- Rotary HOP-up unit
- Includes silicone HOP-up bucking & nub
- Compatible with most M4/AR-15 & AR-9 AEGs
If you want a budget-friendly HOP-up upgrade without sacrificing performance, the S&T Armament Rotary HOP-Up Unit for M4/AR-15 AEGs is a smart choice. Highly regarded by Airsoft techs, this polymer rotary HOP-up chamber from S&T Armament offers excellent compatibility and consistently tight tolerances, delivering impressive results across a wide range of bucking and nub setups.
Supplied as a near drop-in solution, the set includes everything required to build the HOP-up unit aside from the inner barrel. It comes paired with a silicone HOP-up bucking and a standard cylindrical nub, making it well-suited to medium-power builds around 350 FPS. For players focused on reliable, cost-effective performance upgrades, the S&T Armament Rotary HOP-Up Unit for M4/AR-15 AEGs is an easy addition to any upgrade kit.
Fast Delivery
Delivery & Postage
Here at Patrol Base, we send all our packages from our Warehouse based in the UK with the exception of European Warehouse Items. All of our parcels are sent with specially picked couriers to ensure your parcels get to you on time and in one piece.
For more information please check out our Delivery Information Page.
Estimates
Below are some rough postage prices for orders. Please note these are subject to change and are only a rough guide. For a more accurate postage estimate please use the Postage Calculator at the basket.
UK 3-5 day Standard
£6.95
From
Dispatched with 24hr UK mainland
£8.95
From
Highlands / Islands
£24.99*
From
* Please note that Scottish Highlands, and Islands postage prices can vary wildly. Please refer to the Postage Calculator at the basket for the lowest possible price.
Returns
We want you to be absolutely happy with our products and services, so we provide the simple Patrol Base guarantee: if on receiving your item you are unhappy with your item for any reason then simply send it back to us. We will replace or refund the item.
You can return any item for any reason whatsoever, even if you have just changed your mind, within 14 days of receipt of the order. This is in addition to your rights under the Consumer Protection (Distance Selling) Regulations 2000.
For more information on returning products, and how to do it please visit our Returns Policy Page.
Description
Features
- Rotary HOP-up unit - Considerable improvement over gear HOP-up units:
- Easier to adjust in fine increments
- Holds its setting more effectively over time
- More pressure is applied for use with Heavy BBs
- Includes silicone HOP-up bucking & nub - All parts to assemble included
- Compatible with standard AEG HOP-up buckings & nubs - Plenty of options!
- Compatible with most M4/AR-15 & AR-9 AEGs - Some non-standard designs may require modification
Package Includes
- S&T Armament Rotary HOP-Up Unit for M4/AR-15 AEGs
Specification
General
Parts & Accessories Type | Electric Internal Parts, Internal Parts, |
|---|---|
Internal Part Type | Hop-Up Unit |
 | Custom Parts |
Construction
 | Black |
|---|---|
 | High density polymer HOP-up unit. Silicone HOP-up bucking. Rubber HOP-up nub. |
Internal Part Construction | Polymer |
Part Specific
Part for Power Source Type | Electric |
|---|---|
 |
|
Package Includes |
|
Electric Part Specific
Gearbox Version Compatibility Variant | Version 2 |
|---|
Size guide
Parts Fitting
Upgrades and Downgrades should only be undertaken by experienced players, or Airsoft Technicians. Please note, changing any internal parts of a weapon voids its warranty unless done in-house by our staff.
Please ensure that when fitting parts the part purchased is the correct part, as once a part has been fitted we cannot accept return.
We do know that players love to tinker, so we're here to give you help should you require it, and if needed you can get in touch with our workshop for more help!
Unique Parts
Please note that some parts may be unique to a specific brand of weapon. For example: Parts for an ASG M4A1 may not fit an ICS M4A1.
Parts from the same brand typically have a high chance of fitting, though be warned, some replicas use unique parts, so please ensure the part will fit before you attempt to fit it.
If you require help with fitting any parts feel free to get in touch with us via our Contact Us Page.
For more information with fitting parts, or should you require help, feel free to get in touch with our Workshop Department via our Contact Us Page.
Terms and Conditions relating to parts fitting can be read on our Terms and Conditions Page.