Monoblocking has been done for a very long time now, having been initially tested and proven a long time ago by Beretta; time has proven that it works and works well. However, it does have at least two drawbacks: 1. The final product has a distinct seam line between the joint of the monoblock and the barrels, and 2, one has to twist barrels into monoblock, if partially threading them into monoblock, or has to insert them into monoblock, if simply soldering them full length into monoblock. Regarding #1, with skill, as explained in W. Ellis Brown's book, converting double shotguns to double rifles, one can peen and blend monoblock/barrel seam so that it is invisible, or nearly so. The British and some others, have learned to mini TIG welding, to weld up the seam, so it is no longer an issue. Regarding #2, for double rifles, it is always desirable to have firing pins as close together as practical, so when using monoblock system, one can't get firing pins any closer than monoblock dictates; shoe lump, on the other hand, allows aforementioned seam to not be an issue at all, and allows distance between firing pins to be closer than with monoblock. Ellis Brown has, indeed, been doing some of the shoe lump system, he has told me, since writing his book, and intends putting some of that new information in 3rd edition of his book, if he ever finishes that edition. The shoe lump system is adequately strong too, suitable for double rifle conversions, as it has been used through history by some of the finest gun makers ever. I took gunsmithing class in Tech College, from W. Ellis Brown, prior to his writing book on same subject, and have done many such conversions successfully. If you read his book, you will understand and appreciate many of these details discussed here. He describes the forces involved in firing double rifle, on action and barrels, in his book. You state that article in DGJ states that "barrel's flex UP and to the side, putting preasure on gusseted area of the water table-standing breach area ?" They do! The right barrel recoils up and to the right, while the left barrel recoils up and to the left. At the same time, in each case, the forces are trying to open the action; many other forces are involved at the same time--again, look at Brown's book.