First off I would start with factory loads, then I would use a sandbag under the hinge and one under the butt of the rifle, and fire a group (remember to take your time, barrell heating can cause stringing too). You really have to remember to do everything the same so that the sandbags are in the same place, your hands are in the same place on the gun, rt hand on grip and left holding side of sandbag under butt of rifle. Like JamesB said, squeeze and hold the trigger. I'd check to be sure that the scope mountings are tight. If that doesn't work it might not be a bad idea to try a different scope and just see, you never know. Make sure the gun is going to shoot before you take the time to test handloads, you can't figure out which groups the best if nothing groups.

Then with the handloads start at the listed start charge and work up. What works in one gun may or may not work in another.

Sounds like there can be a lot of tinkering with these NEF/H&R's. I'm actually looking at one now..Nice to know some of the quirks before I get to this point....