So here's the deal; I've had a Colt M4 with a Rock River upper for a few years now and I love it. Runs great, has seriously never jammed, my only issue has been the front sight. It was tilted about 5 MOA to the left out of the factory, so it took me a while just to zero in cause I couldn't figure out why I was totally blanking at 100 yards. Even once I got it zeroed I quickly switched to a red dot cause frankly the steel sights just suck. Sight radius is too short and the front sight post is too thick. I got an MBUS rear sight to put behind my red dot and called it a day for a while. Unfortunately I live in the Democratic People's Republic of New York. So my rifle came with a fake adjustable buttstock and a muzzle break that's as hard to clean as it is ugly and it just pisses off the people next to you at the range. These two things, plus the fact that I feel like my front sight post is worthless and just in the way of my red dot inspired me to start tinkering. I swapped out the stupid AWB legal rifle length buffer tube with a carbine length buffer and spring (that was confusing when I was trying to order parts) for a genuine rifle length system and installed an ACE Skeleton. One problem solved. Next I want to upgrade the trigger with a drop in, pretty sure I want a single stage, but havent decided which one I want yet, open to suggestions. My dream AR would also have an 18" cold hammer forged barrel with a mid length gas system, for a little extra velocity and accuracy, and a free floating rail. Since nobody offers a complete upper like that, at least not that I've seen, I decided to do it myself. Orderd a Daniel Defense 10" M4 rail and the wrench for it, but the 18" barrel with the low profile gas block is back ordered 6 weeks. My current 16" has pleanty of life left so I figured I can stick with it for the time being. Problem is that awsome front sight post again. I was thinking about cutting the top of it off and filing it right down to the gas block to make a low pro out of it, but DD's websight says the M4 rail has an internal diameter of 1.45". I measured my front sight post and best I can tell it would be 1.5" after my mods. I'm wondering if anybody has experiance with kind of thing and also if it's even possible to install a low frofile gas block on my current barrel if the M4 rail doesn't fit over my modified gas block. Also, what's the best "muzzle device" I could install living in this socialist paradise? Thank you to anyone that could help.