AEG making a slight whirring sound after shots

[GilbertTheGoose]

I took apart my gun the other day to change out the spring and now that it's back together it makes a weird whirring sound after most shots, it kind of sounds like the motor is turning but I honestly have no idea. The gun works totally fine and seems to perform very well (I don't have a chrono so I don't know what it's shooting at but I installed an m90 spring so in theory should be like 300-328). Should I be worried about this sound?

Here's a video of it:

https://www.youtube.com/watch?v=yOuze0J-NoE

 

[Lozart]

Sounds like you forgot the Anti Reversal Latch when you put it back together...

 

[GilbertTheGoose]

I definitely put it in but I guess I just put it in wrong  

thanks

 

[Rogerborg]

They can be right little sods.  A strong magnet placed underneath the shell helps to hold everything in place.  I was a bit sceptical before I tried it, but it does seem to work.

 

[Lozart]

I definitely put it in but I guess I just put it in wrong  

thanks

Click to shrink...

You might have it back to front then....