[deathkricket]

I am gathering every thing i need to build my first AR-15. I am going with a rock river arms 20" standered A4 upper with chromed bolt carrier group, chrome molly 1,9 twist barrel to take advantage of the 5.56 being shot from the correct length barrel. For the bottom half i am going with the rock river arms lower with a two stage trigger and mill spec operators 6 postion stock. i will also be getting the quad full length rail for the front. this is my first build and hopfully my last, i have never messed with this platform outside the millitary so any thoughts oppinions or sugestions are very welcome.

[mjkeat]

Are you going after the Basic Training type M16A4 look?

[deathkricket]

Im not going after any "look", out of a 16" car the 5.56 does not "tumble" and yaw when striking a target as intended, the point of 5.56 round was light weight high speed, to work as intended it needs to be start at high speed, out of a 20" barrel the muzzel velocity is a little over 3000 i think around 3100 or 3200, out of a 16 inch its around 2700 to 2800. the 5.56 was ment to be shot out of a 20" barrel hence why the marines did not switch to the M4 and still use the M16 because of the loss of energy and "tumbling effect" that comes along with 16 and 14" barrels of the M4. I am going to put a tac light and a redot and a front grip. I plan on using it as a target/plinking/zombie killer. Incase i ever have to grab it for home defense i want the 5.56 to work as intended. I am however still debating between a 16 and 20" barrel as i am not going to order my parts till next week.

[mjkeat]

Im personally seen what a 5.56 out of a M4 will do to a human, multiple humans, and feel very confident that the round performes just fine.

Either way it'll be a cool rifle. Im looking forward to seeing the end product.

[Quentin]

deathkricket, since you're still considering barrel length it's pretty hard to beat a 16" midlength LW barrel profile. These tend to have a 1:7 twist but that should work well down to 55gr. The longer barrel with its greater velocity shines when you're reaching out beyond 300 meters but inside that range most of us are quite satisfied with a shorter barrel and its convenience.

RRA may not have such a beast but Bravo Company sure will - in LW and govt profile. Well, if in stock.