SAAMI specs

H

Harry Bonar

New member
Sirs:
Cartridge dimensions (saami) on the belt on the 7 mm, mag are: .220 - .008 which means a case belt could be .212
Chamber dimensions are .220 minimum, .227 max. This means your chamber could be .227 max.
Now, if you have a minimum case and a maximum chamber that you have a possible headspace of .015. Unconscionable!
Thia is why I feel the belted magnum case is the most dangerous case in the world. And, if we "headsace" on the shoulder we're opening a possible gap of .015 directly in front of the belt. Unheard of. This set of
circumstances can, at least result in stretched factory cases fired in this condition and, if reloaded and headspaced on the shoulder could cause a spectacular blow-up and possible injury or death to the shooter!
When I did chambering I made a .220 guage and headspaced on that and I do NOT use a no=go guage! It's .220 or nothing, with no play!
Also, the powder chamber on the belted case goes below the belted head belt area!
Many modern developers have deleted the belt on bottleneck cases and

wisely so.
 
Hi, Harry,

IIRC, the heaspace tolerances for rimmed cases are not much different, and .015 is within the elastic limit of the brass. The difference with a belted case is that the angle at the belt is a built in weakness above the solid head, where the rim is part of the solid head. Where a rimmed case will stretch, the sharp angle causes the belted case to break.

As I think I said somewhere, H&H probably thought they were strengthening the case and in any event never intended those cases to be reloaded, something the British at that time didn't do. I agree that the belted round should go away; it is an illusion of strength that doesn't exist. Still, illusions die hard, so I suspect the belted case will be around a while.

Jim
 
What I thought and did.Never push the limits.

I have always marked brass to the rifle and marked it to insert it the same way every time.I only trimmed & neck size when I reloaded.I then tried each completed cartridge in the individual piece.I even marked my brass to the individual revolver cylinders that they were fired in.300 Weatherby and 7 mm Remington mag were my only mags in rifles and 44 in revolver.I also loaded to lower pressures with the powders that allowed such.My brass seemed to last far longer that most claimed for theirs.With the variety of firearms I had I never felt the need to push one.I just selected the correct one.The only reason for my purchase of the Magnums were to have rifles that could be used for prairie dogs to Brown Bear in a pinch with reloads.I never got in that situation.I am in the belief that I was following the safest and best course concerning bolts,chambers,brass and head space.Was I in your opinions?

Head space is always there,whether good or bad.I see no need to push to the limit whatever you have.It just don't make sense to me.I do know that some military rifles,the British Enfields for example are deliberately made with clearance often up to the max to operate in the blood,mud and the filth found under battle field conditions.Now their brass was not designed to be reloaded and was most often stronger made.

I have also found that the best accuracy was most often found at the lower velocities and even when it was not,I could find a acceptable load at the lower velocities.

What do you think of my opinion and ways.I am always looking to better myself and my opinions.

Thanks.I AIN'T DEAD AND I AIN'T QUITTING.alfred
 
Any way you can minimize case stretching and other problems is OK by me. The problem is that most folks are basically dependent on the rifles they buy and often on the ammo they buy. They don't have the option of custom chambering the rifle. Too bad, especially on the belted magnums; have you priced a cartridge like the .416 Remington Mag lately? I think Cabelas has them at something like $175 for 20!!!! Of course if you can affort to hunt in Africa, that is chump change.

As to reloading, I notice a definite drop in interest; I don't know if people just have more money (that might change) or they don't have the time to bother. A nearby gun shop had a used reloading press for sale last week, and several of the younger customers had no idea what it was!

Jim
 
H&H probably thought they were strengthening the case
Click to expand...
Actually, H&H thought they were giving that loooooong, tapered cartridge something to headspace on. THe 375 H&H Flanged uses a rimmed case, but the other dimensions are virtually identical to the belted case. Due to issues feeding rimmed cartridges out of staggered box magazines, the belt gave them the same functionality without the rimmed case issues. Since the belted case was performing double duty (double rifles AND bolt action rifles), it needed to have some sort of headspacing provision.

Given that the 375 H&H cartridges (both flanged and belted) operate at fairly modest pressures (by today's standards), and the practice of not loading cartridged to high pressures to avoid cases sticking in the chambers of dangerous game rifles, I doubt that the H&H designers felt they were strengthening the cases by adding the belt.
 
Since the belted case was performing double duty (double rifles AND bolt action rifles), it needed to have some sort of headspacing provision.
Click to expand...

Nope.
H&H very sensibly made bolt action rifles for the .375 belted and double rifles for the .375 flanged (rimmed).
Use of the double (and single) rifle declined to almost nothing, so the flanged cartridges were dropped. So when the occasional order for a double came in, it had to be set up for the belted with the same sort of extractor used for plain rimless. It does not engage the belt, that would require the chamber wall to be cut away too much.
 
headspace

Hey Guys,
Im typing on a French keyboard laptop I do not really know what Im doing
I agree with you guys = ammo is going through the roof and I have always handloaded - I cannot find the period on this thing - I do not like the French anyway- I like the 416 Taylor - built three of them for myself - I hunt elephant, cape buffalo, and leopard in my back yard here in ohio , it really works great on rhino too,
Harry B,
 
Harry.Save some money and weight.

Harry.I am going to quote a man who claimed his family was in the business and went back in it to the old Boer Trekkers.More of these animals were killed with the old military surplus rifles than all of the "White hunter guns" put together.Mausers and Enfields were modern guns.He came up on tales of the old huge bore muzzle loaders.The Great White Hunter movies that we were brought up on were popular there as comical.

The standard way was to gut shoot Elephant and Rhino,later look for the Vultures,then chop out the tusk or horn for sale.A shot in the eye with a small bore also normally dropped them due to infection later.It seems as if poachers had learned to kill them with a treated pellet from a air gun in the eye!When the legs and feet got to be valuable for umbrella stands they started trying to drop them to remove them to preserve while fresh.Same with Cape Buffalo as they were killed because of crop and fencing damage.Leopard and Lion was the most dangerous simply because you wanted no damage to a valuable pelt.Most of the animals were not killed as game.They were killed off simply as self presentation to defend their lives,homes,live stock and crops.Even the monkeys destroyed crops,stole and ate chickens and eggs!The Ak-47 & SKS was the gun most used to take all game including Elephant,Rhino,Gorilla,Lion,Buffalo,Boer(Yes Boer),Priest,Nuns and all other tribal enemies when he left".

Save your money and the weight of the "Big White Hunter guns".You can hunt them all "correctly" with the 7x57,303 and the 7.92x57J or 8x57 cartridges.I often sit in my back yard and poacher hunt them all with my Chinese Air Gun just as Some Africans do!I can not imagine the courage or else the size of the tree for a stand it takes to do this.I also can not imagine one of them being able to run with the anatomy that they would have to have to do this.

I AIN'T DEAD AND I AIN'T QUITTING.alfred
 
Alfred,

Sir,
I could not agree more = we, in this country are greatly, grosslyhothot, overpowered in this country abd I agree with you, If we lived in the Cretaceous period we could do in every dinosaur on the planet with a properly placed shot from a 30=30,
Harry B,
 
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