Help Center

It can be frustrating to purchase upgrades only to find out that they don't fit your particular rifle. To make things easier we have compiled a database of information on compatibility of the various PolarStar HPA conversions into a wide range of models.

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What HPA system do I choose?

Gearbox Version - The first step in selecting an HPA conversion kit is to determine which gearbox "version" your AEG uses. Over the years, AEG manufacturers have created various gearbox versions suited to the shapes of different real firearms. In the case of our cylinder conversion kits such as the F2, the gearbox version will determine what switchboard model will be required to interface with the trigger and selector components. Since the Fusion Engine replaces the entire gearbox the "version" will determine which Fusion Engine model can fit into the replica.

Nozzle Type - It is important to know whether the nozzle of the AEG is centered in the cylinder (V2, V3, M249, etc..) or if it is offset vertically (M14, SVD). This will determine which HPA systems are compatible with your AEG. At this time, only the F2 supports AEGs with offset nozzles. Offset nozzles have a "O" prefix before the number.

 

Why do most of the nozzles have numbers instead of the rifle model?

For cylinder conversion systems we assign numbers to the nozzles instead of using the rifle model. This is because the nozzle length can vary between the same gun model when made by different manufacturers. This can be from the manufacturer designing the rifle differently, or from the thickness of the gearbox shell affecting how far from the hop-up chamber the cylinder sits. Therefore one nozzle length may work in different rifle models but not necessarily work in the same model from a different manufacture. For example, a standard MP5 could require any of 4 different nozzle lengths depending on the manufacturer.

For this reason we produce numerous different nozzle lengths to provide compatibility for a wide range of replicas. Although you might see our nozzles being listed with the gun model which the nozzle length is most commonly used with in the title, it is typically compatible with more that just that model.