Accuracy of Lightfield 2 3/4 EXP

I have an H&R ultra slug hunter 12 gauge with a heavy barrel and am using Lightfield 2 3/4 EXP. I went to the range last week to sight it in and was grouping 3 shots in a single hole, 4 inches high at 50 yards (I could not believe the accuracy of this combination) anyway I ran out of ammo. I bought 5 more boxes of 2 3/4 EXP and went to fine tune it to 2 1/2 inches high at 50 yards according to your ballistic charts but this time I was hitting 7 inches high at 50 yards. I was using the same rest, the weather conditions were almost the same as before and all other factors were the same. What is causing this? I even looked for lot numbers on the old boxes and the new ones but could not find any. I would appeciate any help to rectify this Thanks

Without you suppling me with the lot numbers, it is hard for me to pin down the differences in impact of the different Hybred-Exp you have purchased. It could be as simple as one batch of the slugs could have been improperly stored before you purchased them.

I can tell you that Lightfield uses all one lot number of powder to load one full years production. Any one of the individual lot’s of ammo loader within the same year production will pretty much shoot into the same group.

Point of impact changes can be seen between to different year’s powder production. Each year’s production should still shoot just as good a group but there may be a different point of impact between the two years.

You will find the Lightfield lot numbers on the top of the boxes on the flap that inserts into the box to hold it closed.

Hope this help and good shooting.