Is that the sort of "collet" die that squeezes the belt and the small area just ahead of the belt?
extending case life in belted mags
- Thread starter wce323078
- Start date
Is that the sort of "collet" die that squeezes the belt and the small area just ahead of the belt?
- Location
- AB foothills
Yes.
No truer words were ever written. I have found, however, that the problem is more prevalent on belted cases as they can be shot in chambers that would have severe headspace problems in non belted cartridges that headspace on the shoulder. Inital firing of these small for chamber belted cases can stretch the case far more than is indicated by measuring the stretch in FL or NS cases. Like cases sized up in caliber or having the shoulder blown out and forward when fireforming improved or wildcat cartridges these cases can actually stretch a lot without actually having any, or very little, measurable increase in length upon resizing. In fact a case that appeared to stretch 0.010- 0.012", which is about normal in the FL sized belted magnum cases I have worked with, may have stretched 0.015-0.020" on initial firing. This problem can only be minimized by partial FL sizing or Neck sizing as described by ther posters. The initial case damage is done.
I am at the stage in my life that I no longer want to "fix" the problems inherent in cartridge, chamber, barrel and rifle design. To that end I have designed my own EXTREME wildcat cartridges and have them built on custom rifles using reamers and dies built to my specifictions. My dies are custom made to form new brass to minimum specs or slightly smaller in diameter at the shoulder while not moving it. The chamber is then cut to minimum specs with the shoulder at the same length as the new brass. On firing the neck and shoulder are blown out minimaly while maintaing the same shoulder angle as the new brass. This creates a measured headspace of 0.0005" - 0.001" when measured at the shoulder datum line. I then run the fired brass through the dies,set the same as when forming new brass, and have a case identical to the newly formed case.
As there is no fireforming of cases there is no case stretch attributed to this process. The result is that I have fired some Winchester cases three times, in my 20 EXTREME and have only about 0.003" case stretch. The 6.5 EXTREME has slightly larger chamber tolerances but still got less than 0.003" case stretch on first firing/resizing. Velocities and groups are the same from fired/resixed cases as from new cases as the charge does not have to be changed. Accuracy due to rifle and case design is superb.
As I stated in my post, there should not be a problem unless you have a defective chamber. I should have also included defective dies. What you are describing is defective chambers and/or defective dies. Chambers and sizing dies are built to SAAMI and CIP specifications so cases fit the chambers. If they are defective or out of tolerance then of course they don't fit. Suggest the root cause of the problem be addressed under warranty instead of buying a $100+ die to patch it over.
And yes, I have had guns which could have used this magic die when I was trying to interchange brass from one gun to another. But the facts are that is a poor practice at best, and it is cheaper just to buy new brass, or keep it separated.
seeing as no one seems to have answered the OP ??
I will try
Hornady I think makes tapered expanders.
but depending on your cartridge, you might be able to get the next diameter up and size down the neck to make the "false shoulder"
another option I read about was to use a small O-ring just ahead of the rim on a rimmed cartridge to create the shoulder headspace. I can't see why that would not work on the belted. Just get a small O-ring and run it onto the case from the neck down onto the belt, and squeeze 'er home... and fire. You should get perfect headspace then. Then adjust your sizing dies accordingly
I will try
Hornady I think makes tapered expanders.
but depending on your cartridge, you might be able to get the next diameter up and size down the neck to make the "false shoulder"
another option I read about was to use a small O-ring just ahead of the rim on a rimmed cartridge to create the shoulder headspace. I can't see why that would not work on the belted. Just get a small O-ring and run it onto the case from the neck down onto the belt, and squeeze 'er home... and fire. You should get perfect headspace then. Then adjust your sizing dies accordingly
Here is a link to the K&M case neck expanding tools. This is probably the best way to do what you want to try. I haven't read the article in Shooting Times so cannot comment. If this actually helps to delay the onset of incipient head separation in cases, fired in belted magnums with excessively over sized chambers, it would be a worthwhile endeavor. I have had case head separation on belted magnums after as few as two firings in spite of setting the FL die to bump the shoulder. Let us know how you make out.
http://www.kmshooting.com/catalog/case-neck-expanding-tools/expand-iron_complete.html
http://www.kmshooting.com
Last edited:
Hi H4831
Probably a silly thing to ask but would a Mauser action (I'm thinking Win. 70) accomplish this to any degree ?
Innovative
Regular
- Location
- Casselberry, Florida
Take the Guess Work out of Loading Belted Calibers ...
My website shows the patented Belted Magnum Collet Resizing Die, and it explains (in great detail) the reason for headspace separation and case bulge. It also shows a much improved headspace measuring tool that replaces the RCBS Precision Mic (and several other reloading tools).
Case bulge is commonly misunderstood by most reloaders (even those with 40 years of experience). I have a full page on Reloading Questions and Answers that explains the reasons why it takes a bit more information to handload belted calibers. There are over 130 webpages that go beyond what you will find in the reloading manuals.
Check it out ...
My website shows the patented Belted Magnum Collet Resizing Die, and it explains (in great detail) the reason for headspace separation and case bulge. It also shows a much improved headspace measuring tool that replaces the RCBS Precision Mic (and several other reloading tools).
Case bulge is commonly misunderstood by most reloaders (even those with 40 years of experience). I have a full page on Reloading Questions and Answers that explains the reasons why it takes a bit more information to handload belted calibers. There are over 130 webpages that go beyond what you will find in the reloading manuals.
Check it out ...
It is nice that you have come to a Canadian forum to promote your product, but I would suggest that the die is unnecessary for belted magnum reloading. Magnums do not use any significantly different pressures than so called regular cartridges. Brass yields on every firing and provides no significant strength in any case. For that reason magnum cases need no special treatment.
Yes, cases fired in oversized chambers probably cannot be resized to standard dimensions so they will fit a normal chamber. However, it is a poor practice to mix brass from one gun to another in any case. Your special die is so expensive that you can buy a large bag of new brass and provide the proper solution to the problem (bad brass) for less cost.
I've owned two belted magnums and shot thousands of rounds, and had no need whatsoever for a special belted magnum die. The secret to making brass last in a belted magnum is the same as a regular cartridge, knowledge. Keep cases segregated, don't bump the shoulder excessively, and anneal the neck if you want maximum life.
Actually, it looks like he's been here about 2 years longer than you, and most of his posts seem pretty useful.
Innovative
Regular
- Location
- Casselberry, Florida
Common Misunderstandings ....
Ron AKA ......
You're right about the pressure of belted magnums being about the same as other cartridges. However, the case bulge problem has nothing to do with high pressure. It's caused by excessive chamber clearance of factory loads and the limitations of conventional die travel due to the belt. That's why belted calibers do require special treatment.
Also, it makes little difference if your chamber is tight or not, and it makes very little difference if you're loading for one rifle or a dozen different rifles.
You're also right about not bumping the shoulder excessively. In fact, it's best to bump the shoulder -.001" to -.002" at the most, and that requires accurate measuring.
(That's what our Digital Headspace Gauge is for.)
Here's the problem:
Factory belted ammo headspaces on the belt, and the shoulder gets blown forward .015" to .025" at the very first firing. That stretches, thins, and weakens belted cases far more than any non-belted case will ever experience. After that, the cumulative wear from reloading (pushing downward on the case) eventually causes a bulge at the weakest place - just above the belt.
A case bulge can easily be measured with ordinary calipers. In fact, the top of our collet die is a case width gauge that shows when a little "extra" resizing is needed. Once a case is bulged, it is prevented from entering far enough inside a resizing die. If your sizing die is too tight (like a SB die) it will just plow the brass rearward against the belt. After I designed several prototypes, the collet die proved to be the best method to move brass only inward.
My website shows and recommends many of the best reloading products that are made by several different companies.
(I don't sell their products, and I don't accept any paid advertising.)
Read this information, and you'll see the advantage of using modern reloading tools. So far, over 4,700 shooters are now using these two reloading tools of mine. I've talked to many of them in the last 10 years, and I'm pretty sure they know what they're doing.
- Larry
Ron AKA ......
You're right about the pressure of belted magnums being about the same as other cartridges. However, the case bulge problem has nothing to do with high pressure. It's caused by excessive chamber clearance of factory loads and the limitations of conventional die travel due to the belt. That's why belted calibers do require special treatment.
Also, it makes little difference if your chamber is tight or not, and it makes very little difference if you're loading for one rifle or a dozen different rifles.
You're also right about not bumping the shoulder excessively. In fact, it's best to bump the shoulder -.001" to -.002" at the most, and that requires accurate measuring.
(That's what our Digital Headspace Gauge is for.)
Here's the problem:
Factory belted ammo headspaces on the belt, and the shoulder gets blown forward .015" to .025" at the very first firing. That stretches, thins, and weakens belted cases far more than any non-belted case will ever experience. After that, the cumulative wear from reloading (pushing downward on the case) eventually causes a bulge at the weakest place - just above the belt.
A case bulge can easily be measured with ordinary calipers. In fact, the top of our collet die is a case width gauge that shows when a little "extra" resizing is needed. Once a case is bulged, it is prevented from entering far enough inside a resizing die. If your sizing die is too tight (like a SB die) it will just plow the brass rearward against the belt. After I designed several prototypes, the collet die proved to be the best method to move brass only inward.
My website shows and recommends many of the best reloading products that are made by several different companies.
(I don't sell their products, and I don't accept any paid advertising.)
Read this information, and you'll see the advantage of using modern reloading tools. So far, over 4,700 shooters are now using these two reloading tools of mine. I've talked to many of them in the last 10 years, and I'm pretty sure they know what they're doing.
- Larry
I do measure my cases and chamber dimensions vary. Some are poor and some are not. And, the chamber dimensions do determine the size of the fired case. While the belted magnum is designed to headspace on the belt, there is no reason for the barrel maker to put excessive space at the shoulder. Some do, and some don't. In any case this is a one time event and this headspace issue is resolved on the first time the brass is fired. The belt controls the headspace and the cartridge fire forms perfectly to the chamber. It only becomes a problem if the handloader repeatedly bumps the shoulder back unnecessarily, and makes the case not fit the chamber again and again.
The same can be said of the collet die. There is no reason to keep swaging the head end of the cartridge back down to the original undersized SAAMI dimensions if the gun has a large chamber. All you are going to do is cause it to fail earlier.
As I said earlier the thought that belted magnums need special dies is nonsense. The head end collet die is a solution in search of a problem. In 45 years of reloading belted magnums I have not discovered this "problem". I get 20 reloads per case, before they die of a neck split. If I annealed the necks, I'm sure they would go much longer. This is with shooting over Hodgdon recommended loads of H4831.
Innovative
Regular
- Location
- Casselberry, Florida
Whatever ....
Ron AKA ......
Although you have not personally encountered bulged belted magnum cases in your 45 years of reloading, there are many very competent shooters that are quite familiar with it.
About the only real experience I have is 30 years as a professional gunsmith with 10 of those years in the development of reloading equipment, resulting in two U.S. patents. I have also worked directly with thousands of shooters including the U.S. Secret Service, and several world record shooters.
For some reason, I guess we'll just have to agree to disagree with each other.
- Larry
Ron AKA ......
Although you have not personally encountered bulged belted magnum cases in your 45 years of reloading, there are many very competent shooters that are quite familiar with it.
About the only real experience I have is 30 years as a professional gunsmith with 10 of those years in the development of reloading equipment, resulting in two U.S. patents. I have also worked directly with thousands of shooters including the U.S. Secret Service, and several world record shooters.
For some reason, I guess we'll just have to agree to disagree with each other.
- Larry
No. Ron AKA has explained it very well. And while I explained a way to keep from damaging first fired brass in a rifle with excessive head space, belted or not, the fellows are accomplishing the same thing with a belted, by using the rubber O ring, to keep the cartridge head tight against the bolt face on the first firing. After that first firing, my way or theirs, the undamaged case will perfectly fit the rifle chamber. From then on, set the die to just kiss the shoulder, and it will head space on the shoulder, everafter.
Thanx again H4831. I have ready access to plenty of O-rings so I'll give that idea a go.
I've been to the range for the first time with my new Win Mod 70 and I've taken some measurements on the 1F brass with an RCBS Case Master Gage. The caliber is 300 Win Mag.
From what I can tell, the shoulders of my 1F brass have moved forward 10 to 12 thou. Does that seem about right ? Is it good or bad ? I've had to innovate ( use an inverted 45 ACP case) to take the relative head to shoulder measurements as the RCBS Gage has no specific tool for this.
Also, with both the Previ and Winchester brass that I've used, runout at the case neck varies between, less than a thou (7), less than 2 thou (20), and 3 thou + - (3).
I'm taking the best of these measurements to indicate that the chamber is good. Does that make sense?
Lastly, the RCBS gage has an "L" tipped arm that, inserted into the case, supposedly is good for measuring case wall uniformity against the gage over the length of the brass. It all looks good but I'm wondering just how far in front of the belt a stress ring would normally form ? Its impossible to set the foot of the gage immediately in front of the belt. There are no external stress signs whatever.
All this is just my amateur attempt to ascertain if things appear normal so far. I expect as much, but any confirmation or comment from you guys would be reassuring,, I hope
.
From what I can tell, the shoulders of my 1F brass have moved forward 10 to 12 thou. Does that seem about right ? Is it good or bad ? I've had to innovate ( use an inverted 45 ACP case) to take the relative head to shoulder measurements as the RCBS Gage has no specific tool for this.
Also, with both the Previ and Winchester brass that I've used, runout at the case neck varies between, less than a thou (7), less than 2 thou (20), and 3 thou + - (3).
I'm taking the best of these measurements to indicate that the chamber is good. Does that make sense?
Lastly, the RCBS gage has an "L" tipped arm that, inserted into the case, supposedly is good for measuring case wall uniformity against the gage over the length of the brass. It all looks good but I'm wondering just how far in front of the belt a stress ring would normally form ? Its impossible to set the foot of the gage immediately in front of the belt. There are no external stress signs whatever.
All this is just my amateur attempt to ascertain if things appear normal so far. I expect as much, but any confirmation or comment from you guys would be reassuring,, I hope
.
Innovative
Regular
- Location
- Casselberry, Florida
HKMark23 .......
The first firing of a belted case usually stretches the case between .015" to .025" at the shoulder, and that weakens the case. The exact amount of chamber clearance (at the shoulder) depends on the size of your particular chamber.
If you accurately minimize shoulder clearance, it should reduce case run-out to .001" maybe .002" at the most. The exact location where headspace separation occurs varies depending on the manufacture of the cases you're using.
Signs of case stress are first found "inside" the case about .060" above the belt.
The first firing of a belted case usually stretches the case between .015" to .025" at the shoulder, and that weakens the case. The exact amount of chamber clearance (at the shoulder) depends on the size of your particular chamber.
If you accurately minimize shoulder clearance, it should reduce case run-out to .001" maybe .002" at the most. The exact location where headspace separation occurs varies depending on the manufacture of the cases you're using.
Signs of case stress are first found "inside" the case about .060" above the belt.
The only way you will get into a problem is if you keep resizing the brass with a FL die and each time you reload you push the shoulder back that 10 to 12 thou. Even if all you have is a full length die, you can do a partial full length and only size 2/3 of the neck. This will not push the shoulder back. If the case starts to get snug on closing the bolt, then push the shoulder back 0.001-0.002" only. Your tool made from the 45 ACP should let you do that.
Like Ron, I've never run into magnum bulge yet either. I've sectioned 300WM brass that has been fired 12+ times and have not seen any significant thinning. Not saying the bulge doesn't happen, just that I'm not going to order a bulge buster until I do.
Now a primer pocket shrinker would sure come in handy.....
Now a primer pocket shrinker would sure come in handy.....
Thanx again for the helpful responses guys. My dies include a neck sizing die so I'm using that now and will resort to bumping the shoulder a thou or two with the FL die when necessary. So far this certainly seems like much ado about nothing, as Ron et al have advised it would be. Again, I appreciate your helpful assurances.
