DD68 Redux

DD68 Redux

Specifications
Type	Mechanical
Action	Pump-action
Barrel	6.25 inches (7.25 inches optional)
Bore	Freak inserts
Retail price	$1,080+

The DD68 Redux "68 Desert Duck Redux" or just "Redux" is a Nelson-based pump-action paintball marker produced by Steve Brett at Von Kampen Corporation and based on David Loo's DD68 Desert Duck.

Von Kampen Corporation (VKC) is located in Van Nuys, California.

Aesthetics

Redux without extended grip

The Redux design is based on David Loo's DD68 Desert Duck which was designed to look like a Colt M1911 pistol. Placing the compressed gas source, the 12-gram powerlet, inside the grip avoids the need for an external "bucket changer," contributing to pistol-like appearance.

An extended front grip is available which adds approximately 1-inch to the height of the pump handle. The extended grip is attached via four (4) machine screws. The standard pump handle which surrounds the barrel is left intact and the extended grip simply bolts on.

Design

Internal valve mechanism

The term Nelson-based is borrowed from the Nelson Paint Company and its first marker, the Nel-Spot 007.^[1][2] The basic valve design found in these early markers laid the groundwork for many other manufacturers, including CCI, to develop their own paintball guns.

The Nelson design is in-line which means that the bolt, hammer, and valve follow the barrel and form a line as opposed to being stacked.^[3]

The Redux fires from a closed bolt position meaning that when it fires the bolt is secured into the breech end of the barrel with a paintball loaded.^[4] In comparison, the bolt in an open bolt marker is not secured until the marker fires, at which point the paintball is chambered, fired, and the bolt is then re-opened.

There is no evidence showing that either design is more or less efficient than the other in the sport of paintball.^[5]

Another characteristic of the Redux that varies within the Nelson-based family of markers is that it features the original breech drop design as opposed to the bore drop variation of the design, meaning that the paintballs drop into breech, aft of the barrel, rather than dropping into the bore of the barrel. Breech drop markers.^[6]

Hammer and bolt

According to Steve Brett, aka "mOngo", the Redux uses a slightly modified CCI Phantom bolt.

In the Redux, the bolt has an extra hole drilled on the side to accommodate the field-strip lever placement, slightly rearward from the standard Phantom bolt cocking arm hole. The hole for the Phantom cocking arm bolt remains and care must be taken to line up the correct hole with the Redux field-strip lever pin, otherwise the marker will not cock correctly.

This is done for cosmetic reasons, so the field-strip lever location matches that of the original Dave Loo Duck.^[7]

The bolt is further modified by having the front taper lengthened slightly. This is done to match the taper at the front perimeter of the breech, behind the lip which retains the Freak insert.^[8]

Redux front sight removed from machined pocket.

Redux rear sight replaced with a LPI-brand adjustable sight designed to fit a Colt 1911 standard dovetail slot.

Power tube / Valve tube

The terms power tube and valve tube are used interchangeably to describe the same part. The Redux comes standard with a Lapco #4 power tube which has been bored to the same size as a Lapco #6 power tube and cut shorter so that it doesn't interfere with the Tune-Port-Compensator(TPC) portion of the bolt.^[9]

Barrel

The standard Redux barrel is screwed into the "snub" and is bored to accept Freak inserts. The Freak insert protrudes from the rear of the barrel by 1.25 inches and, measured from the rear of the insert to barrel tip, is 6.25 inches long.

Sights

The Redux slide is milled to accept standard 3/8" dovetail-mount rear sights like the 1911 Colt firearm it resembles. The front sight is a simple blade-style which is pressed into a machined pocket in the Redux slide and is removable for upgrading.

Tools

The Redux does not ship with a user manual but, being based on the Nelson design, is quite simple. Tools needed to service all external screws are:

• .050 allen wrench: rear sight blade grub screw & trigger back-stop grub screw
• 5/64 allen wrench: 4 extended grip screws, 2 feed port screws
• 3/32 allen wrench: 4 grip panel screws
• 1/8 allen wrench: 2 screws ahead of trigger, pump linkage arm screw
• 9/64 allen wrench: screw holding stock feed to feed port
• 5/32 allen wrench: long bolt holding valve body to gun

NOTE: this is an incomplete list; please consider adding to it if you have access to a Redux

Hardware & parts

All hardware is stainless steel.

General Assembly Bolts

• long bolt holding valve-body onto frame - 10-32 × 1 ¹⁄₄ socket cap bolt
• shorter screw ahead of trigger - 10-32 × 5/16 countersunk
• longer screw ahead of trigger - 10-32 × 3/8 countersunk
• valve to rail screw (underside of rail) - 10-32 × 3/8 countersunk
• field-strip lever screw - 10-32 × 1/4 round-head
• 4 extended grip screws - 6-32 × 3/4 countersunk MINUS ONE THREAD. (full 3/4 screws will rub against the inner body of the gun)
• feed tube screw - 8-32 × 5/8 cap head
• 2 feed block screws - 6-32 × 3/8 countersunk (1/2 is too long and will contact inner body, 5/16 won't bite all threads and may not be secure enough)

Trigger group

• rear trigger stop - 4-40 × 3/4 set screw (no head)
• front trigger stop - 4-40 × 1/4 cap head (4-40 × 1/2 cap head if a beveled sear or sear tripper is used)
• trigger return spring guide - 4-40 × 1 cap head
• trigger return spring - unknown (possible ball point pen spring)

O-Rings

Two o-ring sizes are used in the Redux, one to seal the bolt-head against the barrel/breech, the other to seal the valve seat.

• bolt-head seal, large o-ring provided in spare parts kit: #12 o-ring^[10]
• valve seat seal, small o-ring provided in spare parts kit: thickness 3/32, ID 1/2, OD 11/16 (standard, #12 o-ring)^[10]

Valve system

Springs

Hammer & valve spring set is a standard Nelson variety. Large springs are for the hammer, small for valve and stiffness/colour relationship is the same for both.

• Yellow - weak spring
• Green - medium-weak spring
• Blue - medium spring (stock valve spring)
• Red - strong spring (stock main spring)

In some sets, green/blue stiffness is reversed. ^[11][12][13]

Valve seal

The valve seal is made of stainless steel, similar to that of a standard CCI Phantom but with some changes. Instead of wrench flats on all sides, the Redux valve seal has only two wrench flats. These flats rest against a "lip" which prevents the wrench from contacting the face of the valve, in order to prevent tool marks. The wrench flats require an 11/16" open-ended wrench or an adjustable wrench set to that size.

NOTE: this is an incomplete list; please consider adding to it if you have access to a Redux

Operation

Full animation of the Redux loading and firing cycle.

Compressed gas enters the valve of the Redux via a port on the underside of the valve body, angled downward and to the rear, where a 12-gram CO2 cartridge protrudes from the grip-frame.

The cup seal assembly is pressed against the retainer with the aide of the valve spring.

This gas forces the valve to stay sealed and allows the gun to be cocked which prepares the hammer of the paintball marker for firing. Without the pressure of the gas in the valve the gun cannot be cocked.

As indicated by the term pump action the first step in firing the marker is the pump stroke. The link pin connects the pump handle and bolt.

The loading and firing sequence consists of several stages, assuming the marker is gassed up and has been appropriately tuned:

• the backward pump stroke - the bolt moves back, compressing the main spring until the bolt and hammer are connected by the sear. At this time a single ball drops into the breech
• the forward pump stroke - both the bolt and hammer move forward, chambering the paintball sealing the breech
• the trigger is pulled - the sear pivots and releases the hammer from the bolt. * the compressed main spring forces the hammer back until it reaches the rear of the power tube and provides enough energy to force the power tube back
• as the power tube is pushed back, the valve opens and compressed gas flows through the power tube and the tuned port compensator (TPC), projecting the paintball out of the barrel
• the valve spring compresses and the bolt losses its rearward momentum, followed by the valve spring pushing the power tube forward, along with the bolt, sealing the valve and stopping the flow of gas

References