belted magnum calibers?

[archerynut]

hey gang. always been curious about large powerful chambering's that advertise themselves as "belted magnums"
what is the purpose of the belt? a simple sales gimmick or does it actually help to contain the huge pressure generated during ignition? seems to me that the small amount of material that actually makes up the belt could not accomplish much, but I think I am probably wrong. whats the purpose?

 

[09outlander]

http://en.wikipedia.org/wiki/Belted_magnum

 

[tootall]

Marketing gimmick for the most part, as Wiki suggests.

 

[bettieguitar]

For headspacing.

 

[tootall]

For headspacing.

Yes, for straight-wall rounds like .458 Win Mag or Lott, or very nearly straight like the .375 H&H.
Redundant for shouldered rounds.

 

[Raton57]

Everybody knows it's to make the rifle they are chambered in better then a conventional round. When you can't hit a deer with a 30-06 you go buy a big belted magnum and your sure to hit a deer.

 

[Baribal]

The headspace tolerance is based on pressure level (more pressure = less headpsace allowed) si it makes headspacing much easier and the gauges much cheaper to make, think of the belt like a very big flange.

 

[tiriaq]

I believe that Holland and Holland introduced the belt with their .300 H&H. Long sloping shoulder, likely insufficient for positive headspace control.
May have served a purpose then.
Mostly a marketing gimmick these days, except for the more or less straight cases as mentioned. The new "magnum" rounds are rimless.
Belt has nothing to do with pressure containment.
As far as headspacing goes, it tends to be sloppier with belted magnums than with rimless.

 

[Huntsman]

Many of the belted magnums were wildcats from the existing magnums of the day.