Spring is fine. I am talking about putting 2,3,4,...10 mag ext on it and make a 100 round magazine :lol:
The extentions are actually designed a way that you can(and it does fit) stack one 10rd ext ont top of another. Like if you stack on 2 mag ext, you will have a 40rd mag. If you stack 3 mag ext on then you have a 50rd magazine. Only problem is the spring that comes with it is only long enough to make a 30rd mag.
Not sure how to post a picture but here is the link.
Three rnds two handed from 30ft. from the 5.7 = 2 in the 10 ring and 1 bull
My friends tried to beat it. Ruger 9mm has 3 in the 9 ring, the Sig 45cal has 1 in the 10 ring 1 in the 9 ring and 1 in the 7 ring.