For my next build I was looking at dissipater uppers and wanted to know if there was an advantage to using one with a mid-length gas system (as opposed to using the standard rifle gas system)?    If I intend to use a suppressor on this upper couldn't I just get away with using the longer rifle system?  Thanks.

-Will

Yes, you should be able to get away with a rifle length gas using a suppressor on a 16" barrel as the suppressor will bump your gas pressure.

Nick

The dissipater gas system is not a rifle length system.  If you look at one with the handguards removed, you will see that it is a carbine length gas system with a dummy gas block for the front sight.  I went with a mid-length gas systems on my rifles b/c the gas port, gas key, and bolt with see a lower pressure and will have less wear and tear.  Also, the recoil is not as sharp.  I haven't had any problems with the mid-legth systems but I have had a few with my carbine length systems.

If it matters, with a midlength FSB you can use the bayonet with the 16" barrel. With the carbine length system you would need the 14.5" barrel to make the bayonet work.