Dear BoatBum,

Yes, those are chopper lump barrels and that is the seam showing in your photo.

One half of each barrel lump is an integral forging with the barrel tube.

I hope that you will not mind by saying that your Dad was wrong in his assessment of the gun.

It is a best quality hand built gun from gun making’s golden age.

As to the bores, you need to get a gunsmith with a wall thickness gauge to give you an opinion once you have been able to scrub out any loose rust.