This is a large-bore extension rectifier unit designed exclusively for the Maruzen CA870 air shotgun.
By adding a large-bore extension to the tip of a stock-size inner barrel, this custom part streamlines the compressed air that accelerates BB pellets, aiming to improve trajectory stability and grouping.
▍Important Before Purchase
This product cannot be installed on its own.
The following separately sold item is required:
KM Project Maruzen Air Shotgun M1100 Riot Shorty / CA870 / CQB Compatible Silencer Adapter with Reverse Threading [MZ8711R]
.
This product is designed to secure the internal large-bore extension barrel by screwing this product into the silencer adapter and then tightening the main body.
Cannot be used with custom guns equipped with long inner barrels.
This product is designed exclusively for stock-size inner barrels. It is intended to extend the stock barrel with a large-bore extension and add a streamlining (rectifier) effect.
▍Product Specifications
Item Content
Compatible Models Maruzen CA870 Air Shotgun
Inner Barrel Overall Length 80mm
Inner Barrel Inner Diameter 7.5mm
Inner Barrel Outer Diameter (Gun Side) 8.0mm
Inner Barrel Outer Diameter (Muzzle Side) 8.5mm
Holder Overall Length 55.2mm
Holder Outer Diameter 23.0mm → 20.9mm (Tapered)
Connection Thread M14×1 Reverse Thread (Male)
Mounting Thread M14×1 Reverse Thread (Female)
▍Product Development
Developed in Japan / Manufactured in Japan / Made in Japan
▍What is a Large-Bore Extension?
A large-bore extension is a **rectifier (streamlining)** system that smooths the flow of compressed air by allowing it to pass through a large-diameter barrel even after the BB pellet leaves the stock inner barrel.
Normally, when a BB pellet leaves the muzzle, the compressed air can burst out as turbulent air, slightly affecting the trajectory.
Thanks to the large-bore structure that ensures sufficient clearance to avoid contact with the BB pellet, this product streamlines only the excess air and suppresses unnecessary forces applied to the BB pellet.
▍Main Features
Designed exclusively for stock-size inner barrels
Streamlining (rectifier) effect provided by the large-bore structure
7.5mm inner diameter design prevents contact with BB pellets
M14 reverse threading for easy attachment and removal
Silencer shape provides a natural appearance
High-precision design developed and manufactured in Japan
▍Shooting Performance
This product is not a long barrel designed to increase muzzle velocity.
By adding a large-bore extension to a stock-size inner barrel and streamlining the compressed air that follows the BB pellet, it suppresses the generation of turbulent air.
As a result, it reduces unnecessary lateral forces applied to the BB pellet, and improved straight-line trajectory stability and grouping can be expected.
This is the ideal custom unit for users seeking more stable shooting performance while making the most of the stock barrel's performance.
![[KM Planning] Maruzen Airsoft Shotgun CA870 Large Bore Extension Rectifier Unit L80mm [RFLBY87R]](http://rock-et.jp/cdn/shop/files/RFLBY87R_5_1024x1024.jpg?v=1792387327)
![[KM Planning] Maruzen Airsoft Shotgun CA870 Large Bore Extension Rectifier Unit L80mm [RFLBY87R]](http://rock-et.jp/cdn/shop/files/RFLBY87R_4_1024x1024.jpg?v=1792387327)
![[KM Planning] Maruzen Airsoft Shotgun CA870 Large Bore Extension Rectifier Unit L80mm [RFLBY87R]](http://rock-et.jp/cdn/shop/files/RFLBY87R_3_1024x1024.jpg?v=1792387328)
![[KM Planning] Maruzen Airsoft Shotgun CA870 Large Bore Extension Rectifier Unit L80mm [RFLBY87R]](http://rock-et.jp/cdn/shop/files/RFLBY87R_1024x1024.jpg?v=1792387328)
![[KM Planning] Maruzen Airsoft Shotgun CA870 Large Bore Extension Rectifier Unit L80mm [RFLBY87R]](http://rock-et.jp/cdn/shop/files/RFLBY87R_1_1024x1024.jpg?v=1792387328)
![[KM Planning] Maruzen Airsoft Shotgun CA870 Large Bore Extension Rectifier Unit L80mm [RFLBY87R]](http://rock-et.jp/cdn/shop/files/RFLBY87R_5_medium.jpg?v=1792387327)
![[KM Planning] Maruzen Airsoft Shotgun CA870 Large Bore Extension Rectifier Unit L80mm [RFLBY87R]](http://rock-et.jp/cdn/shop/files/RFLBY87R_4_medium.jpg?v=1792387327)
![[KM Planning] Maruzen Airsoft Shotgun CA870 Large Bore Extension Rectifier Unit L80mm [RFLBY87R]](http://rock-et.jp/cdn/shop/files/RFLBY87R_3_medium.jpg?v=1792387328)
![[KM Planning] Maruzen Airsoft Shotgun CA870 Large Bore Extension Rectifier Unit L80mm [RFLBY87R]](http://rock-et.jp/cdn/shop/files/RFLBY87R_medium.jpg?v=1792387328)
![[KM Planning] Maruzen Airsoft Shotgun CA870 Large Bore Extension Rectifier Unit L80mm [RFLBY87R]](http://rock-et.jp/cdn/shop/files/RFLBY87R_1_medium.jpg?v=1792387328)
