I've got a pretty good grip on most questions relating to AR's, but I can't figure out where is best to use/mount the quick release sling mounts.

There is one on the back part of my Magpul stock, there is one on the rear of the lower receiver and I've installed a key mod QD mount on my rail, currently just forward of the lower receiver.  So my question is, what is the conventional wisdom for when and why you use each of these mount locations, and I've noticed some people mount their sling attach points at the very front of rail.  

I'm open to any input anyone is willing to share.  

Thanks

If you're right handed the best QD location for the front sling mount is on the left hand rail, closer to the receivers, not the muzzle. For the rear just use the stock. See if that works for you and if not, let us know.

Why use the stock mount instead of the receiver mount?

I missed that you had that one. I'd prefer that one over the stock.
But since it will be closer to the front of the rifle I'd move the front one further toward the muzzle. Try it out in different locations on the left hand rail and see if you find something you like.

I have found that if you are using a two-point sling, like a Vickers, the best place is to get the mount out as far to the front as possible, to avoid getting tangled up when you are reloading.

Topic Moved

That depends... do you want to use your sling only as a carry/retention device, or do you want to be able to use it as a marksmanship aid too?

If the latter, you will want to move the front attachment point just forward of where your support hand grips the handguard in the prone position.  It will then work as a hand stop in sling-supported positions.  For more dynamic close quarters shooting, you can grab the handguard forward of the swivel.  For the rear attachment point, just play with it and see what you like best.  I always just attach the rear of my 2-point slings to the stock.  On some stocks, it carries better if you attach the rear of the sling to the opposite side of the rifle from your body.  Other times that doesn't work well.  You just need to try it both ways, move around a little bit in it, and see what works best for you.  

Here is how I have most of my rifle slings set up: