I've done it with a couple of nice full choke Winchester Model 12's and a Remington 870 and even some good quality over and under guns. Not complicated, not expensive, and if the opened up 12 ga. choke restriction is 0.025" or less after alteration, and the barrel is otherwise sound and not too thin, it is a safe and effective modification that allows the shooter to use steel shot. Guntech has the costs explained very well. You decide if it is worth while.