The comment earlier about a .410 giving better confidence to a .243 made me laugh a bit..my rifle is a .243win, I was hoping to take it up north for whitetail sometime alsohaha
But..again..not worried. I've watched a .243 take deer out to 350y..probably even further if accurate enough..I'm not..ill be a 100-150y limit kinda guy for a bit yet
Plus..this whole 410 thing so far is theory. I do own a 12g 535 with a rifled barrel
If it's just accuracy you seek, I'd just get sabots for your 12g and put your fixed optic on that.
IMHO