Weatherby Headspace Confusion

B

Bucksnort1

New member
Until yesterday, I thought headspace on Weatherby belted cases (as well as other belted calibers), is set by the belt; however, after watching Larry Willis' (Innovative Technologies) video I received when I bought his belted case resizing die, he says to set the re-sizing/de-capping die, after the first firing, so the case sets headspace off the shoulder and not the belt. Later, I read the same thing in another publication.

Without getting several encyclopedias of explanation, will someone explain how I set my de-capping die to do this?

Or, should I not be concerned about headspace at the shoulder?
 
Ideally, the head space of the belt and the shoulder are the same. But chambers rarely are "ideal". The big issue is if the belt is too far into the chamber, in that case a belt cartridge will set back a bit on first firing, and the distance between shoulder and belt will increase. If you now head space your reloads on the belt, you are setting back the shoulder each time, weakening that area and leading to premature case loss, while the excess head space behind the belt will stretch the web of the case, inviting dangerous blow-outs.
That's why the recommendation is that you only size until you touch the shoulder, not until you hit hard on the belt. You can set that if you figure out the distance needed and either shim the die or dial it in to the correct distance with a feeler gauge.
 
Pogybait, it is either or, not both. I have one rifle that comes very close to hitting at the belt and the shoulder at the same time. That one rifle shoots one hole groups.

The problem from the big inning has to do with reloaders that can not determine the length of the chamber from the shoulder of the chamber to the bolt face. Then comes fire formers and those that insist on returning the case to minimum length/full length sized. And the concept of the 'leaver policy'. Either learn to determine the length of the chamber or learn to fire form. After the case if fire formed apply the l' leaver policy': Or learn to measure the length of the case from the shoulder to the head of the case.

F. Guffey
 
Using a L.E. Wilson cartridge case gauge of the appropriate/correct caliber, just drop the fired round into the gauge measure with a depth mike to adjust the sizing die spot on, I usually adjust my dies to move the shoulder back .001". Using this method if you don't have a depth mic a 6' steel ruler used as straight edge can be substituted.. Never have I had a case head separation nor a ring around the case to indicate the case was thinning and may separate using this method.. By the way I like Guffy's method too, I do not believe a case should have the shoulder moved back several thousands every time a case is fired and resized, the minimum required sizing is desirable for long case life.. William
 
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"...set by the belt..." Headspaces on the belt, not set. However, cartridges do not have headspace. Headspace is a rifle manufacturing tolerance. You cannot change that by how you resize.
 
The problem is tolerances. Take a look at the SAAMI drawing for the 300 H&H. The leading edge of the belt is allowed to be anywhere from 0.212"-0.220" from the bottom end of the case. The chamber recess that the belt seats against may be anywhere from 0.220"-0.227" forward of the breech face. That means, if you buy a case with the minimum amount of belt distance from the back of the case and have a chamber cut with the maximum depth, you have a 0.015" gap between the two, and the case head will have to back up that much and will stretch some brass doing it. Only if you find cases that are exactly at maximum and have a chamber that is exactly at minimum, will you prevent it. This only happens by accident once in a long while. Mostly things are about half way in between, and this is the reason belted cases have a reputation for not giving you many reloads. A 0.0075" average stretch is almost twice what an average .308 Winchester case has put up with.

The solution many use is to size to set the shoulder back a thousandth or two, like any rimless case, and let the chamber shoulder serve as the headspace determining surface for the case, rather than the belt shoulder in the chamber. It just reduces how much stretching and resizing the case has to go through every cycle, and that extends its reloading life.


P.S. If you choose to, you could buy up a large enough quantity of a single lot of your favorite brass to last what you estimate will be a lifetime, and get a reamer ground to match it. What constitutes a "match" will depend on your purpose for the rifle. For target shooting slow fire and loading singly, it can be quite tight, including very little extra room in the neck to minimize resizing change. For hunting, you want a bit more room to ensure rapid follow-up shot feeding. You can work that out with the reamer maker.
 
cartridges do not have headspace.
Click to expand...

I agree, we do have a member that called SAAMI, I do not know if he mentioned me by name but our member insisted SAAMI got it wrong. All I said was something about SAAMI specs omit the symbol for head space in their case drawings.

R. Lee in his book about modern reloading include the datum diameter.

F. Guffey
 
SAMMI has a shoulder datum diameter on both the case and chamber, together with a letter B for "basic" dimension. Even the belted magnums have that shoulder datum defined. But the headspace dimension has two differences: One is that, unlike the case's dimension that corresponds most closely to the chamber headspace dimension, the headspace dimension of the chamber is not expressed as a unilaterally toleranced number. Instead, because the minimum and maximum headspace numbers are both considered critical, the SAAMI drawing gives both of those numbers separately. The other difference is that each of those chamber headspace numbers has the headspace symbol, a circled X, next to it.

For those not familiar with engineering drawing practices, unilateral dimensions are given where one end of the tolerance range is considered critical and the other is not. For a cartridge, if you make it a little too big you cannot chamber or use it at all, whereas if you make it a little too small it still shoots, even if it is less accurate or has poorer case life. So the maximum length is the critical value, and thus linear dimensions for the cartridge are given at their maximum values (the critical numbers to be able to chamber the cartridge) with a minus tolerance only, instead of the more familiar plus and minus tolerances you see on things where an error in either direction is not a critical value (a value that stops a thing from being assembled or working at all).

For the chamber, it is the other way around, with too small being the error that it is critical to avoid, as that could prevent chambering and function, too. But slightly too big would still function, so the chamber linear dimensions are given as minimum numbers with plus tolerances only. Except for headspace. Headspace being either too large or too small are both considered critical, one for fit and the other for safety, so both are given: A minimum and a maximum, and no tolerances are needed with that range fixed by critical limits.
 
Shazbot ! ! Now what do I do? I want to keep this a simple as possible so, if I re-size cases using my RCBS 300 Weatherby die then either run all the cases through Larry Willis' sizing die or chamber each in the rifle, will I be ok?

The brass I'm loading is once fired Weatherby brass but the rifle used is not my rifle.
 
The belted case was developed because when shoulder type cases are necked up the shoulder tends to disappear and not provide enough case support; the result can be misfires. One answer would be to use a rimmed cartridge.

But a rim tends to be a problem in feeding from a magazine rifle. So the belt is simply a smaller rim moved forward. It does not provide additional case strength, it serves only as a support and headspace point.

As with shoulder type rimmed cartridges, sizing dies can be set so that the chambered cartridge will contact the chamber at both the rim/belt and the shoulder, and that has advantages in case life. But the real headspace is on the rim or belt, not on the shoulder. A gap at the shoulder allows the shoulder to expand, and repeated sizings will affect case life. But excess headspace at the belt/rim can allow the case head to move back and bulge or burst.

Jim
 
If the brass isn't once fired in your rifle, I'd suggest that you FL size it and shoot it in your rifle. Then, as UncleNick says, from then on resize like you would with a non-belted case and size just to bump the shoulder back a touch and henceforth headspace on the shoulder.
 
My 300 Weatherby MkV with my dies and the cases show severe case stretching and the real possibility of a case separation after only 3-4 loadings. Started out thinking only of the belt headspace but you definitely need to concentrate on only pushing the shoulder back from fired dimensions about .002" or you will get dangerous case stretching just in front of the belt. Check inside your cases for stretch marks and buy some case gauge that will allow you measure how much you push the shoulder back when sizing. The Hornady headspace gauge set will work.
 
I full length size with an RCBS die. I follow directions by screwing the die into the press until it touches the shell holder then I lower the ram and turn down the die another 1/8 to 1/4-ish turn. Is this sufficient to push the shoulder back where everyone is telling me?
 
Pogybait, you've asked a good question, but the answer varies. You may or may not be setting the shoulder back too far. It depends on your rifle chamber and how well the die matches the chamber. I'm guessing that after one firing, the fired case will still chamber easily. If it was me, I'd neck size and shoot that case till it became snug to chamber. Then I'd back the FL die out far enough, run the snug case up into the die, screw the FL die in till you can feel the case, back the case out, screw the die in half a turn and resize the case. If it still chambers snug, screw the die in a quarter turn or less and resize again. Repeat till the resized case chambers easily and then lock down the die ring. Others are big into measuring, and that's fine if you have the gear to do it. Results are the same, pretty much. I'm just outlining what I'll call the Braille method - doing it by feel.

Ya just need to start with a snug case or you are adjusting from an unknown point.
 
Probably using that method with firm contact and cam over you ARE pushing the shoulder back further than necessary and probably too much. Lots of loaders say to size brass without a case headspace gauge that you should turn the die in to touch the shellholder then back it "out" 1/8 turn. Size the case and check it in your rifles chamber. If the bolt won't close or is snug turn the die in slightly and recheck in your chamber. When it just closes with no resistance then lock the die down and size all cases. You may want to turn the die in about .002" past where it chambers with no resistance to make sure all cases chamber easily. Again, check the inside of your fired cases just in front of the belt as this is where the stretching in belted cases occurs. You can see the depression and feel it with a bent sharpened wire. Oversizing the shoulders on a belted case and you will get dangerous case stretching. You could remove the expander spindle while doing multiple sizing on the same case to prevent overworking the case neck but check after final sizing to make sure the neck expander doesn't change the fit in the chamber.
 
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RG1,

I like what you say. Just yesterday, I pulled out my Weatherby cases to begin prepping them for loading after not touching them for almost 15 years. My first attempt proved less than favorable because I had cases sticking in the chamber. I thought it was because I had not full length sized them properly. It was at that point I retired the 300s because I had plenty of factory ammo.

A couple of years ago, I loaded some 7mm Remington magnums. Again, I had problems with sticking cases so after doing some research, I learned bulging above the belt can sometimes be a problem on belted cases. I now believe my original 300 stuck cases were because of a bulge and not because the case was too long at the shoulder because I am sure I followed directions properly for the sizing die. I must have been closing the bolt a bit too hard on some tight cases. I remember seeking help from the range safety officer. We had a hard time opening the bolt.

During my research, I learned of Larry Willis' collet sizing die, which I bought. It solved my problem with the 7mm. If you are not familiar with his die, you use it to remove the bulge and to see if any cases need collet sizing. Yesterday and today, I full length sized some Weatherby cases then tested them in the collet die. The ones that passed the collet die test were then tested in the chamber of my Weatherby; there were no problems. The ones that did not pass the test were then run through the collet die and then chambered in the rifle. Again, there were no problems.

Perhaps I'm being a bit stubborn but it seems if I full length size properly then collet size cases needing the collet and all cases chamber properly, I shouldn't have any problems with loaded rounds. I don't plink with my Weatherby, for obvious reasons, so it's likely these cases will see only one reload.
 
Pogybait, What do you do with your Larry Willis die?

I have never had an infatuation with Larry Willis dies, I do not own one. I do have dies that return cases to minimum length/full length size, I also have small base dies for belted magnums. I do not use them but I have them JIC.

Then there are reloaders that have a resistance to learning, again, I was asked to form 450 belted cases for a wildcat chamber. FIRST!:eek:, make every attempt possible to understand: If they could have formed the cases or if every attempt they made when forming cases did not end in failure, they would not have ask me to form the cases for them.

First I had to determine if it was possible, it was. I formed 8 Remington magnum, Large Weatherby and 300 Win Mag cases, anything shorter would not work.

Out of the 450 cases 40 would not fit the #4 shell holder, the case in front of the belt had expanded .014"+. The 40 cases were in two boxes of 20 rounds each. Both the builder of the wildcats and my self could have "fixed' the cases, we both have lathes with collets. To make a point I took a gasket cutting hammer to drive the cases into the shell holder. I explained to the builder the cases had been hammered with heavy loads, I explained to him we could reduce the diameter of the extractor cut and use a collet in a lathe to 'fix' the hammered cases.

And then I explained why the cases expand in front of the belt, he not being hard headed and is not resistance to learning decided he did not need the hammered cases. OR! He was going to fix the cases after I left.

Reloaders have an infatuation with 'HEADSPACE' and as you all know we have some that insist there is a sequence of events that apply when the firing pin strikes the primer.

My opinion, manufacturers do not make cases for a reloader that knows what he is doing, they do make cylinder brass and 280 Remington cases and cases can be purchased from firing ranges that have been fired in trashy old chambers.

F. Guffey
 
Guffey,

I explained this earlier. After full length sizing with my RCBS die, I slide each case into one end of the Willis die. If the belt touches top of the die, that case is good to go and has no bulging problems and is ready for priming, charging, and bullet seating. If the belt does not touch the top of the die then, those cases have a bulging problem and will be re-sized with the other end of the Willis die. I have many 300 cases that have been full length resized with my RCBS sizing die that pass the no bulge test and that will chamber in my rifle nicely.

I don't want to get into an argument about Larry Willis and whether his dies and other pieces/parts are worth purchasing or whether they do what is claimed. It appears to me you have a problem with Larry. What he has told me about bulging and how his die corrects the bulging problem makes sense to me and, when I use his die, my problems are solved. If you are concerned about me spending money on something you wouldn't buy, not to worry because the die was given to me.
 
If you are setting you die to 1/8-1/4 down you may be over sizing the shoulder. I would try a few with 0 down and then do what you have been doing to test them.
 
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