Thanks for the input. I decided to go with a 12 ga. AYA, having the requisite features: Greener crossbolt, bushed strikers, and side clips. AYA may not be the ideal donor but for a first time, thought I'd give it a try. My plan is to try something like a 45-70, not too powerful. I'm thinking I'll use Brown's concept of making the monoblock as a scratchbuild and save the original barrels. Blacburn....757Arms, indeed has a wide selection to choose from, and seems easy enough to do business with! Bill