Sizing Belted Magnums

[Area Man]

I'm new to reloading belted magnums (300 Win Mag) and am on the 2nd or 3rd loading of two batches of cases.

I was reading about Innovative Technologies' web-site about "the case bulge problem". I haven't notice this situation with my brass yet, but was wondering if I am going to need to purchase their Belted Magnum
Collet Resizing Die in order to get much life out of my brass.

Thanks.

 

[CatShooter]

I'm new to reloading belted magnums (300 Win Mag) and am on the 2nd or 3rd loading of two batches of cases.

I was reading about Innovative Technologies' web-site about "the case bulge problem". I haven't notice this situation with my brass yet, but was wondering if I am going to need to purchase their Belted Magnum
Collet Resizing Die in order to get much life out of my brass.

Thanks.

I load for three belted magnums, a 264 WM, a 300 WM, and a 375 H&H, and I have never had Larry's discribed problems in 20 years - nor have any of my friends who shoot belted magnums.

Don't look for problems you don't have.

 

[M-61]

Have a .257 Weatherby since the 70's. Real mix of brass over the years. Never had that problem, and some cases have quite a few trips thru the press for that cartridge. Don't have an accurate count but some have have been reloaded a dozen times I am sure. Not what I call a pleasant cartridge to shoot but over 40 years it has proved to be a fine, flat shooting, long range hunting rifle. Real consumer of powder so it has done a lot of sitting the last year or so.

 

[BoydAllen]

The main thing with belted cases is to ignore the belt and set your FL die for the correct amount of shoulder bump. I use a tight case as a reference. If I have to use once fired, I set the die so that the shoulder is where it was when it came from the chamber. This may sound a bit strange, but as you adjust a die down toward the shell holder, before the shoulder of the die meets the case, the shoulder will actually be moved slightly forward of the fired position, and then as the die is adjusted further down it will make contact with the shoulder, and die adjustments from that point will move the shoulder from that slight extension.

 

[savagedasher]

Belted mag the head space is from the belt. Larry

 

[BoydAllen]

I was not writing about chambering a barrel but reloading, and the most common error in doing that for belted cases is to set the FL die for too much shoulder bump, which causes early case failure. It is really a very simple concept, but shooters still make the mistake of setting their dies to touch shell holders, and not measuring shoulder bump.

 

[CatShooter]

Belted mag the head space is from the belt. Larry

When reloading, the headspace should be from the shoulder, or your cases will have a very short life.

I got that tee shirt about 30 years ago.

 

[savagedasher]

Most belted mags were used for hunting. With that in mind to full length re size you always bum the dies together so the will work in all gun. If it is a custom chamber the usually take the belt out of the head space setting. Larry

 

[CatShooter]

Most belted mags were used for hunting. With that in mind to full length re size you always bum the dies together so the will work in all gun. If it is a custom chamber the usually take the belt out of the head space setting. Larry

It makes no difference whether the gun is used for hunting, or matches - a fired, belted case should be sized so the case headspaces on the shoulder, NOT the belt... or short case life, and head separations will be the result.
This is NOT a theory.

 

[savagedasher]

I guess you have never loaded any for dangerous game. When someone loads for dangerous game you always make the load to Sammy specs the reason being your life depends on it. If someone who is backing you up and he want to barrow more ammunition they must fit in all guns.
Larry

 

[Eddie Harren]

Looks like the 'Immovable Obstacle" has met the "Unstoppable Force". This should be good.

 

[bigedp51]

Rimed and belted cases date back to a time when manufacturing processes and tolerances were very sloppy and to be blunt are out dated.

I would not say this .303 British case was made to SAAMI specifications.

Below is a fired .303 British resting in a Wilson case gauge, the amount the case is sticking above the gauge is how much longer the chamber is than SAAMI specifications.

It doesn't matter when full length resizing if you have a rimmed case, a belted case or a modern standard cartridge case. It is still the head clearance or air space between the rear of the case and the bolt face that lets the case stretch and thin in the base web area.

When any type cartridge case headspaces off the shoulder "YOU" have the ability to control head clearance and case stretching.

Shoulder bump controls headspace, and I never met anyone who lapped the top of his shell holder or ground the bottom off his dies to hunt dangerous game.

I'm just guessing but I think BoydAllen and CatShooter must be as good looking and brilliant as I am.

 

[CatShooter]

I'm just guessing but I think BoydAllen and CatShooter must be as good looking and brilliant as I am.

As brilliant for sure, but not as good looking.

 

[savagedasher]

Great job ever thing you show is correct .Only one problem How do you get the first to work I have a dasher and till I get the first firing it is just a 6mm BR where is the head space then. I can take a 300 HH and shoot it in a 300Wby and fire form it with no modifications. My first statement was to full length size u bump the dies together the true head space is off the belt, rimbed is off the rim and all other are off the shoulder. Larry

 

[BoydAllen]

Larry,
When you bump the die to the shell holder, every time, how many hunting pressure loads do you get from a case ?
Boyd

 

[savagedasher]

All depend on the chamber size.

 

[bigedp51]

I'm new to reloading belted magnums (300 Win Mag) and am on the 2nd or 3rd loading of two batches of cases.

I was reading about Innovative Technologies' web-site about "the case bulge problem". I haven't notice this situation with my brass yet, but was wondering if I am going to need to purchase their Belted Magnum
Collet Resizing Die in order to get much life out of my brass.

Thanks.

The belted "Bulge" can happen with any type case when the case diameter is on the small size and the chamber diameter is on the large size of SAAMI specifications. Therefore not all belted cases or any type case will get the pot belly bulge.

As stated above by our other two good looking and brilliant minds in this forum when full length resizing "MINIMUM" shoulder bump is the key to long case life.

Meaning do not set your dies up per the instructions to make hard contact with the shell holder, because this can push the shoulder of the case back too far. You can adjust you dies by placing a .010 feeler gauge on top of the shell holder with the ram extended and bring the die into contact with the feeler gauge. Then resize a case and see if it fits your chamber, you keep reducing the feeler gauge thickness until the cartridge chambers.

NOTE: If your hunting a Grizzly bear you may feel better if you bump the shoulder back another .002 to .004. BUT I prefer to call in B-52 air strikes on anything that's big enough to eat me.

 

[savagedasher]

Look like none of addressed what was ask does it. Larry

 

[bigedp51]

Great job ever thing you show is correct .Only one problem How do you get the first to work I have a dasher and till I get the first firing it is just a 6mm BR where is the head space then. I can take a 300 HH and shoot it in a 300Wby and fire form it with no modifications. My first statement was to full length size u bump the dies together the true head space is off the belt, rimbed is off the rim and all other are off the shoulder. Larry

You fire form your cases or if you like lots of chamber space you use factory ammunition. In a old American Rifleman one of the editors wanted to hunt Cape Buffalo with a belted magnum and cast bullets. When they got to South Africa the guide made him load and chamber his reloaded ammunition. The very first round when chambered and ejected left the cast lead bullet in the bore and spilled powder all over the action. The guide went back to the land rover got a box of factory ammunition and handed it to the American hunter, and told him your not hunting with reloads while I'm guiding this hunt.

And if you reload the .303 British for the military Enfield rifle you slip a thin rubber o-ring around the case to hold the cartridge against the bolt face and fire form the case.

In a military Enfield rifle at maximum allowable headspace you can have as much as .017 head clearance, and that's a lot of stretch.

.312 pistol bullets with a reduced load for fire forming.

Some of you might remember, the very first question I asked here was how do you people fire form your cases. I'll go back and see if savagedasher replied in that posting. :

 

[jimbires]

I'm new to reloading belted magnums (300 Win Mag) and am on the 2nd or 3rd loading of two batches of cases.

I was reading about Innovative Technologies' web-site about "the case bulge problem". I haven't notice this situation with my brass yet, but was wondering if I am going to need to purchase their Belted Magnum
Collet Resizing Die in order to get much life out of my brass.

Thanks.

I load for three belted magnums, a 264 WM, a 300 WM, and a 375 H&H, and I have never had Larry's discribed problems in 20 years - nor have any of my friends who shoot belted magnums.

Don't look for problems you don't have.

I'll add a 7mm rem mag and a 300 wby mag . I set my die up to bump the shoulder .002 and I forget the belt . I've never seen the need for the collet die Larry sells .