I usually run into issues on the other end, it seems that most rifles tend to be overgassed...but my first inclination wouldn't be to make non-reversible mods to set a rifle up to work with the cheapest, crappiest, out-of-spec, low pressure ammo I could find.
If you were to just clean up the port and make sure the rest of the gas system is clear, after that there are different buffers to play with, it seems like that would do it.
I usually end up with a heavier buffer, but then I've never fired a round of Commie steel cased 223 ammo, but I wouldn't expect much from it if I had..
I think shortening a +2" gas system from 26" to 20" already counts as a "non-reversible mod". LOL.
This problem has nothing to do with typical commercial grade 5.56 barrels being overgassed, which is true but a completely different thing. If you shortened a typical overgassed 16" carbine barrel to 10", you'll find it undergassed some of the time too. (Although I did shorten one 16" DPMS barrel to 10.5" that still had plenty of gas after shortening; that was a good illustration how overgassed it was originally.)
