I recently bought a 308, nib, went to the range, using rem cor loct shot a three shot ragged hole, went back the next time same ammo different box, did not shoot near as well. any one experience this? I normally hand load, but had the rem ammo thought I would use, now hand loading.

I have never experienced that but I always try to buy the same lot number for consistency from box to box because I have heard of other people experiencing that.

Humidity, wind and temperature. Leaving ammo in the sun can do it. Even how much coffee or Mountain Dew you drink.
JCB has a point also. Different lots may not even use the same powder. The guys who are serious about match shooting .22, where you cannot reload, will purchase a couple boxes out of several lots. They will then order as many cases as they can of the one that shoots best out of their rifle.

First 4 year I hunted I shot 130 grain rem corlocks out of my 270. Every year I had to move the scope when I would buy a new box of ammo. I always thought the scope lost zero over the summer.

I started handloading my 5th year and have never had to move the scope unless I changed loads. At 100 yards even going from old to new brass, different lots of bullets and powders, and different brands of primers have never changed anything enough that I moved the scope.

Biggest reason I ditched Remington ammo.

If you are shooting factory ammo when you find a load that shoots very good buy all of that lot number you can. The next lot might not even use the same powder from what I have read.

Reloading you are much more in control still have had to make changes to the load when changing to a different lot of powder or cases to get the same results.

like I said, normally reload, before I started, always had decent results with cor loct ammo, this was 150gr, now loading 168's and shooting the ragged 3 hole again