMINATOR in my favorite caliber, 6.35mm, which was missing the original airtank,
and an airtank from a Cometa Lynx with it's regulator.
The initial thought was a complete improvement of the rifle,
where ever that was possible and the placement of the COMETA airtank "upside down",
lower and further back. As it was August, a very busy time workwise,
the "upside down" placement was left to be done in the winter...
Initially an adapter was built that connects the housing of the original fire valve with the COMETA regulator.
That was built  from phosphor bronze (a piece from an old boat shaft that was lying around and was free...) using a lathe.



This adapter, obviously, nullifies the Dominators' regulator, doubling (and little bit more) the space volume between the firepin and the COMETA regulator. The main hole was made 8mm for unhindered flow and I must confess that because of the small size of my lathe and because of my lack of craftsmanship the adapter is not completely straight, so the airtank is slightly offset (1.5mm) on it's top end.



See the adapter in place, between the fire valve and the regulator:







The small hole of the original regulator was sealed instantly with an M3 screw.



Obviously, the only regulator remaining is the one from the COMETA.



Next was the improvement of the original block



Truth be told, I had studied a lot the internals of the 1250, so I knew exactly what to expect:



The rifle had already holes drilled through from the bolts that closes the block
and their place was taken by stainless M3 bolts and nuts.
The first thing I did was to change the "weak" M3 bolts with M4 bolts,
making the necessary threads to the blocks' aluminum alloy.







The plastic blade from the original trigger was not to my comfort,
and the way it is designed it can not be improved to offer a soft,clean operation.
So I manufactured a carbonfibre blade, wider (11.5mm) whose engagement
with the mechanisms' "anchor" is possible with a small (Φ 6mm) stainless roller.









The stainless mini roller was brushed accordingly:



Next was the "anchor" of the mechanism,
whose shape was modified accordingly to work with the roller.
Obviously the hole of the original setting screw, which was nullified, was closed.
The touching edge with the hammer was sliced, in a way that would improve the feeling
but also it would "clean" the disengagement point:







so the trigger now has a clear, short first stage and extremely smooth and clean disengagement





The barrel porting was done properly from the previous owner,
so all I had to deal with was polishing which was done using a Dremel





Next was the transfer port, which proved to be a bit of a fuss.
It is hidden from a "plug" with a steel ball in a aluminum housing.
With patience, using my dental airtool I cut the ball and removed the aluminum piece of the plug.  
The original transfer port of the 1250 was measured to be 4.5mm.
Initially it was opened to 5.5mm and it was plugged with a M6 stainless headless screw.
Then, because I wanted to use the limits of the block, the port was opened to 6.7mm,
which is absolutely on the limit.
It was plugged with a M8 stainless headless screw and sealed with a "moderate" Loctite.
If you try it, it is better to open it up to 6.5mm.
In the first photograph is the primary M6 headless screw.















The route from the fire valve to the transfer port was opened at 7mm and polished using the Dremel



The last thing that was done in the block area was a bit of filing to the "middle" piece of plastic of the safety
(which was not automatic from the previous owner), in way that it would sit firmer in the positions ON-OFF.



After that I focused on the fire valve



then I widened the outlet diameter of the fire pin at 6.5mm (you can't do it more easily...)



I replaced the original centering component,which was filed from the previous owner,
with a star-shaped one which I made from stainless steel and it ensures even better flow.





In the next photos you can see  the fire valve components and the fire pin in place





At this point, after a modest lubrication,I reassembled the rifle and I filled it with air.
After about 20 dry shots, I heard a leak from the firevalve.
Immediately I disassembled the rifle and found a minor scratch
on the surface of the hard white plastic that seals the fire pin.
Using special magnifying glasses I discovered that it was a tiny snag (left in the first photo...)
I immediately replaced the seal with a size viton 7x2.5 mm o-ring and everything was OK.







Next was the rifle stock. Because it would be temporary
(as said, during the winter the rifle will change again)
I chose to make it out of cheap plywood.
The rectangular block and the multiple layers saves you from excessive digging later on.
I chose not to make anything adjustable, since the stock was tailor made to my liking.
The rough work was done using power tools,
and the rest using the Dremel with barrel-shaped sandpaper and of course by hand.
Here it is before snading.























Truth be told,the laminated stock the lines look great and besides that they give a 3D feeling...
I forgot to mention that the trigger guard is a carbon fibre "blade" glued to the wood.











I chose a different from usual place for the pressure gauge and the fill, which is very convinient





The "insides" of the stock, as already said was much easier to be shaped compared to digging the wood out







The stock is attached to the rifle with a single M5 bolt,the front one of the original 2.
I made in my lathe a grommet for the only bolt of my rifle stock.





Now it was time for the shroud.
From the very start I had decided to make a full shroud with an integrated silencer at the front.
Because of small clearing between the barrel and the air tank,
there was only one option for the shroud. To be offset.
And the offset was my only option, in order to have enough internal shroud volume,
meaning having 25mm outer diameter, which is the minimum for proper functionality.
To reduce costs, I did no chose to go with carbon fibre tube, but with an aluminum one,
marine grade, 1mm wall thickness, which was for free.





The aluminum offset innards of the shroud were made in the lathe,
and you can see them here with the barrel (outer diameter 15mm)
and with the marine grade aluminum tube...



They are offset drilled





The rear plug of the shroud was made from the short piece of aluminum (23mm length)
which can be seen at the right in the next photo.



The front plug-silencer was made from the long piece (13cm).
The whole formation was made using the excellent air grinder Nakanishi ECOMO
equipped with a "thick" carbide bit.







I made the air chambers in a 3D, random shaped design







The front plug is fixed to the barrel with two M5 headless screws















and the length of the first chamber was made intuitively









using the lathe I formed the "facade" withe the offset 7mm hole



At this point,I glued the rear plug to the tube using cyanoacrylate adhesive
and the shroud was installed on the rifle for the first time,
and I discovered that an extra headless screw is needed in the rear plug to prevent it from spinning...





In the meantime the stock was painted with a "dirty" grey camo and was sanded and varnished
using a car satin varnish (IVAT, similar to the one we use for our spearguns).
The shroud was painted in a black matt color,
after making four 5mm holes at the rear underside so it could "breath".









































































As said,the shroud "breaths" from four 5mm holes and is secured on the barrel with a 5mm headless srew.
Between the shroud and the block I installed a 15x2 mm o-ring





At this point I installed a stainless M5 thread at the butt of the stock
in order to insert a screw to help me in painting it.
Finally I cut a piece of rubber and made an anti-slip butt-pad.







The rifle is 113cm in total length,weights 3640gr without the scope (3440gr without the shroud),
it balances with precision if you hold it between the block and the shroud
and was named by me one night "Lizard" but when Katerina saw it (she is a biologist, she should know better..)
she named it Rhinoceros (diceros bicornis). Black. You know, those dangerous ones with the two horns...
I am expecting soon a small Rhino sticker so I can finish varnishing and of course I am expecting the scope
which was ordered a few days ago and it should arrive soon.





The original post is here : http://wfks.gr/index.php?topic=2237.0