AR15 upgrades without the hassles
There are enormous numbers of things you can do to customize your AR15 style rifles but one thing to consider is every time you do a gunsmithing job to your firearm, that’s one more thing that may not be installed correctly. The more you add on, the more can fall off, that goes from changing magazine releases, trigger guards, triggers, hand guards, gun grips and and more. Instead of taking everything off of your firearm, it’s really better to just get another upper receiver or another firearm. Especially if you think there is a chance you won’t like the modifications. Piston conversions are another thing to be careful about because the gun should be functioning reliable after the changes and not less reliable. And remember don’t fix something that isn’t broken.
Going back and forth from a direct impingement firearm to a pistol driven gun and then back to DI is a bad idea. There are some really cost effective versions of the piston uppers like the CMMG uppers for sale at Rogue Elite. LWRC is still the king of the piston driver uppers especially after the new lightweight upper receivers have come out that are just slightly over $1000. The M4 LEPII is a popular upper receiver and only change of your recoil spring should do the trick. The key to maintaining a reliable firearm is to maintain it, not constantly mess around with it. If you want to do minor changes, go ahead, major changes to a firearm, get a new one. The cost in time and money may be about the same.
There is much to debate when it comes to discussing the effectiveness of the 5.56 round. When it was originally deployed in the M16A1, the military had issues with the reliability of the gun, but I have heard not one complaint from any Vietnam vet about the lethality of the round. That was when the military was using a 20inch barrel with a 55gr bullet travelling well over 3000fps. The bullet is extremely violent at that velocity. The lethality of the round was greatly diminished when the military started using shorter length barrels and the 62gr SCBT also known as SS109 or M855. Although it is only 6grs heavier, the bullet is so well balanced that it basically zips straight through a target and the terminal ballistics are not very good below 2800fps which is practically what an M4 shoots it at near the muzzle.