What About a Belt Makes Belted Magnums Trickier to Reload?

Belted Magnums really aren't harder to reload, but they have a few things to watch for. One of the big issues is the brass getting thick at the belt when sizing. There is a specific die to help with this issue if it becomes an issue. Due to the head spacing on the belt, one thing that can be done is just bump the shoulder 2 thou and headspace off the shoulder instead of the belt. This also will help prevent case head separations.

Other than those things, they load like anything else. The big advantage the 7 PRC has over the 7 Mag, is the ability to more easily run the big heavy bullets at a decent velocity.

DMW1116 said:

I was watching a comparison between 7mm PRC and 7mm Magnum and the lack of belt on the PRC was conspicuous. I’ve heard belted magnums are trickier to reload and more frequently have case separation at the belt. Why is that?

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This is only true if you don't set up your dies for the cartridge to head space off the shoulder like normal cartridges.
I don't have case head separations in my 240 or 300. The primer pocket or neck let's go after 5-10 reloads.

DMW1116 said:

I’ve heard belted magnums are trickier to reload and more frequently have case separation at the belt. Why is that?

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Because they headspace on the belt, not the shoulder. So you can shove the shoulder way back, and let the case ‘blow out’ upon firing and repeat until it splits.

That said, this method for setting dies still works with them and eliminates the potential for the problem.

When head clearance/cartridge headspace is set on the shoulder, the area in front of the belt, towards case mouth, becomes unsupported. IMO.

https://www.larrywillis.com/answers.html

If the brass you're using was only ever fired in one rifle and it was your rifle and it will only ever be fired in that one rifle of yours, the belt isn't that big of a deal. If say, for example, your 300 win mag brass was first shot in a military sniper rifle because perhaps there was an ammo panic going on and that was the only brass you could find, you're going to find out that the belt will prevent you from fully resizing some of those cases and so a percentage of your cases simply will not size down to fit your rifle's chamber. You can then spend another $100 on the Larry Willis die which will fix a percentage of those cases but it may be a small percentage of them so of the 100 mil surp 300 win mag cases you bought, you may end up with 50 cases that will chamber in your rifle and so, after spending a bunch of time and money trying to make this brass work, you may come to the conclusion that the belt is completely unnecessary and, worse, can be an inconvenience for the reloader and you may just start looking at the 30/06 or at one of the newer non-belted magnum calibers like 300 RUM.

243winxb said:

When head clearance/cartridge headspace is set on the shoulder, the area in front of the belt, towards case mouth, becomes unsupported. IMO.

https://www.larrywillis.com/answers.html

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Unsupported for how far? 0.002”?

More “insight” that has no real world meaning.

The only thing “tricky” about belted magnums is the belt has more negative attributes than positive.

the old cartridges, like the 375 h&h had no shoulder to speak of and needed the belt for headspace duty.

murf

In my opinion, the trick to loading belted magnums is to forget about the belt and set up your sizing die just like a other bottleneck case that doesn't have a belt. Thats worked well for me.

When loading for my 300 Weatherby years ago I found dangerous case stretching just in front of the belt after just 4 reloads. Adjusting my Weatherby sizing die to not push the shoulder back too far cured this dangerous condition. Get a tool to measure shoulders and adjust your sizer to only push shoulders back about .002” from fired cases from your rifle.

The buckle.

There are no tricks for belted mags, and only one trap - if you want to pretend it’s actually an issue. Load to headspace on the shoulder, and ignore the presence of the belt. If and when case bodies grow large enough to cause chambering issues because sizing dies don’t sufficiently reach the belt, then use a Larry Willis body die. This is not so dissimilar from using a small base die when loading for an autoloader or pump-action rifle - when the base grows too large, fix the problem. Or fix it every loading, just in case - no harm, no foul. This can also happen with NON-belted mags and with standard cartridges well in bolt actions too (I get bolt click in WSM’s regularly, just due to body growth above the shell holder but below the die) - and happens with 9mm’s in the world’s most popular pistol, hence the need for push through bulge buster dies. So it’s not necessarily a belted mag issue, but rather just more frequently bemoaned online for belted mags than others.

I don't currently own anything that uses belted cases. I have in the past and never saw it as a huge issue either way. On the other hand, the belt is a useless artifact on any rifle I own. It had a place on the old school doubles but is just in the way on my bolt actions. It isn't a problem that can't easily be overcome, but a problem I'd rather not deal with. For every cartridge out there with a belt, there is something that does the same thing without a belt and that is the way I prefer to go.

Ru4real said:

Unsupported for how far? 0.002”?

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As much as .015" to as little as .008" on 7mm Rem Mag.

The headspace & cartridge belt need to be both .220" for zero unsupported. Never happens. .

Just how i see it. May be wrong.

DMW1116 said:

Is a similar issue likely with rifle cartridges that head space on the rim?

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On the 30-30 like my Win M94, there can be a lot of slop, loose cartridge in the chamber. Never measured head to data or controled shoulder bump on it. Had no problems sizing with shell holder in contact with RCBS fl die. Maybe just luck?

The 30-30 Thompson Center Contender, different story. Just push the shoulder back so the action closes freely. Working at much higher pressures with this one. No bulging brass seen.

lightman said:

In my opinion, the trick to loading belted magnums is to forget about the belt and set up your sizing die just like a other bottleneck case that doesn't have a belt. Thats worked well for me.

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Yeah, I concur. The first time that I loaded 300 Ultra Mag I screwed the die down too much and it mashed the belt. It wouldn't chamber when I tried to chamber it. Good thing that I caught it before I ruined 20 hard-to-find cases.

Captcurt said:

The first time that I loaded 300 Ultra Mag I screwed the die down too much and it mashed the belt.

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But 300 Ultra Mag doesn’t have a belt…? That’s a major part of the allure.

Too be honest, I've been sizing the 300WinMag (37years) and
375 H&H (24 years) to the shoulder ever since I acquired them.
I have never encountered either loading or pressure issues w/
the brass.


Casting call for anyone who has seen problems.... (?)


.

And I’ve loaded the .338 win mag for 30 years, 7mm Rem mag for over 10. Primer pockets get loose before any other part of the brass fails. My experience anyways.

I always load 7 mag to the shoulder. Getting 10-12 reloads is not a problem.