Someone who knows, can you please tell me why cases for magnum bullets are belted?

Holland and holland started the belted case for headspace... Hence why modern cases based off the original 300 HH case ie: 300 win, 300 wby.. Have a belt.. In these designs it basically serves no purpose.. But it's on the parent case it was designed off of..

Exactly. Instead of head spacing on the shoulder (like most bottle-necked rifle rounds do), they head space on the belt. Even your 450 Marlin, and other similar rounds are belted.

On the .450 Marlin, it is belted so it can't be accidentally loaded into a .444 Marlin.

As I understand the story...H&H wanted to be super sure that their new longer super skinny, no shoulders to head space off of case 375 African round would/could be extracted in their double rifles weak extraction shotgun styled setup no matter what the environmental conditions were, and created the belt to headspace off of and extract off of too as insurance for the expected African heat and super dusty/dirty conditions when facing bite back man eaters.

Remember back in those days coming out of the black powder era, all smokeless Gun Powders were a single base extrusion of chemically impregnated cellulose in very long spaghetti like strings...hence the longer the case, the more powder could be packed into it. Credit the Champaigne Industry for the larger sized bottles being called "Magnum"s. Monkey See Monkey Do ...and no patent infringements to worry about.

Today with the advances in chopped single & double base cellulose, ball, or flaked powders the belt is unecessary and simply an affectation - like fins on a '57 Chevy made 'em go faster! for the Gun & Ammo Co's marketing dept's advertising campaigns right after WW II...including the best known today with Roy Weatherby's useage of the H&H belted design to imply this was a hairy knuckled "MAGNUM" and not just another pre WW ONE makeover like all the 30 cal US Springfields or ??x57 Mausers variants were. Several other British & German/Austrian proprietary houses had some new designs but none survive I'm aware of today that have any volume of guns or ammo sold impact....except the pre 30'06 design of Herr Otto Bock in Berlin in 1905 of the 9.3x62 Mauser that was big & powerful enough to be usued to control maurading crop damaging critters like elephants, rhino, hippo & cape buffalo, and fit into a standard '98 Mauser reciever and was able to be bought at reasonable prices without having to go thru the Brit Gun Houses as the Boer War was breaking out....between the German/Dutch colonist farmers and the British Empire taking over all of the southern portion of the African Continent south of thre Equator.

Even the Short Fats Mangler basic designs of today are nothing but shortened makeovers from earlier stuff like the Brit 404 Jeffery.

IMO the best new stuff to come out in the last 20-30 years is the new more efficient powders and boolit designs...Just Sayin' & YMMV.
Ron

Thanks for some good history Ron.
Did the .300 H&H come out before the .375 H&H?

jeh...dunno which was 1st...or maybe close enough to be called "about the same time".

When we were in Finland on the SAKO plant tour & moose hunt in October '84, a member of our guest group was an American gentleman named Howard French, the Editor of Guns & Ammo Magazine. During one of the tours the honored guests and non Management people like myself and the other Stoeger rep from SLC, Bill Haislip, took a tour to a private family owned gun museum. This family had collected mebbe 7-10,000++ guns over 4 generations from Europe to Siberia while working on the Trans Siberian Railroad, all housed on their property in unique buildings that are very very camoflaged.

Howard, come to find out was far far more than just another gun shill for a magazine, was a student of British Military history as well. I stuck to his side like a shadow to glom every last tidbit of his vast knowledge and wisdom at every opportunity. We looked at Brit militaria from blunderbuss's to current campaign weapons among stuff from all over the world in every possible configuration....heavily bejewled Arab black powder guns to an Armalite test model of the AR 15 in the white with stenciled control numbers on the handmade fibeglass stock. Howard would go thru a section and point out this or that rifle or pistol had been at the battle of something in 1839 in the Crimea or in France, Turkey, the Kyhber Pass or Shanghai and how many were killed on each side, who led the troops and all the minutia a true history buff delights in. Weapons from the RussoBritish?? War that the famous poem the "Charge of the Light Brigade" were there....with battle damage still evident. He especially was strong on African History and with any rifle connected in any way to the Dark Continent Howard could give you a dissertation on it's history by Unit, Battalion & Regiment.

Google "Howard French" and see if you can find anything he's written about the History of Holland & Holland firearms. OBTW he also became an accomplished author of childrens books, after he left the firearms industry. Howard retired shortly after the SAKO trip to live out his days in Chelsea England with his delightful and gracious English wife we had missed on our trip to Finland. What a great and rare treat to spend 10 days with Howard in our Hunting Party.

Sometime I'll tell ya'll the story of another of our special guests the Russians were still looking for in 1984 after his world famous exploits of personal courage in Budapest in the Hungarian Spring Uprising of 1956. The local Finns we were around would stand in a salute and applaud his presence whenever they found out who he was. We had had a Finnish Border Guard Captain as an armed escort as a member of the hunting party...and DA me I never knew why until the end of the trip at the Final Luncheon when it was explained to all of us after the gentleman had had another standing ovation from the entire restuarant, patrons and staff.
Cheers
Ron

wow very interesting stuff.

Magnum has nothing to do with the belt but the size of the case. It is a carry over from the wine industry, a magnum was a larger bottle of wine.

There are lots of "magnum" named cartridges that are not belted.

357, 41, 44 Remington Magnums, the Remington Ultra and RSAUM series are not belted as well as several others.

Magnum has nothing to do with the belt at all. Just another waying of saying "bigger". It's a sales gimmick.

The only a very few cartridges I can think of that actually need that belt. They are the 450 Marlin, 458 Winchester, 458 Lott and 470 Capstick. There would be a very few more.

Belted cases are for the safety of those who don't know why they are belted.

Case in point - I shoot a lot of .300 RUM and there is no PITA belt to deal with.