BONANZA It is true that modern steel, used in firearms of today, is much better than the, mostly IRON, of the old days! However, the breaktop double rifle is still 18th century technology, and are definently not suited to high pressures. There is a sound reason the 375H&H Flanged was loaded to lower pressures, than the belted rimless round. That reason was, the rimless was made for bolt rifles, and the flanged was made for doubles, and break-top singleshots. Addtionally, the tiny pawls used in double rifles for use with belted rimless rounds, are problematic, when paired with African talcum powder dust, or sticky cases. You may use your Merkel for years without problem, but pray when a problem occures, it is not in the face of a big buff! Things that you see smoking, are usually caused by fire someplace, and this one has been smoking for about 90 years, and the 375 H&H, in doubles, is the cause of the fire, that long ago! However, the chambering of this type cartridge was only started again in the late fifties, when the old NE rounds became hard to find. It wasn't a good idea, but they had no choice, if the wanted a big bore double, the 458 Win Mag, and the 375 H&H, both belted, and high pressure, were the only choice. Most of the 458s have been re-chambered to 450NE, or 450No2NE, and re-regulated, but the 375 H&H has to be re-barreled, so those can still be found, but that doesn't make either of these rounds a very good choice in a double! I wish this were not true, because the 375 H&H is one of my all time favorite rounds, so you can beleive if I thougt it was a prudent idea, I would have one!