What is the accuracy potential of this weapon? Its got a leupold mk4 scope on an arms base. It seems like its getting more accurate (4-500 rds so far). When I first got it I was geting 3-4 moa out of it. This last weekend was well under 2 moa.

Potential as is, or potential with other upgrades?  Shim the gas system, put it in a bedded stock, add a NM oprod spring guide, and you can get at or below 1 MOA.

As is. Thanks.

You can expect under 2MOA from a Loaded with no other upgrades.  Do you have a wood or synthetic stock?

Proper stock fit, either wood or syn, has a major impact on accuracy in the M1/M14 type rifles. My Bush rifle's groups were cut in half by bedding the stock. Partly this is a result of the action/barrel not slipping around when the rifle fires and partly the need for some down tension at the front ferrule. There's about a half dozen things that improve accuracy on these rifles.

I think a tight synthetic stock or a bedded stock can make the single greatest improvement to accuracy, followed by shimming the gas system.

I had a TRW-barrelled M1A go from 4MOA to 1 MOA just by putting a tight syn stock on it.

The stock is synthetic and seems tight. How difficult is shimming the gas system?

Quoted: The stock is synthetic and seems tight. How difficult is shimming the gas system?

shimming is easy.  The shims are $7 from Fulton Armory.  A Castle Nut Wrench is $35-45 -- a bit pricey, but a good piece of gear to have.  

To shim:  remove the flash suppressor set screw.  Remove  the castle nut.  Slide off the castle nut and flash suppressor.

Next, remove the gas cylinder plug, then the gas cylinder lock.  Then, slide off the gas cylinder.

Next, put the 3 shims on, thickest first.  Put the gas cylinder back on.  Twirl the gas lock back on.  Your goal is twofold:  have the gas port in the gas cylinder align with the gas port in the barrel, and have the gas lock rotate finger-tight to 4 o'clock if looking down the muzzle.  Past 4o'clock, use a wrench to turn it to 6 oclock.

Hint:  if at first the gas hole and gas port align but the gas lock doesn't spin to 4 oclock, try reversing the gas lock.  If that doesn't work, adjust shims as necessary.