[ILLusion]

You'll need to clip some coils off the spring.

Also, good luck having enough gas to lock the slide back after emptying the mag... that spring is insanely heavy unless you clip off a good number of coils.

OR... upgrade to a Nova steel spring plug. The problem is with the inner diameter of the Marui spring plug... it tapers off as it goes in, and the spring ends up not being able to go all the way to the bottom.