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The EK Archery Cobra R-Series is one of the most expandable crossbow systems in our range. A Cobra R9 or RX can be modified and upgraded, the Adder can be fitted with a different magazine, and several functional upgrades are also available for the Cobra Siege.
On this page you will find the main upgrade paths using original EK Archery components and selected UPBOLT upgrades. This makes it easier to determine which parts you need and which configuration best suits what you want to achieve with your Cobra.
One of the interesting features of the Cobra R-Series platform is that a suitable R9/RX 130 lbs configuration can be upgraded to an Adder configuration. The original EK Archery B30097A Adder Grip Set provides the basis for this conversion.
This set consists of the Adder grip and corresponding replacement trigger assembly. Together, these provide the technical basis required to install a suitable Adder magazine.
Use the Adder Grip Set with Trigger Box as the basis for the 130 lbs R9/RX to Adder conversion.
You can then choose between two different magazine options:
If you already own a Cobra Adder, the UPBOLT MAG-V2-AD is particularly interesting as a premium magazine upgrade. The magazine holds 8 bolts and is designed for use with both 7.5" and 15" R-Series bolts.
This means the upgrade offers more than simply one additional shot. The ability to use different R-Series bolt lengths and the additional mounting options make it particularly useful if you want to further configure and expand your Adder.
If you primarily want an original and complete 7-shot solution, the EK Archery Adder 2.0 magazine is the logical option. If you want 8 shots, support for both short and long R-Series bolts and more mounting options, the UPBOLT MAG-V2-AD offers additional functionality.
The EK Archery Cobra Siege can also be further expanded with UPBOLT components. The MAG-V2-SG is an 8-shot magazine developed specifically for the Siege and supports both short and long R-Series bolts.
Combined with the Siege's integrated underlever cocking system, the magazine creates a very different configuration from the standard single-shot setup.
The UPBOLT SG-BIPOD provides the Cobra Siege with a suitable mounting point for a bipod. The adapter has been developed specifically for the Siege, providing a neat and functional upgrade without requiring permanent modification of the crossbow.
The bipod adapter can be used as a standalone upgrade, but it also makes a logical combination with the MAG-V2-SG magazine when further expanding a Siege setup.
In addition to the magazine and conversion solutions, UPBOLT offers smaller accessories for making practical adjustments to a Cobra R-Series configuration.
UPBOLT does not replace the EK Archery platform. Its products are designed as additional upgrades for existing Cobra systems. This is why our range combines original EK Archery components with selected UPBOLT upgrades where they provide additional functionality.
For an R9/RX conversion, for example, you can use the original EK Archery B30097A and then choose between an original EK magazine or a more extensively configurable UPBOLT magazine.
The fact that a magazine can accommodate a particular bolt length does not automatically mean that every bolt of that length is suitable for every draw weight or Cobra configuration. Always check the correct bolt type and bolt weight for the crossbow and power configuration being used.
Before upgrading, first check which Cobra model, draw weight and configuration you are using. The individual product pages specify the exact compatibility and the components required for each upgrade.
Order before 19:30 = shipped the same business day
95% available directly from stock
Rated 9.2/10 from 3,600+ reviews
Specialist in bows and crossbows