The most effective way to eliminate recoil via equipment on an AR is with a good compensator. I've tried everything from different gas systems to heavier buffers, etc. Don't get me wrong, all of those things will make a difference; they just won't make a dramatic difference except for the comp.
The single biggest difference is a good compensator. The downside is that most good compensators are obnoxiously loud for other shooters and usually noticeably louder for the shooter in question.
The one exception to this, also happens to be the best compensator - a sound suppressor. Unfortunately, those have regulatory issues of their own and hanging 20oz of weight off the muzzle often creates more stance/balance issues than the suppressor solves by recoil reduction.
One other option to keep in mind is formal training, a good 3-day training course can teach you a proper stance that will let you minimize recoil using your body and get you back on target for quick follow-ups even with much stronger recoil than a 5.56mm AR - and that skill is transferable to other rifles as well and a lot more useful than a new piece of gear.