I currently run an all stock Daniel Defense DDM4V5. I was wondering how I could reduce the recoil of the rifle without compromising reliability. It currently has the stock A2 flash hider and I only shoot Lake City XM855 ammunition, 62 grain. It utilizes its stock factory buffer spring with its stock H buffer. I will be acquiring a muzzle brake for it. I've been doing some research regarding how different buffers and their springs could reduce felt recoil. The con I found though, is that it may possibly hinder the reliability of the weapon if the balance is not correct. Should I bother modifying the buffer/spring or should I just keep it stock.

Put an SJC Titan brake on it. Works wonders.

Yeah from what I've seen/heard, the performance of that brake is excellent! It's a little too long for my application though. I was gonna go with the precision armament M4-72 Severe duty instead.

Jpg brake is best per testing I saw

Since you only plan to shoot one type of ammo, an adjustable gas block should work great

Second this.

Its mid-length gas? If so, I like running an H buffer with a Sprinco blue spring when running standard carbine length receiver extensions. A great combination in most cases, in my experience.

Even better than that is the Vltor A5. It requires proprietary buffers and a rifle spring, but is an excellent upgrade from the standard carbine recoil system. This, along with a good brake, will soften your gun up even more.