OP - I personally am not a fan of QD sling mounts which I note this RRA stock has. Why? Because it's another thing rattle on the gun and another part you need to buy.
Then you get to find that not all QD sling swivels are the same size.
I like threading my sling through the stock. Magpul Moe:
Re milspec vs commercial - The above is commercial and I had to order it online as commercial aftermarket stocks are never on the shelf anywhere.
My Magpul Moe pistol grips have battery storage in them.
If your rifle is already built with a milspec buffer tube, I would look for a milspec stock. If your assembling this rifle yourself, commercial would work just fine.
Be aware a spare buffer tube, spring, and buffer will most likely become a complete rifle in the future.
Then you get to find that not all QD sling swivels are the same size.
I like threading my sling through the stock. Magpul Moe:
Re milspec vs commercial - The above is commercial and I had to order it online as commercial aftermarket stocks are never on the shelf anywhere.
My Magpul Moe pistol grips have battery storage in them.
If your rifle is already built with a milspec buffer tube, I would look for a milspec stock. If your assembling this rifle yourself, commercial would work just fine.
Be aware a spare buffer tube, spring, and buffer will most likely become a complete rifle in the future.