Case necks splitting

[HMFIC]

Touche, but I'm going to say that 300 article is plain wrong; tiniest shoulder is used for headspace (400 Whelen) and even straight wall cartridge can be headspaced without belt - off the mouth e.g. 50 Beowulf.
With that said, and despite of hundreds of internet and published articles, the only logical reason for belt was push type extraction.

True on the Whelen but keep in mind that Whelen cartridges are not a long tapered case and shoulder. While small, they are steep and pronounced so not really comparative to the reasons H&H decided to use the belted design.

Headspacing off the mouth is of course possible but H&H was trying to find a solution to a taper designed case for use in magazine fed rifles. Besides, if the issue was push extraction, then that means it would have only applied to double rifles and hence they would have just made it rimmed, right? Do double rifles even use the belt to extract or do they still use the extraction groove? Hatchers Notebook even says of belted designs that "The rim is not high enough to give a good place for the extractor to take hold, so there is an extractor groove."

Waht is logical to me is that any ease of extraction is just a byproduct of the primary reasons which had everything to do with giving the cartridges a postive method by which to headspace and hold a large tapered cartridge in place without being wedged further forward.

 

[MoBoost]

Headspacing off the mouth is of course possible but H&H was trying to find a solution to a taper designed case for use in magazine fed rifles. Besides, if the issue was push extraction, then that means it would have only applied to double rifles and hence they would have just made it rimmed, right?

The design had to be rimless for better mag feed and belted for push-type extraction - it is nothing more than rim moved a tad forward.

What about rimmed cartridges spaced off the rim you say?

Lets take .303 British. Rimmed cartridge with extreme body taper and basically no shoulder.
With black powder it was indeed headspaced on the rim, and low pressure just wouldn't stretch the brass. Once they went with smokeless, speed and pressures went up - you can still fire once headspaced off the rim, but SMLE chambers are cut very generously. If you were to full length size it and fire again you'd have head separation; so reloading has to be done off the shoulder.

And you know, 375 H&H was low pressure cartridge and can be fired at least once spaced off the belt, but with modern high pressure magnums case head separation is imminent.

 

[HMFIC]

The design had to be rimless for better mag feed and belted for push-type extraction - it is nothing more than rim moved a tad forward.

I agree about the design being rimless for better mag feed, but you're still losing me with push extraction. Do double rifles extract from the groove or the belt? Also, from what I understand, the double rifles may have only been initially offerred in .375 H&H Flanged version (which was introduced at the same time).

What about rimmed cartridges spaced off the rim you say?

Lets take .303 British. Rimmed cartridge with extreme body taper and basically no shoulder.
With black powder it was indeed headspaced on the rim, and low pressure just wouldn't stretch the brass. Once they went with smokeless, speed and pressures went up - you can still fire once headspaced off the rim, but SMLE chambers are cut very generously. If you were to full length size it and fire again you'd have head separation; so reloading has to be done off the shoulder.

I was using rimmed cases as an example of what H&H would have done if their only concern were extraction. The .303 and sloppy SMLE chambers is relevant to this conversation since precision chamber geometry was an issue back in those days and again part of why H&H needed a way to reliably headspace. The .303 had it's rim, H&H wanted something rimless. In the early 1900s it wasn't nearly as easy to get precisely cut chambers as it is today, especially with such a long tapered case.

And you know, 375 H&H was low pressure cartridge and can be fired at least once spaced off the belt, but with modern high pressure magnums case head separation is imminent.

I agree and that is why some even say that full length sizing of belted mags is not ever recommended in reloading. I think we also agree on the fact that reloading to ensure the case shoulder in a .300 Win Mag is fully pressed against the chamber is the only way to go. How to do this reliably and accurately without causing other issues is the trick I guess.

 

[oneof79]

If you guys keep this up I might actually learn something.

 

[HMFIC]

LOL! We might too!

There are really two discussions here: One is the origin and reason for the belt. The other is what the heck you do to make sure you reload both safely and for extended brass life.

 

[MoBoost]

Do double rifles extract from the groove or the belt?

On rimless cartridge you need a spring loaded claw/hook that snaps in the extractor groove and pulls the cartridge out. This system works very well when you have a bolt to attach the hook to. As you can imagine, it's a LOT easier to pull something out with a small hook than to push it out. That's why on break-over action a push bar is used.

The motion of the bar is parallel to the bore axis, and obviously needs something to push on that protrudes from the surface of the cartridge - rim or belt.

Now, they do make doubles in rimless cartridges, extractor bar has a spring loaded hook; they are cool, but are seen as unacceptable liability in dangerous game hunting - last thing you want is fiddling with cartridge stuck in chamber or on the extractor while a freaking man-eater charges you.

 

[HMFIC]

Did you just make my point for extraction not being the direct reason for the belt?

 

[MoBoost]

Belt is there for reliable push-type extraction primarily.

 

[HiredHand]

I thought somebody had already posted this link about case annealing. Its an interesting read. http://www.6mmbr.com/annealing.html

 

[HMFIC]

I thought somebody had already posted this link about case annealing. Its an interesting read. http://www.6mmbr.com/annealing.html

Ya that is a great article, I've read it before.

Belt is there for reliable push-type extraction primarily.

That's only true if they actually offerred double rifles in .375 H&H that extracted on the belt. I don't think they did. In fact, I believe that is why they introduced the .375 Flanged at the same time. I'm betting that they didn't even offer a double rifle in .375 H&H until much later and I think even then it used a pawl type spring loaded extractor that worked off of the extractor groove.

But then again, I could be wrong...

I have an email in to Holland & Holland to get a definitive answer, hopefully they'll reply.

Ps. I fully agree that the only reliable dangerous game method for a double rifle would be rimmed. Just another reason why it's not logical that H&H would attempt to use a belt for extraction in a double rifle.