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Development lab: Unilock Feednecks

This page contains information on the design for our Unilock feedneck system. While a feedneck may seem simple at first glance, it's actually one of the most complex parts of a paintball marker due to their small size and high complexity of cuts throughout the fabrication process. The level of design and revision time spent on Nummech's clamping feedneck is simply staggering; it took years to refine, and its design actually pre-dates any of Nummech's other products (although the Unilock was not made available for public sale until 2014). This is one of our best upgrades due to its clear-cut advantages over stock feednecks.

Unilock feedneck design:
Historically I've always been a fan of feednecks that use a locking collar, as compared to feednecks that consist of one-piece flex housings. The locking collar system allows the feedneck body to have a greater clamping range because each little slotted section need only flex by a small amount when tightening around a hopper. The "newer" one-piece design is favored within the paintball industry because they're more simple and easier to produce (therefore cheaper) but one-piece clamping feednecks seem to experience less effective clamping range. Their clamp motion is spread across two big areas, so a certain amount of care must be taken to avoid long term damage. I see online posts about this issue somewhat frequently; the one-piece design appears to work adequately but the "older" locking collar feednecks are clearly a tried-and-true system which doesn't encounter the same issue.

Above: Visual comparison of clamping feedneck designs, both lock collar and one-piece styles.

Enter the Nummech "Unilock" feedneck! The reason we chose the name "unilock" was twofold; we built the feedneck to be compatible with any Empire or Eclipse feedneck boss mounting points, and additionally because the locking collar design has a huge clamping range which is compatible with virtually all types of loaders.

Above: Modern Unilock feedneck CAD design (internal knurling not shown).

Unilock prototype: (2010) The original Unilock feedneck design was very minimalist compared to the production version that we make today. It was borrowed from a special marker project in 2011 which used an earlier feedneck that I designed back in 2009 when performing contractual design work. I updated the original plans to be compatible with Empire's feedneck boss dimensions, meant to be paired with a boss-style mounting point on top of the marker body. All our Nummech bodies have this mount built directly into the milling; players with other markers can also use any of our Empire-spec threaded adapters too. The choice to use Empire's feedneck spec was due to its shorter height and universal compatibility. Any quality Empire feedneck is also compatible with Eclipse's boss, while the reverse usually is not true.

Above: Prototype Unilock feedneck components.

The first Unilock feednecks were made in this "minimalist" shape seen above. The design was sound, but it's a good example of a "first run" product which needed some refinement before making new ones. I made lots of changes, including some of these:
- Modified the cam-action in such a way that it would lock in the "tightened" position, instead of popping open under force.
- Enlarged the lever and lockring to make them easier to operate, which also had the benefit of adding strength to both parts. The lockring underwent a total redesign; I altered its shape such that the top surface would "wrap" around the inside of the feedneck housing itself, which prevents damage to the housing's clamping ridges when inserting a hopper.
- The threaded roll nut cannot be the same material as the aluminum lever (because they will seize together) so I chose brass for the prototype because it's easy to machine. However, I wanted to upgrade the material to stainless steel because it's drastically stronger and won't tarnish over time, unlike brass which tends to appear green after a while. I also like the silver appearance of the stainless steel nut, although that's a minor benefit.
- Widened the gap in the middle of the body clamp area, which allows an object to be inserted for easy installation and removal.
- Added additional details and cuts around the outside to make the feedneck appear more than just a tube shape.

Production Unilock: (2013) After nearly two years of testing, we finally set out to make the first batch of feednecks in late 2013, which were then released around 2014. Nummech's new Shocker and Axe bodies had become available, so offering a feedneck bundle became important. Without a Nummech option, the only choice was to buy one of the prototypes, or end up buying Empire's inferior one-piece feedneck which was the only other compatible design at the time.

Above: Revised production-style feedneck housing at various stages of manufacturing.

Naturally many other players requested buying the feedneck once it became available, even when they were using a different marker. To fulfill demand, we quickly made a second batch and expanded the color choices to both dust and gloss, silver or black. Below is a picture of the finished feedneck on an SP Nerve marker.

Interested in machining? Check out this video which shows the feedneck milling process on one of our CNC 4-axis mills:

Above: Production milling for the feedneck housing component.

Each feedneck comes ready-to-be-installed with a plastic shim tool, which ships attached to the feedneck housing. The small shim allows you to safely open the feedneck's clamp just enough to precisely slide it onto the marker's mount. Afterward the shim is removed and the clamp can be tightened like normal, and the shim can be kept in your toolbox for future use. The quick-and-dirty way to do this is with a screwdriver or metal coin, but I love using a little piece of plastic since it pretty much eliminates scratching of nearby parts (marker body). We cut the plastic shims out of a large cast sheet stock on our laser router.

Above: Plastic installation shims.

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Above: Cutting a sheet of plastic shims on a laser router

The paintball market determined a pricetag for this product before it was ever released ($40 each). By its production time, I would like to sell the Unilock for more like $55 each, but it's difficult to convince people to spend that much money on a feedneck because the amount of time involved is difficult to understand. Unfortunately for us, the Unilock feedneck requires a lot of time to fabricate, compared to items of similar cost such as a trigger or drop forward, which can be produced in nearly half the time yet carry the same pricetag. It becomes obvious why most companies have eliminated the complex feedneck designs like the Unilock; the less complicated designs make it easier to justify the typical $40 pricetag that follows most feednecks. However, despite its high complexity, we refuse to simplify the design because it's the best no-compromise system available. It's the only way to get it out into players hands where it belongs!

Thumbscrews, knurling, and No-rise height: (2014) Players reported great results using the Unilock in action after the first big batch in 2014. The lockring design fixed clamping issues with several OEM feednecks on markers like Mini-GS, which was indeed the intended benefit. However, we received two main requests for revisions. The first feature people wanted involves a tool-free clamping adjustment knob rather than using an allen key for adjustment. This was an easy feature to add just by fabricating a new thumbscrew which could slide right in the area normally occupied by a cap screw. Technically the new knob component added yet more time to the production cost, but the knob was such a good idea that we decided to start using it with all feednecks going forward with no added cost.

Above: Raw thumbscrew knobs ready for anodizing.

The second feature people requested was a shorter profile to accommodate "hacksaw mod" hoppers. The existing Unilock is already shorter in height compared to many stock/OEM parts, but some players were still looking for something even shorter. Solving this issue would require some creative work; my biggest problem was that our high-range clamping ability is based on the housing's height, so reducing height would probably restrict the clamping range too. The other problem is that a shorter feedneck requires a modification to the hopper, usually done with a hacksaw. Homebrew hopper modifications aren't difficult, but they do require additional work on part of the player, which complicates things for us trying to make "drop in" upgrades that don't require modifications at home.

Well, people still wanted the option for a shorter feedneck. I came up with a redesigned feedneck housing measuring slightly shorter while still maintaining compatibility with Nummech's existing lockring, lever, and thumbscrew. I called it the "No-rise" version just like the super short feednecks of yore. The stubby height is even shorter when used on an Eclipse marker.

Above: Unilock No-Rise CAD design and comparisons.

The Unilock No-Rise is very similar to the standard version, but uses a smaller clamping screw and has more intricate cuts around the outside area, because less space is available for milling. The no-rise was prototyped and sent out for testing; results were still good, but the clamping range was definitely reduced. For this reason we decided to continue selling the original Unilock feedneck in addition to the newly-shortened variation. If people ask which type is best, I always recommend the tried-and-true standard height Unilock because only a small subset of players are die-hard enough to hacksaw their hoppers. Most people just need reliability and clamping range, which is where the standard Unilock is best.

Above: Unilock No-Rise installed on various markers.

The final "functional" upgrade to the feedneck design was done shortly after introducing the no-rise height. Feedback from some of the players involved with testing the feedneck indicated that there was one thing still missing: internal knurling texture that could grip the hopper with greater force. The reasoning was sound because the no-rise has less clamping height, so why not allow it to grab tighter? Well there was indeed reasoning behind the smooth surface, because it's MUCH cheaper to manufacture. The knurling adds a lot of upfront cost while also complicating the quality control process. However, the knurling remained the one single last feature we've yet to see on these feednecks, so quickly the decision was made that it was worthwhile.

Above: Feedneck blank inside the CNC, with finished internal knurling.

The feednecks underwent even more testing since the knurling needed a tighter-tolerance specification. In testing I learned the knurling pattern need only extend a shallow distance down inside the feedneck's inner clamping area to be effective. The deeper the knurling....the more expensive it was to repair the tool when it wears out. So a good compromise was struck between providing enough knurl grip to easily grab the hopper, compared to keeping the manufacturing cost reasonable. Again there's higher cost for this, but the feedneck's MSRP has already been set and cannot be increased despite the higher production cost. Certain features are worthwhile to be given for free if it makes the finished product that much better.

Above: Example feednecks with grip texture.

Once the knurling was tested and refined, we began using it in late 2018 however it wouldn't end up on the shelf for a while. We beefed up the no-rise feednecks (they became "version 3" which is engraved on the bottom) then added knurling to both the standard and no-rise heights.

At this point, the Unilock has been pushed to the point where I don't believe there's much remaining from a functional standpoint. Over the years we've refined the design so much, and added so many new parts and features while still cramming everything into the same small assembly.... all while maintaining the same MSRP price to ensure the product is accessible to everybody. It's truly one of the most successful Nummech upgrades thanks to all the feedback and suggestions from players everywhere.

Expanded mounting options: (Bob Long, T-rex, PAL, others?) After making several new batches of feednecks, demand was increasing for more choices to be added. Empire's mounting dimensions were becomming popular among other paintball machinists, but the remaining issue was that some other companies use (or used in the past) non-compatible mounting shapes which were not compatible with either Empire or Eclipse. The most-requested example includes Bob Long "no groove" mount found on the commonly-called "gen-6" marker bodies, which included the G6R, Insight, Onslaught, MVP, and some Marq's (pre-FieldOne). There was never any aftermarket solution for any of those markers, so it makes sense for us to support them since people were directly asking for an alternative to the stock feednecks.

And thus the "Bob Long no-groove" Unilock was created! It was originally called the BLAST unilock (engraved on the bottom) but we later changed the name to "Gen-6" since it's a little more descriptive. The Gen-6 mounts were only compatible with a certain type of Bob Long marker which were made between around 2011 through 2018. Older markers use different feednecks whereas newer Field-One markers such as the Force use a different-shape mount.

Above: Standard-height Bob Long Gen-6 Unilocks

Later (out of chronological order with the rest of this article) we also added compatibility for the HK T-rex VCOM marker. While those were made during the era of Field-One's new Force feedneck mount, for some reason the HK T-rex uses a different mounting size that is shared with no other marker. No problem, we'll make parts for it too!

Above: HK T-rex Unilocks

Later still, a new Unilock mounting option was added for the Eclipse PAL feedneck mount (for both the standard-height and no-rise versions). The two current PAL-compatible markers are limited to the Emek and MG100 at the time of this writing, and they are unfortunately incompatible with the previous Eclipse feedneck mount. To address this, yet another deviation was necessary to allow compatibility:

Above: Standard-height PAL Unilocks

Interestingly, this new PAL mount marks the first major redesign on the external shape of the feedneck. All versions of the Unilock used identical cosmetics prior to the PAL mount, which required a noticeable redesign to make room at the front for the overly-large mounting feature located on the marker body.

Anyway, the PAL Unilock can be mounted onto a PAL marker but the feedneck itself effectively disables the PAL function. It's intended for use with an electronic hopper instead of a PAL hopper; the reasoning is that there's only one single PAL hopper (made by Eclipse) so it doesn't really have the need for an aftermarket feedneck for regular use, since the stock feedneck grabs it just fine. However, the stock feedneck doesn't work too well when paired with smaller hoppers like Virtue Spires, and it's also made from plastic so it doesn't share any of the features found on our machined aluminum feednecks.

Regardless, if there's demand in the future, I would be pleased to make a PAL-compatible feedneck too. However I don't believe many people would buy it compared to using the factory feedneck.

Finished Builds: (assorted markers)

Written by Andy "Ydna" DuBuc
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