I had the same delima. Not a lot of folks shoot .410 seriously, but if ya haunt some of the skeet ranges, quail walks, etc, ya can pick up enough to get ya started. I ended up posting in about a dozen different forums under WTB, bought a bunch from a fella out of Nebraska. Any way, good luck. As far as the 2 1/2" vs 3"--almost all mine have been 3".