Barrel and Optic for 308 AR build

[ColoradoMinuteMan]

I ended up getting a deal on a Aero Precision "M5" blem lower. I've been wanting to build a 308 AR for a while now so I figured I'd give it a try. I've been an iron sights guy my whole life but I have an eye condition that is progressed to the point where precision beyond 25 yards is difficult without magnification.

My main purpose for this rifle will be to train myself on optics. I realize I could just as easily do this with my AR15, but if I'm going to train myself from 100-500 yards I want to be lethal at all ranges. I also realize there are flatter shooting cartridges than 308 for that range and beyond that I could use in my M5, but I'm choosing 308 for compatibility with 30-06 projectiles since I'm a reloader.

I'm having a hard time deciding on a barrel. The more I read the more I see very little difference between the accuracy and velocity produced between a 16 and 18 inch barrel when it comes to 308. Due to the fact I may one day get the itch to use this for hunting I'd like to keep it relatively light. That would probably leave me with a medium or "government" profile 18 inch barrel if I went with 18. If I went with the 16 I could use a heavier barrel and get comparable weight with the lighter 18. Does anyone see a real advantage in an 18 inch barrel over a 16 that might put me over the edge? Also, does anyone have experience with a medium or "government" profile on an 18 inch 308 AR barrel. I'm curious about accuracy in relation to heat in particular.

One barrel that has my interest is the Ballistic Advantage 16" .308 BA Hanson Midlength Premium Barrel. I've also been eyeing the 18 inch medium contour from Ballistic Advantage. Anyone with experience with either of those that can share some insight?

The next question is optics. I been about a variable rifle scope. What has caught my eye are the Vortex Viper 2.5-10x44 in either HS or PST. I looked through the PST at Sportsman's Warehouse and was really impressed with the glass compared to similar prices Leupolds in the case. In new to scopes and am still deciding if I need the exposed tactical dials or not. It I did love the glass. Does anyone know I the PST and HS have the same glass or not? What are your thoughts on the 2.5-10 magnification range for a 308 with a 100-500 target range? Remember that my eyes aren't perfect two the so I probably need an "x" or so magnification compared to those who can correct to 20/20 vision because I can only correct to 20/40.

Thanks for the help.

 

[NWcityguy2]

The typical 3-9x scopes, or something close to it, are great when distance don't drop below 100 yards. I know that technically people can shoot incredible distances with less magnification, but having more magnification will generally make for a more confident shot, if your rifle has enough stability. Higher magnification will also aid in shooting at targets that blend into their backgrounds.

Realistically, for 100-500 yards, the minimum you'll want is a scope that can hold zero, is usable at maximum magnification and has a bullet drop reticle. Bullet drop reticles aren't perfect, but with some experimentation, they get you pretty close. The other budget option would be a fixed 10x power, you'll lose the ability to zoom out, but have a greater ability to dial in shots within the same price ranges. That is a better option for going further than 500 yards.

I don't have any experience with the Viper, but I use a cheaper scope to shoot out to 500 (full torso) on my AR15. I've got a Weaver Super Slam 2-10x42mm, which sell for around $250-300 at Natchez. Just using the BDC, I get out to 400 yards. No adjustments needed. The problem with my scope, and most "lower end" tactical scopes, is that adjustments aren't perfectly exact or repeatable, just very close. So for a big target at a range where adjustments are needed, I can dial it up and usually be there on the first shot. Then I can dial it back and be very close to my original zero. It is a workable solution when only going from one adjustment and then back again, but falls short when wanting to adjust things all over the place.

 

[Robert]

I went with an Aero Precision 18" barrel but have not finished my build so I can't say how it shoots yet.

 

[henschman]

I've had gov't profile barreled .308s before, and don't care for them. They are needlessly heavy, because the heaviest part of the barrel is out on the end where it doesn't do any good. I had an M&P 10 with what you might call a medium profile barrel, as it starts out heavy and tapers to a pretty skinny profile, and it was much more handy for hunting and carrying in the field. I think if I were building a .308 and wanted to hunt with it, I would be looking at Faxon's .308 medium taper barrels. I have two barrels from them in 5.56, and they are really nice. Link: http://faxonfirearms.com/barrels/ar-10-lr-308/. If you have a suppressor or plan on getting one, I'd get the 16". If not, I'd get the 20". A 16-18" .308 is LOUD, no matter how you slice it. They are just plain blasty, and not particularly pleasant to touch off in the deer woods with no ear pro. You might be able to swing one of the shorter barrels for hunting with one of the linear compensators that direct blast down range, like the BRT Covert Comp. I have one on a 16" 6.8 and it does what it's supposed to do.

As far as optics, yes, a 2-10x (or a 3-9x for that matter) makes a great hunting scope. I'm focusing on that role since you didn't really say any other specific roles other than learning to use optics, which doesn't really narrow things down much.

Some others you might look at are the Weaver Tactical Grand Slam 2-10x40 if you want a more budget friendly model that still has good Japanese glass, and the Leupold VX-R Patrol 3-9x40, which has good glass (VX3 level) and the fantastic Firedot TMR reticle.

 

[JDGray]

Pretty happy with my Rainier Arms 18" barrel, shoots under moa groups for me.

 

[ColoradoMinuteMan]

Thanks for the feedback. It's good to hear about your success with the Faxon barrels. The are also on my list of possibilities. My observation on those is that they have a near pencil profile by the time the you're past the gas port. I suppose it has size far enough forward of the port to provide enough protection against deformity from heat. I'm not much of a mag dump kind of a guy anyway so heat isn't a huge concern for me.

Faxon seems to get good reviews. The only negative review I've ever seen was early on in production it sounds like they had a couple of issues they worked out. It sounds like they owned up o those issues and worked with people to resolve it which shows that they care about the product and customer satisfaction. Thanks for sharing that I may look a little harder at that option. I see they have a 5R option as well.