Get a DPMS GII with the 24" Bull barrel
Stamp Creek,
If the purpose of this rifle is to complement your bolt gun as a precision rig, i would assume that to mean that you'll also want to shoot it competently at distance.
I would also assume that your "carry", "mobile" rifles will be the 556 guns you already own, and not this one.
If so, save yourself, time, money, energy and frustration and go to a turn key solution...
DPMS G2 BULL 24'
Here again are the reasons why this is what you want:
1. Cheaper than building your own. The price listed is MSPR, i believe they are on sale in the $1,100 - $1,200 range
2. It is an improvement over the current generation of large frame ARs on the market.
3. It will come with a warranty compared to piecing something together.
4. No wait times...this is already in stock at many dealers.
5. It has a 24" bull barrel. This is what you NEED in a precision 308. Forget short barrels. They rob you of velocity, allowing your bullet to get blown around significantly. Figure 15-25ft/s per inch loss in velocity. There is a reason why people that shoot distance at the national levels run 30-32" barrels in a 308. 24" is as short as you want to go. You will want more barrel length as your competence increases and you bleed points to the competition due to wind drift.
6. The DPMS rifles seem to have chambers cut deep enough to run heavier bullets...they also have a reputation for being accurate. There is always the occasional person who gets an abortion of a rifle, but really, that's also true with every manufacturer.
Following is my advise for shooting longer ranges:
You've chosen a 308. its a marginal cartridge for long distance shooting due to limited case capacity.
To make the 308 work, you need:
1. long barrel...longer is better. as i said, palma shooters, F-class shooters, etc use 28-32" barrels on their rigs. This will get you the absolute highest velocity available from a powder charge without having to push pressure limits as you will if you elect to run a shorter barrel.
2. High BC bullets. I know your avatar is of a 175SMK. That bullet while accurate, and a good choice for midrange (300-600yards) is outdated and is not adequate or desirable for long range work. Your focus should be on bullets such as Hornady 178gr HPBT (not AMAX), Hornady 208AMAX, Berger Hybrid/VLD bullets in the 185, 190 or 210 weight classes.
3. Powders that will drive said bullets at a high enough velocity to exploit the BC (Varget, IMR-4320, RL-15, RL-17, 2000MR etc). The last two will give you the highest velocities however, they are temperature sensitive.
4. Wind reading skills. This is the most important and hardest skill to develop. It takes years of shooting with a coach to get very good at it. This is what separates the top shooters in the world, and in many comps the difference between the top 5 guys at a match are measured in X count...that is to say they had the same scores, but some guys were better at judging the wind.
