Cutting a 7.62x39 ar barrel

[greene]

I have an upper I built with a faxon 16 inch mid gas 7.62x39 barrel. It's been 100% reliable from the 1,500 rounds I put through it, suppressed & unsuppressed. I would like to cut it down to 13.9 & pin/weld. My question is with the 7.62x39 round is cutting the barrel going to give me the same results as cutting a .556 barrel? Meaning softer recoil impulse & less gas in the face while suppressed & maintain reliability. Don't want to risk making it unreliable while the cans not on, but do want it as short as possible & the 13.9 - 14.5 .556 uppers I have are my favorite blasters. Thanks