AR build choices

[Oreo]

So I'm trying to plan out my build & need some practical advise. Since I'm going to have two lowers, I guess I might as well go on & have two complete AR's so that should make things easier. The first will be a practical battle rifle - 16" barrel fed a diet of M193, so that should be easy enough for me to figure out.

The other one, I'd like to set up to reach out & touch those things just past the horizon. Problem is that here on the east coast there's no real practical place for me to do that kind of shooting so maybe I'm after something I can't have anyway, I don't know. Anyway, here's what I'm thinking...

Since I'm going for distance I guess I should be looking at 69-77gr bullets? Which also means I need a good long barrel to get the velocity necessary for proper fragmentation. So I'm thinking a 24" (or would a 20" be more practical?) Since I'm going for these long heavy projectiles I'll need what, a 1:8 or 1:9 twist? But at 3k fps I'm looking at spinning those bullets awfull fast. Will they hold up? Can I even get 3k fps with a 75gr bullet & a 24" barrel? Can I do it with a 20"? What kind of range would this kind of build be capable of & still get good fragmentation?

Hopefully you can see where I'm trying to go here. Any wisdom is appreciated.

[creophus]

Oreo,

What kind of trigger do you have on that lower that will be configured for long range shooting? That will make a huge difference in your accuracy potential. Also, plan on scoping it with some good glass.

In regards to barrel, I'd say 20" and up will do just fine. Plan on a faster twist rate 1:8 for the longer projectiles. Are you going to use the magazine or single feed? That makes a difference the weight/length of projectile you can shoot as longer bullets won't feed from the magazine.

Can you toss out a number of the distance you'd like to be able to shoot? If you're wanting really long range, you would be better served by a different caliber. Wind can really push those "little" bullets around.

[Oreo]

I haven't defined my requirements that strictly. I'm more or less committed to .223 in an AR platform. I got a bunch of 20rd mags already so I'll be using them. I guess part of my question is how far is reasonable with that kind of a setup? I'd like to be able to shoot as far as is reasonable.

I haven't decided on a trigger yet but I know I'm going to need a good one. Glass as well.

[Gashira]

I haven't defined my requirements that strictly. I'm more or less committed to .223 in an AR platform. I got a bunch of 20rd mags already so I'll be using them. I guess part of my question is how far is reasonable with that kind of a setup? I'd like to be able to shoot as far as is reasonable.

I haven't decided on a trigger yet but I know I'm going to need a good one. Glass as well.

I've got a RRA 2-Stage Trigger in my AR that I'm more than happy with. I spent some time with a Dremel just to ensure that it's smooth as possible.

My personal preference would be a 20" barrel. IMHO anything further than 1000 yards would need a bigger round than .223, so I can't imaging those extra 4 inches would make a huge distance. I'd definitely make it a PITA to haul around though :).

[Oreo]

What about having that extra length for bullet velocity? Gotta get those 75gr projectiles up past 2700fps (at the target) in order to get proper fragmentation right? So even if I'm only shooting 3-600yds isn't that still an issue? I'm asking 'cause I don't know.

[creophus]

What about having that extra length for bullet velocity? Gotta get those 75gr projectiles up past 2700fps (at the target) in order to get proper fragmentation right? So even if I'm only shooting 3-600yds isn't that still an issue? I'm asking 'cause I don't know.Forget about fragmentation. You don't want that. You want expansion. I'm not sure of the difference in velocity in regards to barrel length. I did a bunch of research on 308 velocity with respect to barrel length a while ago, and I've even forgotten most of that.

Keep in mind that there is a practical limit on barrel length. I honestly don't know what it is, but a longer is always superior. I know you want to stick to .223, but if you really want long range, step up to a bigger caliber. 6.5 and 6.8 will use the same AR lower as .223 and are MUCH MUCH better for long range shooting. Sounds like you're not just trying to punch paper, but actually hunt/kill something. The previously mentioned calibers would be well suited for that.

[Oreo]

Well, 99.99% of the time it will be just paper. But I'd like to know that the rifle is capable of more then just fluff. So, I'd like to take this build to the near limits of the .223 cartridge (& platform) & be happy with it. If I'm expecting too much of the cartridge then what are reasonable expectations?