The Vltor upper rec has M4 cuts so you will have to use a barrell with M4 cuts. Almost everyone with M4 cuts has 1/7 barrel. So I need to run what grain of bullet? or does it matter?
Posted: 7/14/2009 7:27:31 PM EDT
[#1]
Doesn't really matter. 1:7 barrels are designed to accomodate heavier rounds, but plenty have fired 50-55gr rounds without problems.
If there truely is a difference in performace between light and heavy rounds in a 1:7 barrel, its minimal.
