I don't think that you can put a 12 gauge barrel on the 10 gauge frames of the H&Rs. I just looked at barrels the other day on their site and you probably have to stick to the 10. Here is a link to their barrel site. click here It looks like you can get a 24" barrel with an x-full turkey choke for your gun for $85. You'll have to send your receiver and forend to them to have it fit to your gun.

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