It's once fired Norma .338 win mag brass, and sized in a new Forster full length sizing die. Cases are lubed wit Imperial Sizing Wax.

The ring of brass ahead of the belt is actually fairly substantial, and looks like it could offset the headspacing, but I haven't noticed any different in chambering or accuracy.

What is causing it, and do I need to get rid of the excess brass?
Is there anything I can do to remedy it?

Could it be an oversized chamber? Undersize die? Oversize brass?

G'day,
Before you size another case, take a fired case and measure just above the belt on the expansion line. It should measure no more than .512", if it does, then either the cartridge isn't being supported correctly in your chamber, or the chamber is oversize, or your die is adjusted too far down on the case and is oversizing the brass.
We need that dimension above the belt to determine the cause of your problem.

Cheers.

I opened this thread wondering what the problem was.

Now I see it is belted magnum, I think I know what it is.

An awful lot of manufacturers cut their chambers far too big for magnums, so after firing,a sort of new belt is formed just ahead of the original belt.

When we cut a magnum chamber - all our reamers are custom made, top minimum specs - I run the reamer in just far enough for a new case for the bolt to close on.

No more.

The bolt does not close on a GO gage.

But, we have chambered so many rifles, and had never encountered a single problem of them no accepting factory ammo.

Cheers, I'll measure one this afternoon. Unfortunately all the fired cases I have left have been sized, but I should be able to check the spec.

The ie is adjusted so that is only just kisses the shellholder, so it can't be that...

I will add that for no earson I can understand, one or two cases, in 50, did not have this problem.

Saeed, when the belt you are talking about is formed due to an oversize chamber, is it visible?

You will get many opinions here for sure.

I have a .458 WM that does this on brass that was reloaded for the 2nd or 3rd time. I bought a collet die called the "belted magnum die" and it solved my problem. The maker gives an explanation but it gets criticized by many here much more learned than I on reloading.

I use it on my .458 WM brass as the very first stage in reloading it. All my other dies stay set exactly the same...I just first run the brass through the collet die.

Yes, you should measure a fired case just ahead of the belt BEFORE resizing. However, you should not expect .512". I have a Tikka in 338WM that produces .516". The chamber is obviously cut large. when in the US I neck sized for consistency. However, if shipping rounds to Africa I always use new brass, for a different consistency. It appears that the 'large chamber' rifle was using about 1.5 grains more powder (Rel-17) for loads equivalent to a tight chambered rifle.

Another point to test would be with a couple of brands of factory loads. Fire a couple of rounds and measure. do they measure the same?

finally, do the same test with cartridges loaded just below 'book max'.

If so, it would appear that the chamber is cut too large.

Regardless of how oversized your chamber may be (and this is exceedingly common), your die should not shave brass. The shaving is likely caused by an inadequate bevel on the die opening (bottom of the die). I say "likely" because it could be caused by a misalignment of the case and the die due to an out-of-round or otherwise misaligned shellholder -- but that would show up as shaving on only one side. If the brass is shaved all around then its cause is the too-sharp edge of the die opening.

The remedy is to bevel the die opening. Since the die is made of very hard material this is easier said than done, but it's not rocket science and can be accomplished with the right kind of ball or conical stone in a power tool.

You say you have the die set to "kiss" the shellholder. Why do you think this is the right setting for your (likely oversized) chamber? The die should be set so that it "kisses" the shoulder of the case. This may or may not have some close relationship to the relative position of the bottom of the die and the shellholder.

Sometimes we fail to take into account that a "standard" FL sizing die has to reduce brass to so that all dimensions are equal to or less than the minimum chamber dimensions. And chambers are cut so that they are larger than those dimensions. Manufacturers often "fudge" by making dies even smaller and chambers even larger. When you run across a minimum die and a maximum (or larger) chamber, then you've got a problem.

So, some FL dies are simply incompatible with some chambers. If a die is considerably narrower in diameter just below the shoulder than the chamber, then the shoulder will be pushed forward before it comes in contact with the corresponding shoulder of the die. This situation will require you to "full length" size the cartridge even when you would otherwise prefer to size only its neck and slightly bump back the shoulder. If such a situation exists (usually due to an oversized chamber) then your best solution is to have a custom sizing die cut from the measured dimensions of your fired cases.

quote:

Originally posted by EXPRESS:
Cheers, I'll measure one this afternoon. Unfortunately all the fired cases I have left have been sized, but I should be able to check the spec.

The ie is adjusted so that is only just kisses the shellholder, so it can't be that...

I will add that for no earson I can understand, one or two cases, in 50, did not have this problem.

Saeed, when the belt you are talking about is formed due to an oversize chamber, is it visible?

We have had a 257 Weatherby Magnum, custom made by Francotte of Belgium, that formed a visible belt after repeated firings and loading.

That brass cold never be used in any other rifle.

It ain't your brass, nor your chamber; it is your die; chamfer the entry of it and your shaving will go away.
True, SAAMI specs allow a huge amount of slop in the tolerances and there is nothing you can do about it with a factory chamber and brass. Make it headspace on the shoulder is the best you can do to prolong brass life.

As has been said, it is your die that is at fault. It will have a recess at it's mouth for the case belt and the edge of that recess inside the die, corresponding to where the front edge of the case belt will stop at is very obviously sharp as it is shaving virtually to that belt front edge. Failing having a tapered stone you could use a suitable sized socket from a socket set, the type that are tapered from the nose back, put a wrap of wet and dry sandpaper on it and spin enough to take off that sharp edge in the die.

Bet that will cure your issue.

In my case...if it were the die...why does it only happen with some cases (usually older cases) and never with once fired brass? Usually takes 3-5 reloadings for it to start. The collet die eliminates it. It always happens just above the belt and looks like the OP's pics. Now I am sure that you could radius the die mouth to make it stop...but is that what we want??? My .458 WM does develop a bulge in the brass above the belt with several reloadings to the point that my FL die will shave off brass. The collet die solves the issue.

A collet die will help solve this problem.

It is not the die mouth that needs to be radiused on a die for a belted case, most dies already have a smooth radiused mouth, it is just taking the edge off the belt recess inside the die itself that is needed.

This will not alter the dies ability to size the head of the case right up to the belt, it will just stop it shaving the bulge instead of swaging it.

I resized belted 7x61 cases for years, some of them many times reloaded and loaded right up to full factory pressures which for the Norma ammo was high - genuine 3000fps with 160gr bullets in cases that are smaller in capacity than 7mmRM. I never had issues with FL resizing in Lyman dies.

Yes, I should have said that; it is not the actual die mouth; it is the "inner" mouth; which does the actual sizing, is too sharp. Spin it in a lathe with some emory paper on a stick.

I measured some fired cases, and ahead of the belt, the case measured .5177 so there is some swelling there, but it is marginal.

The die does seem to have a fairly sharp lip, but it is hard to tell because there needs to be a definite step for the belt.

So it looks like a combination of factors might come in to play, a collet die would definately be a good addition, but I will be curious to see if these cases continue to do this on their second firing. If so, then I will definately get the collet die ASAP.

I try to have the die set up to bump the shoulder, but at the moment I don't have a tool to measure the set back. I will turn one on the weekend. For the moment I use a fairly empirical method, where I lower the die until I see contact on the shoulder of the die, by putting some dry lube on just the top of the shoulder. You could probably use talc or better yet candle smoke to blacken the case and see when you are getting a bump on the shoulder.

I tried chambering the fired cases, and they chamber just fine, but in a Blaser rifle, it is hard for me to gauge the resistance the bolt has to close.

We shall see.

Actually, .5177" is definitely oversize and not marginal. More typical would be .513".

There is nothing inherently bad about an oversize chamber, except that the brass should not be used in other rifles with serious full-length sizing. And factory ammunition will produce lower than optimal velocity for your rifle.

Do you have access to a chronograph? With an oversize chamber I would expect your loads to be under-velocity. The capacity volume of your rifle is essentially a bit bigger than normal, which means less pressure and less resulting velocity for a given load. How much different? Maybe a grain or two. In other words, the pressures that a given load is supposed to reach may need an extra grain of two of that very powder in order to reach the anticipated pressure levels.

I didn't realise that just .001" is all I should expect in expansion.
I do, or rather did have a chronograph whack I ways use for load development and target shooting to keep track of my ammos' behavior. But I shot it during the first session of development with this rifle, so no MV info. One thing you mention that I did notice is that at the published maximums and 1% above, there were still no discernible sign sod excessive pressure.
Industry ordered another chrono today, and have some more trying to do.

Lane has it nailed. Belted magnums go out of spec just above the belt. The collet die takes care of this. Don't try to over think this and don't alter your die. Velocity will not be affected as the brass seals the chamber upon ignition. If you don't have dark powder stains on your necks then the chamber is sealing fine.
Get a collet die and your troubles will be gone and you will get many more loadings out of your brass.

quote:

Velocity will not be affected as the brass seals the chamber upon ignition.

It's not a question of sealing, it's a matter of increased volume. Not a whole lot, but enough to need a grain or two of powder for the larger volume.

Here are the numbers; they scare most guys who don't know just how sloppy their brass and chambers are allowed to be.
Don't fret.
Brass spec is .5126 in front of the belt, with a -.008 tolerance. so brass can be .5046 and still be within specification.
Chamber spec is .5136, +.002, so chambers can be .5156 OD,
So with a max chamber and min brass, you can have Eleven thousandths .011, of clearance.
And die makers have to operate within these specs and hope they get it right; it is amazing that they work as well as they do.
So, finding a combo of brass, dies, and chamber that scrapes the brass a bit, is nothing. Just polish the inside mouth.
Collet dies? I don't use them although some like them.

dpcd has it right.

Any combination of oversized chamber and undersized die, with a sharp lip on the die, will shave brass. This is true whether the rim is smaller than the case body (rebated), the same size as the case body (rimless), or larger than the case body (belted and rimmed).

Having a belt on the case is of no effect in this regard, other than the fact that manufacturers habitually use oversized reamers with belted calibers simply because they reason that the cartridge will still headspace on the belt, so why not? As a result of this manufacturing practice, compounded by the typical practice of loading belted "magnums" to higher pressures than "non-magnum" cartridges, the problem of bulges near the base of fired brass shows up somewhat more often in belted calibers. This has led to the belief that belted cases somehow are subject to bulging that rimless cases are not. While it is true statistically that the problem shows up more often in belted cases, it has nothing to do with the belt -- and the cure is identical to what you would do regarding a non-belted case: Chamfer the offended sharp edge of the die.

Sometimes the combination of oversized chamber, slightly soft brass, and sufficient pressure conspire to leave a case which, after firing (perhaps after several firings), will not easily re-enter the chamber. Conventional dies are normally not designed to resize the bottom 3/8" or so of the case (the RCBS "small base" sizing dies are the exception). So, someone invented a collet die which will squeeze the bottom portion of a belted case back down within tolerances. That's one way to address the combination of problems I describe. However, unless and until your brass is so bulged that it won't re-enter the chamber, there is no need for such a tool.

quote:

Originally posted by ledvm:
In my case...if it were the die...why does it only happen with some cases (usually older cases) and never with once fired brass? Usually takes 3-5 reloadings for it to start. . . . My .458 WM does develop a bulge in the brass above the belt with several reloadings to the point that my FL die will shave off brass. . .

Lane,

You've described perfectly the result of an oversized chamber and an undersized die (at least relative to one another -- doesn't matter which.) With each successive firing the "pressure ring", which is the point on the brass case that the wall becomes thin enough that it can no longer resist the pressure and is pushed against the chamber wall, will grow a little larger, and move a little closer to the case head. This happens until you reach the point that the die shaves the lower body of the case just above the rim. Even if the rim weren't there, the body would still be shaved.

You say that it happens with some cases and not others (and never on the first firing). This is because cases vary from brand to brand and lot to lot within a brand in their head thickness, and especially in their head hardness. With a batch of cases which have a bit softer or thinner heads, then your problem will show up quicker. Softer brass also has less springback, thus leaving the cases too tight to readily re-enter the chamber.

Using the collet die does the same thing that a proper conventional small base die would do, but I suspect that the collet die does it better and with less effort. However, when cases are soft enough to bulge to the point that they don't want to re-enter the chamber, you're pushing the envelope by work-hardening the case wall with the collet procedure and potentially inviting a case head separation.

Many shooters don't realize that the rear 1/4 inch or more of a case is totally unsupported by the chamber walls. In fact, a portion of the case head (rear wall) is necessarily exposed in the gap between the bolt face and the chamber (even with a rebated bolt face). The chamber support only starts forward of the pressure ring. That's why the case head has to be thick at this point, and why a blown case head at this point is so dangerous.

I think it is an unwise combination to have a rifle with a large chamber, shoot loads which generate enough pressure to continue to expand the case head, then resize the case head to compensate for this. This is a recipe for a blown case wall or head separation.

Hi Stonecreek,
I agree the old 1957 M 70 has a large chamber.

As you know we have discussed this several times before.

I have loaded for and shot this rifle a lot and just load one load for it that I use in Africa so I like my practice loads just like my hunting loads so I do them all the same.

I only load new brass for Africa trips and often times it stays in Africa.

So I have brass now that I have loaded 10 times or more for practice. I inspect the brass closely and use a feeler wire to feel for a ring indicating impending case seperation.

Thus far I have not found/had any brass problems from using the collet die. As long as I use it routinely from the get go with new brass...the brass never seems to get even a hint of a bulge as can be measured by the gauge with the die. So I don't think I am excessively work hardening the brass by using it the way I do...at least anymore than routine FL resizing would be doing. The die seems to be a good tool for this application in this .458. I have several other belted mags that don't express this issue so I don't use the extra step with them.

Well I smoothed the dies off with a diamond burr and some emory paper, and set it up with a fired case to get a should bump using carbon from a candle to determine when I am getting about 50% of the shoulder pushed back, but it still seems to shave, to push, some brass into the new belt that the shaving caused.
I suppose I'm going to have to get a collet die, but what harm is this actually doing to the brass?

You have a very large chamber, or a small base die; I would hone the die out a bit so you don't have to work the brass so much. Or try a different brand of dies but that might not be any different. Spin the die in a lathe with some emory paper on a stick; that will do it. A chamber cast would be helpful to get what your dimensions really are.
What harm are you doing to the brass? None.

You cannot shave a metal unless you have a sharp edge. Even small base dies do not shave the cases they are sizing they just swage. It could be possible to shave brass on a case if there was not enough lube i.e. grippy enough to 'strip' brass from the surface but in all my reloading I have never seen this happen.

We never used to have collet dies and yet reloaders have been loading belted cases ever since they were invented in normal FL dies.

As dpcd points out you obviously have an oversized chamber and need to chamfer the leading edge of the belt recess in your die some more, not just a pure angled chamfer but rounded as the mouth of the die itself will be.

Are you doing any harm by shaving the brass? Well if you keep shaving brass you will be thinning the area just ahead of the web which is where case head seperation eventually occurs. You want to keep all the metal you can in this area.

EXPRESS,

It might be easier to buy a new set of dies. They are not that spendy and it very well might fix your problem with no hassle at all.

Mark

Or...just buy a collet die as I would bet every dollar I have in my pocket that it will solve the problem.

What I dont' understand about the collet dies is that they are supposed to be used after FL sizing, so how will that stop the FL die from shaivng?

I will get more aggressive with smoothing the dies today, and see if it makes any difference, though when I said it is still shaving brass off, it could be pushing the accumulated brass up, moving or ploughing it, rather than outright shaving.

The other thing is the the bulge, as evident in the photo, is not visible, nor is there any perceivable step when measuring with the calipers.
Maybe it's thick brass?

This, to me is getting weird, I reload for 7mm rem mag .300win mag, .300wby .375H&H .458win .458 Lott .416 rem - a total of 7 belted mag calibers, the .375 .458 ammo all going through 5 different rifles, all with no problems.

I'm starting to suspect that it might be the die that is too tight at the base, and that the brass and chamber are fine...

quote:

Originally posted by EXPRESS:
This, to me is getting weird, I reload for 7mm rem mag .300win mag, .300wby .375H&H .458win .458 Lott .416 rem - a total of 7 belted mag calibers, the .375 .458 ammo all going through 5 different rifles, all with no problems.

I'm starting to suspect that it might be the die that is too tight at the base, and that the brass and chamber are fine...

As I previously stated, this is NOT a die problem.
If your cases measure above .513", no matter what the specs for the chamber and brass are said to be by SAAMI, then your chamber is NOT fully supporting the case head as it should.
I have seen this compounded by rifle design, such as large coned breech designs, and the fact that some brass brands are THIN above the belt, both Winchester and Norma brass are thinner than other manufacturers, but Norma is the worst and compounded by being relatively soft compared to other brands.
The collet die may just be the fix, but do not expect long case life. I am not a proponent of that product, in fact I believe it causes more problems than it addresses.
But, if it fixes your issue that another die doesn't, then so be it.

Cheers.

You are right, it is not the die. I rana case through my .458 Lott die without a stem in it and it came out with the same, if not worse result.

quote:

Originally posted by dpcd:
Brass spec is .5126 in front of the belt, with a -.008 tolerance. so brass can be .5046 and still be within specification.
Chamber spec is .5136, +.002, so chambers can be .5156 OD,
So with a max chamber and min brass, you can have Eleven thousandths .011, of clearance.

If I have a max size chamber, then wouldn't the best solution actually be a custom sizing die? I once ordered some custom wildcat dies that were not all that expensive, and a collet die still costs $100 - $180 by the time it gets here to me...

quote:

Originally posted by EXPRESS:
What I dont' understand about the collet dies is that they are supposed to be used after FL sizing, so how will that stop the FL die from shaivng?

I will get more aggressive with smoothing the dies today, and see if it makes any difference, though when I said it is still shaving brass off, it could be pushing the accumulated brass up, moving or ploughing it, rather than outright shaving.

The other thing is the the bulge, as evident in the photo, is not visible, nor is there any perceivable step when measuring with the calipers.
Maybe it's thick brass?

You are correct...for this problem...you have to use the collet die as the first stage in the process. See my statements above.

A chamber cast will tell you if you have a big chamber, which you do, so yes, a larger, custom die made for that chamber would be the best solution. Assuming you do not want to set the barrel back and re-chamber with a smaller reamer. You can make the custom die by polishing yours out, in a lathe. Or with a drill, a stick, and emory cloth/paper. If you were here, I would fix it for you.

Express: The fact that you load for seven other belted calibers with no problem pretty well illustrates that the problem with your .338 is not caused by the fact that it uses a belted case, thus dispelling a popular myth.

dpcd has outlined your options quite well (and in addition, the collet die is yet another option since it is, in effect, a die with a variable dimension at the base of the case which can be adjusted to fit your chamber).

However, another possible option is to change brands of cases. As has been mentioned, Norma cases have historically been made with somewhat softer heads than most other makes of brass. This softness exacerbates the problem with the oversized chamber since the soft brass both expands more than harder brass and springs back less. It is entirely possible that if you changed to brass with a harder head that you might find little or not case bulging, or at least that the pressure ring would show up further up the taper of the case where it would not create such a problem. I know that obtaining components in Italy can be a problem, so a change to other brass might be impossible. However, if you have some brass other than Norma for perhaps your .300 Winchester, you might reform a few cases to .338 to see if you find that brass behaves differently.

Yes, Stone is absolutely right; stop using the Norma brass.
Just for info, and not for this issue; back in the iron age when we could not get brass for everything like we can now, we used to wrap masking tape around the bases of cases to keep them from swelling; now, this was for old double rifles operating at relatively low pressures, and for BP pressures.

Thanks for all the answers guys, I was thinking of trying to resize some Lapua .300 win mag brass I have,
to see if is is any better. Unfortunately it is hard to get certain components here, and since Lapua stopped producing belted cases that limited the options for quality brass. I got this batch of Norma from the U.S., because .338 win mag is quite a rare caliber here, and it was the best quality brass I could find.
Who else makes good quality brass, maybe Nosler or Hornady? I found that the Norma brass, at least in consistency is as good as Lapua, albeit softer. While here, the Remington and Winchester brass that makes its way over is rubbish, if you start sorting and culling for accuracy, your pile very quickly diminishes.
Before I it $250 into a custom die I should try some other brass...

May I suggest you buy a Redding body die and see if that fixes your problem. I know Blaser rifles are tricky to load for due to the collet style lock up system, but you can overcome this by buying an RCBS Precision Mic in 338 that will allow you to measure your fired cases, although it's said to be tight toleranced, I believe there is still some spring in this type of action.
When you have the barrel off, how much does a sized case wiggle in the chamber?
I hate seeing a fellow Aussie in trouble, if I can assist with any parts/dies/ordering etc, please let me know, I would be glad to help.

Cheers.

If I get the collet die, and bore out the bottom of the FL die, then set the FL up to bump the shoulder, wouldn't the end result be the same as a custom die?
that is assuming I can set how much the collet resized.