Reloading Belted Magnums

[125 mph]

I've been reading a lot recently about reloading belte magnums like a 300 win mag. This will be the first time I've loaded belted cases. Before I start tooling up, what dies can anyone recommend? How many times can I expect to be able to reload a case?

[opsoff1]

Belted magnums are VERY VERY sensitive to head space. Case head separation is very likey if reloading processes are not followed carefully. The separation occurs right above the belt - which is where the case headspaces - not on the shoulder. If you are shooting once fired brass from YOUR rifle - then you have completed an important step by fire-forming your brass to your chamber. IF you are going to use a full length resizing die - when you go to set it up / adjust it, make SURE your sizing die is set up to headspace off the shoulder - not the belt. I know - it sounds counter intuitive but if you set up the die off the belt, you push the shoulder back waaaay too much. Set it up to set the shoulder back .002 - .003" and that's it. - very very important.
If you are going to use a neck sizer (recommended) then you'll only need to worry about neck tension / neck bushing sizes.

The dies that you should be looking at are a bushing neck die and a body die, plus the obligatory seater.
Separate the body / shoulder sizing from the neck sizing and you'll gain more control over your brass - giving you better ammo and longer case life.
I am personally partial to Redding, but will admit that I loaded my 300 Mag 1000yd gun on Wilson in-line dies. Forster and other make some really good ones as well.

[125 mph]

Thanks for the response, that's very helpful.

If the brass isn't over worked during resizing, is it reasonable to expect 5+ loadings out of a case?

[sinister]

As opsoff has mentioned, belted magnum brass can be tricky (especially if you're firing a factory-chambered barrel).

A "standard" die will bump your shoulders and size your necks.

The Innovative Technologies collet die for belted magnums may or may not help you extend the life of your brass, working like a "Small base die" for lower case (above the belt) dimensions.



A custom-cut sizing die made using the same reamer that chambered your barrel, or another cut using fired cases from your rifle for the dimensions will minimally-size and work your brass -- but will be more expensive.

I am a big fan of annealing to stress-relieve work-hardened case necks and shoulders.

Like any brass, loading to maximums where your pockets loosen quickly or will no longer hold primers makes all the sizing and brass life-extending tricks moot.

Any gas leakage that scars your bolt face is counter-productive.

This resizing die reduces the case diameter "just above" the belt and does not affect any other dimension. It is used after the regular resizing operation. Belted magnum cases now have extremely long life. The primer pockets are "just barely" starting to loosen after 20 firings so I tossed 'em at that point. The necks had barely started to harden, but there are still no signs of cracks. That's a great life span for such expensive brass!

I was so impressed with the end result that I now have a patent pending for this tool. I call it the "Belted Magnum Collet Resizing Die".

This die can be used on any single stage press. Unlike conventional reloading dies, this one threads into the press from the bottom.

Operating Instructions

This collet die is universal and works on all belted magnum cartridges (except 224, 240, 378 and 460 Weatherby). There are no extra collets required. Before each use, be sure that the die and collet are absolutely clean - especially the slots on the collet.

Always use a good high-pressure lubricant on the outside of the collet, and on your shell casing. We strongly recommend using "Imperial Sizing Die Wax" for best results. It is easy to use, it's not sticky and it is very popular with reloaders because it works. Don't use any type of liquid lube.

This collet die should only be used on cartridge cases that have already been resized with a full length (or) neck sizing die. Always headspace on the shoulder, not on the belt. We have had belted magnum cases last more than 20 firings with maximum loads. However, always examine the inside of your cases for signs of brass stretching just above the belt.

The "top" of this die serves as a case width gauge that will identify your oversize cases. The cases that don't fit inside should be resized with the collet die. This avoids overworking the brass and insures a perfect fit in your chamber.

Cases that are fired repeatedly without ever using the collet resizing die can swell beyond recovery. Always check fired cases to see if they will drop freely into the top of the die. Remember that the size of different rifle chambers can vary considerably.

Note that the collet is slightly tapered. The small end is identified by a 45 degree cut on that end. Slide the collet over the case and be sure that it contacts the belt. The small end of the collet must face the mouth of the case.

Remove the locking collar and insert the die (from the bottom) into your press as far as it will go. Adjust the die all the way into the press, as far as it will go. Then replace the locking collar on top of the die. The ram of your press (with shell holder inserted) should have a small clearance under the die - if possible. This setting will allow you to resize the expansion ring on your case (just above the belt) to .510" or as needed.

If resizing seems to require too much pressure, withdraw the case, rotate it, and press it into the die again. Be sure the collet stays seated against the belt. The collet can easily be separated from the case by inverting it, holding it against the shell holder and carefully use your press to push the case out of your collet and into the die.

If you have any questions about the proper use of your belted magnum collet resizing die, contact Larry Willis at Innovative Technologies at it@mpinet.net (or) call at 407-695-2685.

[125 mph]

I have been reading about that die. Will there be any benefit to using that if I'm only neck sizing brass?

I'll be loading once fired brass from a different rifle, so I'll need to full length size the first time but after that I plan to neck size.

What about a factory chamber makes things more difficult?

I could be asking the wrong questions to begin with. My goal is to hit a 20 inch steel target at 1000 yards. Is a belted magnum worth the trouble in that case, or should I be looking at 308s and accepting a little more wind correction?

[sinister]

Factory chambers may be cut with "Generous" (fat or worn) reamers which may allow your brass to swell up to the point you may need to full-length resize every other or third loading/firing to avoid tougher chambering.

Because of the belt you may get tougher chambering, depending on your dies.

A 300 (with a good muzzle brake) will get a heavier, less wind-deflection prone bullet to 1,000 yards with less effort than a 7.62, but with more barrel throat erosion.

[125 mph]

If the rounds were only shot through one rifle after the initial fire forming, would the "generous" chamber size be a non-issue? Not trying to be argumentative at all. Up until now I've only full length re-sized brass, so I'm just making sure I understand how the neck sizing works.

What you say about the 300 makes sense. Seems like 1,000 shooting is a game where you have to pay to play, and the price will either be frustration with the wind, or faster barrel wear. This wouldn't be my only rifle, so I think I'd rather deal with the faster throat erosion.

Thanks for your help, it's much appreciated.

[sinister]

No worries.

Again, it depends on how well your chamber was originally cut and finished. If your brass fits the chamber closely then neck-sizing only is all that's required to hold the bullet.

If the brass swells enough after two or three firings to make it hard to close the bolt (or you get tough extraction) you might want (or need) to full-length size and maybe try the collet sizer.

Even with the finest quality barrels you may only get 1200-1500 "Best precision" firings before you start to notice a decline, then a sharp drop-off.

Chro-moly gives long service with gradual wear. A premium stainless barrel will give excellent to good service, then precision seems to drop off a cliff quickly.