If you are looking for a replacement roller bearing for your WE-Tech M4A1 rifle, you might have come across the WE-Tech M4A1 Guide Roller Bearing. However, before you make a purchase, there are some things you need to know about this product.
Firstly, while the manufacturer claims that this roller bearing can increase recoil and the rate of fire, the truth is that it does nothing. There is no noticeable improvement in the rifle's performance after installing this roller bearing.
Secondly, the shape of the cartridge bearing is not compatible with the charging handle. The shoulders or outer edges of the bearing are square, while the channel the bearing rides in (the charging handle) is round. As a result, the bearing never rolls smoothly, and you can feel it wobbling and wandering from edge to edge when charging the handle.
Thirdly, the WE-Tech M4A1 Guide Roller Bearing comes with a brass insert that reduces the inner diameter of the generic bearing to match the thin metal axle in the WE rifle. However, the brass insert wears out quickly, and you will notice the bearing becoming wobbly and sloppy in a matter of weeks.
Finally, one of the main reasons for switching to a cartridge bearing is to avoid using a brass part that wears out quickly. However, this particular roller bearing has a brass insert, which defeats the purpose of switching to a cartridge bearing in the first place.
In summary, the WE-Tech M4A1 Guide Roller Bearing is not recommended for use in your WE-Tech M4A1 rifle. It does not improve the rifle's performance, and the shape and brass insert cause more problems than they solve. Instead, stick with the stock roller bearing or look for a different brand that produces thin roller bearings that are better suited for your rifle.