You mean the A5 parts are oos or just the spring? You can use any rifle length spring with it.
I'll have to take a much closer look at that. You have to have the special Vltor tube for that as well... right?
Yes - the Vltor A-5 is designed to run their buffer and spring in their tube. You can change the stocks for any mil-spec diameter stock, but the buffer, recoil spring, and tube should be Vltor.
Blue may know something different on that, I've just seen a few guys locally have cycling issues swapping parts in the Vltors.
I would not recommend the Noveske switch block for what you are doing. The Switchblock uses three settings: no gas, suppressed, and unsuppressed "open". If you need to tune your gas system to operate, you don't have the same ability to adjust the flow as you do with the other gas block options you are looking at. The Switchblock is a good system, but not optimal for your build, JMHO.
