Ok im thinking about getting me a Bushmaster m4 type patrolman's carbine with the A3 sights so i have a couple questions about it before i make the big step and getting something i thought was what i wanted. i want options which is why ive been wanting to get an Ar style rifle because i heard the combination's are pretty much endless when it comes to personalizing the rifle. 1. am i going to be able to remove the front sight on the rifle so they don't get in the way of some good optics? 2. are all of bushmasters AR style rifles made from the same type of material because it seems i see some that are really black and some that are made of a lighter looking material. (could just be the lighting in the picture) 3.i really like the thicker fore end grip style they have on the colt rifles am i going to be able to change the fore end of the bushmaster? 4. are the bushmaster barrels interchangeable? say if i wanted to go to a longer barrel if i felt like doing longer range shooting? pretty much what im asking is what parts of the rifle are not able to be changed? or is this rifle pretty much a fully customizable platform which i can change to suit any style of shooting i want as i progress. sorry for all the questions im just very new to the Ar style rifles and i just want to know before i spend the hard earned money on it. Thanks!