I have shot the same H4831 and some older H4831 sc since I worked up the loads for my 270 and 7 mag for Nosler bullets back in the early 80's.

I loaded up a batch the other day from a new can of H4831 sc and got random eradicate shots at 3 inches in both rifles. Velocities for the 7mag were faster too but not like the 270.

The 270 usual (2830 fps ave) the same load gave me 2974 and 2992 fps. I rotated the shots just to ck the machine. No shell issues nor flattened primers.

These loads have all shot well from one hole to well under an inch group.

HOW TO FIX:

I was going to pull all the bullets and start over but not a lot of time to workup loads.

I have about three pounds of H4831 sc left from different batch numbers.

Do you see a better solution than just dumping all the and out and mixing the three cans together for a more even powder then rework loads up?

WHAT HAVE YOU FOUND WITH THE DIFFERENT CANS OF h4831 sc?

How much did you have to lower the grains of powder from old cans to keep your groups tight?

Suggestions?
Thanks Jim

You're just going to have to start over, just the way it is with new powder. If rifles haven't been shot for a long time, check action screws and scope attachments. I doubt you will get an even mix if you combine the powders.