I am starting to do the changeover from 5.56 to .308. Im not trying to start a debate about whuch is better... I have decided the bigger cartridge is (for me) advantagous.

I am in a rural setting. I own 7-acres of a mix of pasture and wooded area. For hunting and practice I can shoot out to about 300-yards safely. Possibly a bit further if I HAD to. I'm 56-years old and my eyesight isnt what it used to be ( my NF scopes make that pretty much a non-issue) but I'm still strong and steady.

Lets just SAY I needed to be able to defend the food I grow myself and the house that keeps us sheltered. I am in no better / safer place than I could be (save for a hole in the ground)  so I am not bugging out. My family and my gear is going to stay right where we are. Also I have no desire to go running through the woods tracking some big game into the mountains. Thats not to say I wouldnt hike a couple of  miles down to the river areas to harvest deer (or fish) to feed the family.

I currently have a few 5.56 rifles  and just got my first AR-10 style rifle with a16-inch SS barrel (should be useful out to about 600-yards according to my research). I am about to order another AR-10 style rifle and am trying to decide whether to go as lightweight as possible or SASS style to reach out from the front porch. It seemsthe lightweight gun would be more "practical" - being able to carry it around - but if I'm not out running the moutainside and just staying put would the SASS offer better LONG range effectiveness. ? (assuming the SASS has a bit more range and accuracy). I know both would do a fine job and (hopefully) never be used to their full design potential....hence the question...in my circumstance how long range is long enough...?

And I realize they are very close and the cartridge has its limits ..... and the difference in rifles is narrow ...I'm new to all of this..and am looking for thoughts....

So you are protecting you pasture and garden? Out to 300? So you are talking about popping a deer in your garden? Does your state allow ar15s for hunting deer (as in semi auto and 22 caliber)?

Technically speaking, the 556/223 round with the ammunition selection we have today, is an effective round for deer out to 100-150 yards. As far as 556 vs 308 rifles. I'm a believer in starting with a rifle that is a whole new class. If you are gonna get a 308, then getting a rifle that full takes advantage of the greater performance of the 308. If you already have an AR that will cover your land then get a 308 that will cover everything beyond.

I'm trying to make sense of your question. You are just thinking about getting a second 308..? Like I said above...if you already have a generally lightweight 308 then get something that sets the new rifle apart. Look at something like a heavy stainless barrel/varmint or a SASS or a Long range Lite model....

I admit that my question is rather .....vague.... so I will try and be more specific.
Yes my state allows use of .223 semi-auto for deer and I have that covered nicely out to the understood 150-yard effective limit of the cartridge.
I currently own a DPMS G2Recon with 16-inch SS barrel that should reach across my entire property (and farther). It is a bit heavy...but properly retro-fitted could probably fill the role of a LR rifle...(maybe I just answered my own question...) but its too heavy to just strap on and head on down to the prime river hunting grounds...but maybe with some changes it could fill both roles....But I was thinking 2-rifles for 2-purposes.  One to carry and one to stand pat with....

I have a 16"" and a 24" AR10. After having the 24", I am starting to believe it's overkill for the AR10.

There is not that much performance difference added over a 20" barrel, and it's a whole lot more unhandy.

I would say a 24" bolt gun is more maneuverable than a 24" Ar10, but there isn't a whole lot of difference.

For really long shots go with a 300 Win Mag.
For the shots in the effective range of a .308, the 20" is fine.

Maybe this is the wrong assumption, but it is my assumption that light and handy and AR-10 don't really go together.  In fact, almost anything in .308 that is a semi is not going to be all that light.  

I think the thought of setting up your AR10 for long range isn't the worst idea.  And then you could do something more handy for the closer in shots.  Either a 5.56 AR or something else.  A bolt gun in .308 with a smaller scope, like a 1-4.  Or a good lever gun in .30-30 could cover 300 possibly.  

I don't know.   If you ask me, a bolt gun is hard to beat for a "I got my bases covered against animals" gun.  A sporter with the right scope can probably do it all.  Except the part about it being a semi and have lots of ammo on top of course.

DPMS SASS is kinda heavy.  I think a good compromise would be their G2 hunter.



I would keep in mind that shot placement is far more important than caliber.  I have to problem shooting 5.56 from 0-500 yards.  



If I was really interested in extending range I would look for a .260 or 6.5 Creedmor.

       
 

In my limited experience I would have agreed with you about the oxymoron of AR-10 and lightweight -  until the new DPMS Gen 2 guns...... their MOE weighs in at 7.5lbs and feels awesome. With even the SS barreled Recon in at 9.5lbs its not AWFUL and recoil is not much more than my 5.56 piston gun. Its these G2's that have me re-thinking my collection......

IMO the big issue for me is ammunition cost. I can afford a lot more trigger time on my 5.56 guns.  The G2 has made a huge difference on weight though.  Split times will also be lower with 5.56 if you have to use it close in.



 

Weight is a serious consideration with the AR10s over the AR15.  Those that say weight isn't an issue do not use their gear because weight is always going to be a consideration.

I've owned three AR10 and can tell you they shoot well.  Biggest drawback is weight....you would be fine with a 16" 308 at the distances you are looking to shoot.

If I were you, I'd keep it in the AR15 family and go with a 6.5 Grendel or 6.8SPC for that range and for more power compared to 5.56.

For what you are describing, there is nothing the 308 will do the 223 cant do. 300-400yds is not long range, and is well within the killing envelope of the 223. Whoever dreamed up this 150yd limitation on the 223 for effectiveness clearly has no clue, or experience.

My lightweight 308 AR will be a 16" larue predatAR. Pricey, but you get what you pay for.

How many people will you have behind guns should you have serious trouble? I imagine you are talking about a lawless situation caused by natural desaster or whatever. If you have people in the house or elsewhere who might act as overwatch for folks tending to the farm an SASS or three might be handy. The person or people out in the field working would be better off with lighter rifles. I saw some 20" .243 armalite AR-10s for sale awhile back and I considered getting a couple.

When it comes to shooting moving targets far away velocity is your friend.

Plenty of folks use 18" .308s to shoot to 1000 yards and further, but that takes alot of hard earned skill especially when you are shooting at moving targets. At ranges of 500 yards and beyond your biggest problem is putting the bullet where the target will be when the bullet gets there while also adjusting for wind, cosign, drop and whatnot. That is best learned by shooting at moving targets. Alot.

Hmmmm......you think the 16" is a little heavy... I'm sure it is still capable of shooting 600 yards easily. So if you are thinking you got your LR covered then maybe look at a S&W MP10 or a PSA with a 16" or 18" with Midwest rail. Or a DPMS Lite Hunter (they are coming out with a 16" Lite Hunter too which might already be on the shelves).

One of the reasons for going .308 is that I have found quality ammunition to be plentiful and reasonably priced - If your diligent....and over the last few years I have collected a small stash of REALLY good stuff (Hornady / Black Hills / Hirtenberger / Federal / Barnes /Speer) at pre-panic prices...a good mix of bonded and BTHP rounds .

If he's already on board with the G2, I see no earthly reason to go backwards to the M&P or a PSA.

I'm assuming the one you have now isn't 7.5#, or is it?  If it is, than you're probably not going to get much lighter than that in a .308 platform without having recoil become an issue.  You could get a remmy 700 youth or that 16" ruger makes, and have it be real light with just a small optic on it, but I would think it's going to kick a lot and your follow up shots will be slow.  But if you were wanting to stick with .308 and have it be real light, that could be an option.  I wonder about an SBR .308 AR.  That could be sweet.  You could do an SBR and see how light you can make a lil .308 carbine and show everyone else how it's done.  I didn't know you could actually get an AR10 down to 7.5#.  That seems pretty good.  

Or I'm imagining you're thinking of going the other route and getting something with a longer barrel to make longer shots a bit better, or easier than perhaps a 16".  I have no experience other than that a 16" barrel can be real accurate, but you're losing some velocity so a longer barrel probably does .308 better for long range, in any load.  If you put some heavy bullets in there, they start out a little faster and then will shed velocity later on the far end than a shorter barrel.  I actually didn't know that 1K in an 18" barrel for .308 is possible.  I thought they start to go subsonic and wobble.  I realize the real heavy loads with match bullets are the way to go and shed velocity slower, but you're still starting out slower so.........

You come to any conclusions about what you wanna do?

The current .308 I have is the 8.5 lb Recon -which seems just a tad heavy for a carry to the river gun ....and I havent mounted an optic on it yet....

So here is what I am thinking......

I ordered a DPMS AP4-MOE that weighes in at 7,25 lbs to srrve the light weight role. And now I am considering setting up the Recon with good scope and bipod and hope it likes a lighter grain bullet to keep the velocity out a little farther. I believe both rifles (16-inch) will shoot as far as I can and maybe the Recon SS barrel will be more accurate at distance.  Being a heavier setup I will keep it more of "an around the farm"  gun and use the MOE to lug around. As funds allow I may get somethingwith a longer barrel to try outt...like the SASS...

One thing I did realize is that I am going to need to keep a 5.56 in the safe for sure as my PVS-14 wont handle the recoil of a .308...and I haven't setup a helmet/mount for it yet.....not ready to scare the family / neighbors with all  that just yet.....

If you already have an AR-10, and you're looking for a fairly capable 308 that's a lighter weight, you should take a look at the Ruger GSR or Mossberg MVP.

I've got a GSR and think it's fantastic.  It's not as capable as a AR if the horde is coming over the hill, but it would hold it's own in most encounters.

Here is what I do.  I have 2 ranges (that i like) near me.  1 is real close but only 200 yards (but NEVER busy).  this 1 I use for reloading / work ups and finding real basic data for my rounds.  Im at this range more often then not.  The other range has a 500 yard range.  This 1 i will use to find/confirm ballistics at 300-400-500 yards.  There is another range that goes to 800 yards, but its full of range nazis and u have to be part of the super secret squirrel club to even use it.

as far as weight... i think my rifle, with scope/bipod/20 rnd mag has to be flirting with 17 lbs.  But i also built it as a bench rest.  I think the 22" barrel alone weighed in at 7 lbs.

Yeah you want to keep your night vision on a 556 rifle or buy lasers for your 7.62 and mount the NV on your helmet. Gen III nightvision rated for .308 recoil is going to cost you. If you plan to set up a 308 for night work I would suggest a thermal device over passive night vision.

I have limited experiance with the two technologies, but thermal is great for finding stuff in the dark.

What I did was sell my AKs kept three .223 ARs and added a DPMS LR 308 for the larger caliber. It has a Springfield 1st gen Sniper Scope and is very accurate. Have shot a lot of deer with it and though its heavier than the others is still quite manageable for me at 63. I use the .308 for field hunting at 300 plus yds





and a .223 M4 with an ACOG for close in stalk hunting.



Hypothetically I could use the same combination of rifles for defense. I am capable at 500yds with the .308 and can use the .223s for up close stuff. I hand load for all of them. Just about any quality 150g hunting bullets does well in .308 (but the 168g  Sierra Game Kings are outstanding) use 75g Vmax for stalk hunting and use 55/62g fmj for range and whatever.

Very nice - and practical as well.

Thank you all for reponding - keep the thoughts coming....