I now have reloaded a bunch of 12 gauge based on my initial loads, and components I have…
I’ll offer a bit of advice learned the hard way.
Don’t reload a huge surplus of shells or cartridges. Only reload what you’ll use in a few outings. Things happen!
My first shotshell reloader was a MEC 600 that I got in the 70’s. It worked fine for 12 gauge when I only shot occasionally. When I got serious about shooting skeet and trap in the late 90’s, I bought MEC 9000H’s for 12, 20 and 28. I got a Grabber for .410. Back then, I could reload a box of shells for $3 or less.
I burned through a lot of 700X and 296 powder. Here are just some of the empty 12# kegs of 700X I recently cleared out of my reloading area. I’m in the process of making room and throwing out junk.
Yup, that represents 120 lbs of powder! I went through a lot more than that.
Back to my original point…
When I was shooting 4 days a week and firing about 200 shells per day (some for score and others for practice), I thought it was a good idea to build up a large surplus of shell in my off time. I had about 10 flats of 12 GA stocked up. At some point, I developed an intermittent problem where the powder charge didn’t throw consistently. Many of the shells were fine, but others were “poofers”. I missed some birds because of the issue and would only use the rest of that large batch for practice.
If you’re shooting a lot, you’ll probably buy previously owned powder and primers when you find a good deal. You can occasionally run into problems there too. Even factory new components sometimes come under recall.
Store your components in a cool, dry place and only load what you need.