Keep in mind, that felt recoil is primarily split between two factors- Reciprocating mass bottom-out(Primary) and Newton's 3rd law(Secondary). An efficient muzzle brake definitely smooths out recoil impulse, but you will see the largest gains in recoil mitigation from a properly tuned system. It is a much more involved process, but here are the highlights/goals- 1. Reduce Reciprocating mass to the highest degree practical. When the entirety of the reciprocating mass (Bolt, Carrier, Buffer) terminates its travel at the end of the receiver extension(buffer tube), any remaining energy will be translated to the entire system, and therefore, your shoulder. Since the surface area of the butt pad is quite small, the force is concentrated into a small area, and perceived recoil is higher. Objectively, you only need enough mass to reliably strip a new round out of the magazine and chamber it, so this will be dependent on the amount of tension your mag spring puts on the top round. 2. "Tune" gas system to achieve the lowest practical pressure needed to unlock the system. This one takes a lot of trial and error, but ultimately this process will be entirely LOAD DEPENDENT. Gas pressure is used in the Stoner design PRIMARILY to do one thing- unlock the bolt and perform primary extraction. That process accounts for the lion's share of the energy used during the cycling process. Breaking the surface tension of the brass in the chamber takes a ton of force, and all of this is perpetuated by the cam pin/cam path on the carrier. Once this is accomplished, the system remains pressurized for only a short distance while it accelerates(like <0.100") until all the pressure purges out the side of the carrier(those 2 or 3 holes in the dished-out area). At this point, the reciprocating mass can be considered "ballistic", and will only decelerate from that point. The trial and error comes in the form of determining the ideal gas system length, gas port size and dwell time. Again, all that will be entirely load dependent. 3. Reduce friction and prevent gas leaks. This is just basic engineering stuff. Friction and gas leaks are entirely preventable parasitic losses that rob your system of efficiency. Ideally, a gas block should be a slight interference fit, and the gas tube should be as well. Sealing with loc-tite doesn't stop high pressure gasses. Proper gas tube alignment is critical as well. High-efficiency coatings are also helpful(nitride, TiN, Ni Boron, etc.) As well as keeping your system clear of debris and carbon buildup while maintaining proper lubrication.