Just finished my first build (an AR 15 pistol) and have the itch to build a 308 for my son to deer hunt with.  Any and all suggestions welcome.  

Questions
Does the upper and lower have to be a matched set...same manufacture?
Will my AR tools and clamps work?
How many parts are interchangeable between a AR10 and AR15...trigger, safety etc.?

I'm sure as I work through this there will be more questions and searches!

I'd recommend sticking to one mfg for these parts... upper/lower/BCG.

ETA- my Aero lower used standard AR15 lower parts except:

Front and rear take down pins
Bolt Catch (plunger and spring standard AR15)
Mag Release Button (spring and mag release standard AR15)

Some manufacturer's uppers and lowers will work with others.

You would have to either read the fine print on each part, contact each manufacturer to ask, or find examples of your proposed combination on forums like this.  I'd do all three.

The majority of AR10/308 receivers are larger than AR15's, so some of your AR tools may be too small...especially the clamps.

You need to be careful and do your homework with compatibility of parts.

I'd recommend reading the 308 FAQ.

make sure you use dpms compatible parts. armalite and dpms do not interchange. do not order a barrel nut wrench until you decide on a hand guard. the hand guard may have its own dedicated nut wrench. my utg pro came with a wrench. none of your clamps will work. the trigger is interchangeable between the two too bad the rest of the lpk is not. I have a dpms upper on a palmetto armory lower.

My.308  build used a DGW upper and a PSA P-TAC lower.  Upper and lower do not have to be a "matched set" from the same manufacturer but going that route will pretty much guarantee correct fit and matching exterior contours.

Even being "DPMS compatible"  does not guarantee that certain parts will fit.  While PSA claims that their lower is DPMS Compatible, it is not.  
1.  The takedown & pivot pins are unique to the P-TAC lower.  DPMS parts are too short and have different detent slots.
2.  Same for the bolt catch.  While all .308 catches are longer horizontally than a 5.56 gun, the P-TAC one has a unique tang for the mag follower to contact with.

For the most part, all the fire control parts are interchangeable with standard AR-15 parts.  Buffers and buffer springs are unique to the .308 due to more recoil impulse.  Charging handles for the .308 appear similar but are much longer to accommodate the longer upper receiver.

Another suggestion....use an adjustable gas block so you can fine tune your build to be fully compatible with whatever ammo you choose to use.

Most of your pre-existing 5.56 tools won't work with the .308.  The receivers are much larger, so vice blocks won't fit.   The spacing between the pivot and takedown pins is larger so holding fixtures won't fit.  All the carrier assembly components are larger so some bolt tools won't accept the .308 bolt.  The barrel extension and lugs are different than a 5.56 gun so things like reaction rods and extension wrenches won't fit.  Barrel nuts are larger and not common to 5.56 guns.  Accordingly, barrel nut wrenches may differ.

Obviously, pin punches and basic hands tools remain common for both platforms.

Building a .308 can be challenging if you mix up too many manufacturers parts.

Here are the results.....

I recently rebuilt using a matched Aero M5 set.  Damn good set.  I reallly like the use of the screws for bolt catch and forward assist

In the last year I have built 4 308's for family.  Two were PSA PTACs, and two were Aero Precision M5's.
Parts interchangeability between various brands is a real consideration.  To avoid problems, I would suggest sticking with uppers and lowers from the same company.  My first two 308's were stripped lowers, and I had quite the learning curve about specific components being required for specific brands, I still have some excess LPK parts to remind me of that.  I didn't notice any substantial difference in quality between the two manufacturers.  
Here is a look at my latest builds so you can see the difference between PSA and Aero Precision. (I use 10 round mags for ease of storage in the gun safe, I like my stored rifles to have a magazine with them.)




I used barrels from Anderson rifles, Sprinta Precision, KAK, and PSA.  I used BCG's from AIM surplus.  The only tool I had to get was a vise block for the 308 (I made one out of a 2x4), and I had to modify a barrel wrench to fit the barrel nut for the 308.  Other than that,  the process for building a 308 is identical as a standard AR.