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Doc’s Automag Barrel Adapter
By Bill Mills - October 2003
In the mid 1990s upper level tournament paintballers usually shot one of two paintguns – the Autococker or the Automag. Aside from functioning in completely different ways, the two paintguns also utilized entirely different barrel mounting systems.
While the Autococker used a threaded, screw in barrel, the Automag was equipped with a twist lock system that allowed the barrel to be removed much faster. Additionally, the breech of an Automag is built into the barrel, meaning that pulling out the barrel provides complete access for cleaning in case of a ball break.
That being said, there are also some drawbacks to the Automag’s twist lock system. The barrels are more expensive to manufacture, heavier (due to more metal needed around the breech) and less common than Autococker barrels, since many other paintguns have adopted the Autococker threading as a standard. Recent models of the Automag have been produced by Airgun Designs which utilize Autococker style barrel mounting, and it is foreseeable that AGD may eventually drop the twist lock altogether.
From AGD’s perspective there is an entirely different reason to change lock systems. With the twist lock barrels, the inner diameter of the breech of an aftermarket barrel is out of their control. Bodies which have the breech as part of the receiver (like AGD’s X-Mag and ULE bodies) all have the same breech diameter, so the specifications for bolt diameter and fit can minimize blowback and maximize gas efficiency.
Over the years a number of people have proposed Automag thread adapters, to convert an Autococker barrel to twist lock into an Automag. Some airsmiths said it wouldn’t work because the barrel would unscrew from the adapter during the twist lock process.
Then Barrett “Doc” Nickel took up the challenge. Doc is a machinist and airsmith in Kenai, Alaska. In the late 90s, Doc built a reputation as a genuinely helpful guy in WARPIG’s Tech Talk forums, and because of his knowledge and willingness to help, soon developed a customer following as well. Presently, Doc does business under the name “Doc’s Machine” and has gained new notoriety as the author and illustrator of The Whiteboard weekly web comic, and host of the Tinker’s Guild forum on his web site.
Rather than adapting the barrel to the paintgun, Doc’s device adapts the paintgun to the barrel. The adapter is a steel sleeve about three inches in length. The front is threaded to accept a barrel. In the rear is a breech opening, and near the middle is the ball detent slot. Auomag barrels feature a wire or plastic nubbin bound to the barrel with o-rings for their ball detent, in order to prevent double feeding of paintballs.
The adapter, which is really a breech meant to fit inside the Automag utilizes a single rubber like nubbin. Should this nubbin wear out, it is easily replaced. It is a standard Spyder nubbin that has been modified by having it’s end cut off. Spyder nubbins are available through most paintball shops at a cost under $2. Replacements don’t even need to be cut, they will wear to the proper length.
Instead of twist lock channels the adapter has a series of three holes. In the grip rail of an Automag, Automag RT or E-Mag is a spring loaded pin that engages the locking slot on a barrel. This pin will also engage the locking hole in the adapter, and prevent the adapter from twisting or sliding in our out of the ‘Mag body. The three holes allow the adapter to be used with right, left, or center feed bodies. The adapter works with all Automag bodies that utilize the Automag twist lock barrel system.
Installation of the adapter into an Automag RT for testing went very quickly. The entire process which included removing and reinstalling the sight rail (which is held on by 6 screws) took less than 5 minutes.
With the sight rail off, and the body removed from the RT, it was time to install the adapter. The unit ships with a piece of clear tape holding the nubbin in place to prevent loss. The instructions recommend using Dow 33 Shocker Lube to keep the nubbin from binding on the ‘Mag body. WDP’s Love Juice grease seemed to do the job just as well.
A tip not found in the instruction manual was to install the adapter by screwing it onto a barrel. This allowed the barrel to act as a handle, making it easy to slide and rotate the adapter into place through the long front end of the RT body, and would be similarly handy with a Minimag body.
With the breech opening lined up with the power feed, and lock hole lined up with the spring pin from the rail, the RT went back together with the front grip screw and rear banjo bolt locking the body to the grip frame. The installation was done.
Powering the RT with an AGD Flatline air system, it performed well with barrels from Smart Parts, DYE Precision and J&J Performance. None showed any ill effects from the adapter’s use. The RT used for testing had an Airgun Designs Level 10 bolt kit installed. While it was not a problem during testing for review, the vibration of a stock Automag bolt might cause a barrel to unscrew from the adapter during use. It was found that a thin o-ring around the neck of the barrel helped to lock it in place, and should alleviate any fears of the barrel backing out.
After an easy install and reliable performance, the real question this adapter brings to mind is, “why didn’t anyone do this earlier?”