Advice on Configuring Two AR-15s

[ratboy]

I'm fairly new to the AR world. I've had a Stag Arms 3G for about a year and half and really like it. I've decided that I "need" two AR-15s and was planning to buy a PredatAR and OBR 5.56 from Larue and keeping two of the three ARs I like best (or giving one to my son or daughter).

I want one AR for tactical shooting/defense, steel shooting (w/.22 conversion kit), plinking, and for my son and daughter to enjoy shooting (they are 11 and 12).
I want the second AR for longer range shooting with a scope for varmints and such (mainly prairie dogs). I am assuming that if I had a 3x magnifier behind my red-dot, that that would be insufficient for prairie dogs. I debated getting an AR-10 (for longer range shooting), but don’t see a need since I already have a 300WinMag (and .270) that I primarily use for hunting.

I reasoned (probably incorrectly) that I would want the tactical rifle to be light and short, so I ordered a PredatAR (lighter weight barrel that is accurate until it heats up). I ordered it with a 16" barrel.

I was going to order an OBR 5.56 at 18" for the longer range shooting.

I am now wondering if I made a mistake and should do the following:

Tactical shooting - OBR 5.56, 16" barrel. Weighs more. Shoots the same when dumping a magazine and heating up.
Varmints / Longer Range Shooting - PedatAR with 18" barrel. Weighs less for toting around. Typically won't dump magazines, so will shoot consistently. Might be easier for my boy to shoot because it weighs less.

Here are some questions for you experts:
1. Comments on my new line of thinking?
2. For varmints, would you go with an 18" barrel or a 20" barrel?
3. Is Larue a good selection in terms of moving to a higher end AR-15?
4. Is my assumption putting a 3X magnifier behind a red-dot is inadequate for prairie dogs a valid assumption?

Thanks in advance for your feedback!

[Tim K]

.223 sucks in the wind, and more velocity makes it suck less. Go with all the barrel length you can tolerate. Barrel quality is more important than length for a precision AR, but given a choice longer is better.

Scope magnification requirements depend on both target size and range. 3x is plenty at 100 yards. How far away do you want to shoot PDs? A more important question is how you plan to deal with elevation. Will you hold over at 400 yards or dial your scope. Most LR shooters hear dial for elevation, and that would be my recommendation.

There are a zillion choices out there. Here's one.

http://swfa.com/SWFA-SS-3-15x42-Tactical-Rifle-Scope-P62238.aspx

[ratboy]

.223 sucks in the wind, and more velocity makes it suck less. Go with all the barrel length you can tolerate. Barrel quality is more important than length for a precision AR, but given a choice longer is better.

Scope magnification requirements depend on both target size and range. 3x is plenty at 100 yards. How far away do you want to shoot PDs? A more important question is how you plan to deal with elevation. Will you hold over at 400 yards or dial your scope. Most LR shooters hear dial for elevation, and that would be my recommendation.

There are a zillion choices out there. Here's one.

http://swfa.com/SWFA-SS-3-15x42-Tactical-Rifle-Scope-P62238.aspx

I'd say 100-200 yards for prairie dogs. They're further away than where I used to shoot them as a kid. My preference would be to dial in -- especially for static targets like prairie dogs. That scope you pointed to looks nice -- I'll look into it. You know anyone that has one? What do you think about Nikon scopes?

[spyder]

My advise is to get an AR10 and have it rebarreled in 300wsm, then sell your other hunting rifle.