Perplexing issues with a 280 Rem!

dthunter, if you confirm the headspace for the brass that you are using, you will likely find that headspace is too short. So when you fire, the case is expanding a lot and you get that separation. Nickle plated brass is far more rigid then reg brass so more prone to splitting. Why we don't use it for reloading when possible.

Setting the headspace to a crush fit by necking up and down is the perfect way to ensure your brass will fireform to the chamber properly. I will do this for my custom wildcats and form using cream of wheat or cornmeal and a light powder charge.

Once the shoulder is set to the chamber headspace, normal pressure shooting leads to very long brass life.

Sound like you have this well under control but let me know if you have further questions. Thanks

Jerry
 
rokoro said:
I purchased a couple hundred Winchester brand nickel plated cases for one of my 280's. I noticed that while they all had 280 Rem headstamps there was some differences in the cases. Some were properly formed 280 cases that had the shoulder moved forward approx. .050" to where the shoulder is on a 30-06 case. Some cases were sized to 30 and did not have the shoulder moved forward. I had to size these cases leaving a secondary shoulder and fireform these cases. The third type of case I had was a 280 headstamp case necked to 7mm with the shoulder in proper place for the 30-06. This effectively created a cartridge with .050: headspace when chambered in a 280 rifle. These cases would stretch just as dlhunter has mentioned. I expanded the necks on these to 30 cal then resized back to 7mm leaving a secondary shoulder. Fireform and the problems are all gone. Quality control is a thing of the past. Hope that helps
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Thats exactly what I suspected, but wanted someone else to confirm this. Creating this false shoulder is what my plan is.

Thanks guys!
 
Jerry,

You are not 'setting the headspace' when you manufacture a crush fit by necking up and down... you are adjusting the case head clearance.

Head space is a fixed dimension set using a gauge when the barrel is fitted to the action ... case head clearance can be adjusted by the re-loading procedures as described.

I know you know that...

Dennis

Terminology is important, if it isn't used correctly, it becomes meaningless and is lost...
 
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guntech said:
It's the terminology... just to clarify some points...

The headspace of the rifle won't change. It is a fixed measurement that requires gunsmithing to change it.

What you are doing is correcting the cartridge case head clearance by making the case fit the chamber.

The term headspace is very often incorrectly used (by individuals and manufacturing companies as well) when describing what should be termed case head clearance...
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Thank You! :cheers:

Since the manufacturers started perverting the term 'headspace', I've seen more and more confusion among shooters in general over headspace.
 
DT Hunter ... when you remove the bolt and place a round into the chamber with light thumb pressure ... how much of the brass case is exposed above the barrel face?? It is possible that the headspace is fine BUT too much unsupported case exists beyond the case web
 
This is off topic but if a person only neck sizes the brass for the next firing, does a bit of excess headspace make any difference, would it not just fire form to the longer chamber?
 
AP said:
DT Hunter ... when you remove the bolt and place a round into the chamber with light thumb pressure ... how much of the brass case is exposed above the barrel face?? It is possible that the headspace is fine BUT too much unsupported case exists beyond the case web
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Sorry I cant give you that dimension because I am away at work for two weeks. I think that could produce problems, but I am positive its a case of poor quality control in forming cases. I will try this route first.

If there was too much clearance as you suggested, problems that would manifest themselves would show up as a bulged ring (increased diameter of the case) in that unsupported area.
 
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hawk-i said:
This is off topic but if a person only neck sizes the brass for the next firing, does a bit of excess headspace make any difference, would it not just fire form to the longer chamber?
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Thats the whole problem with exsessive tolerances like this. When the cartridge is fired, it will stretch to fill what ever space its in. If the case has too much "case head" clearance the case needs to stretch its self to fill the chamber.

Normally, when an undersized case is fired the case expands and seals against the chamber walls from the case mouth, back to the head.
"Thinnest part of the case to the thickest. When this happens, the case wall/body stays position and pushes the case head back to the bolt face. The case wall just ahead of the web is the area that stretches to accomodate this differential in volume. Thus this is where the case material thins out and creates a dangerously thin spot.

If any case is fired in this situation and the pressures are high enough to push back the case head, that case is sacrificed/compromised permanantly.

This is why I mentioned in my original post that the cases in question are distinctly longer than the rest. They are stretched and thinned out above The web of the case head.

The cases that are already fire formed AND not stretched will get the same neck expansion and partial reduction to create a false shoulder. This is one of two ways you can force the case to be fully supported from the bolt face to the shoulder position. This will create a conditon to produce a perfectly fire formed cartridge.


The other way to do this is to seat the bullets long so that when you close the bolt, it forces the case head against the bolt face, and the bullet ogive into the lands. Again, fully supporting the cartridge in the chamber. The only
Thing about this approach is that you can produce higher pressures from the bullet bieng jammed into the rifling lands. Done correctly, ifs just another fine technique.

Hopefully I have properly and accurately explained myself. Lol!
 
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Using a bullet jammed into the lands will not cause a case with excessive head clearance to stay against the bolt face for correct fire forming... when the firing pin hits the primer it will also drive the case forward over the bullet until a shoulder stops it... a bullet jammed in the lands will raise the pressures though... there is no substitute for shoulder to chamber contact...
 
dthunter said:
Maye you dont see what I am doing. by increaseing the caliber of the neck, then progressively sizing the cases back down untill the bolt can just close with some crush fit. This creates an ABSOLUTE perfect fit in the chamber and locates the case centered in the chamber.
This will indeed eliminate any potential issues with case fit in relation to headspace. I have used this technique many times with thousands of cases. My explaination of how I was going to do this was a little vague.
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Yep you are right, I have no idea what you are trying to do.

It is entirely possible to have a case that has too short a headspace and you can neck up and down as much as you like and that isn't going to change the headspace dimension one bit. But whatever, it isn't my rifle and I don't have to have my face near it when the trigger is pulled. So have at 'er Hoss and good luck to you.
 
guntech said:
Using a bullet jammed into the lands will not cause a case with excessive head clearance to stay against the bolt face for correct fire forming... when the firing pin hits the primer it will also drive the case forward over the bullet until a shoulder stops it... a bullet jammed in the lands will raise the pressures though... there is no substitute for shoulder to chamber contact...
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I have heard this debate before. It seems possible, but it has worked for years for many. Is it the BEST method? I dont think so either.


Thats why I personally prefer creating the false Shoulder for a slight crush fit. (As I stated in my previous posts)

"And" no potential pressure issues with the bullet jammed into the bore.
 
Suputin said:
Yep you are right, I have no idea what you are trying to do.

It is entirely possible to have a case that has too short a headspace and you can neck up and down as much as you like and that isn't going to change the headspace dimension one bit. But whatever, it isn't my rifle and I don't have to have my face near it when the trigger is pulled. So have at 'er Hoss and good luck to you.
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You have much to learn! As we all do.

Look it over, read what Guntech, Mystic, have been discussing.
We have been discussing termanolgy discrepancies more than anything.

The process of necking up a case neck to a diameter that is too big for the chamber will not allow you to chamber it.
Thats the first step.

The by using your full length die, start sizing just enough to "resise" 1/2 the neck length. Then try to chamber the case. It probably wont fit because the unsized portion of the neck is still interfering with the closure of the bolt.

Continue to adjust the die down in steps. Between each die asjustment, try chambering
The case. As soon as the case can be chambered with "some resistance, not really tight" when lowering the bolt handle, stop there. Be sure your locking lugs have a "little" lubrication here.
At this point the die is set properly. This allows the part of the neck of the "partially sized" case to support the front of the case and ensure the case head is firmly against the bolt face when the bolt is closed.

I hope This explaination is clear enough.
 
Suputin said:
Yep you are right, I have no idea what you are trying to do.

It is entirely possible to have a case that has too short a headspace and you can neck up and down as much as you like and that isn't going to change the headspace dimension one bit. But whatever, it isn't my rifle and I don't have to have my face near it when the trigger is pulled. So have at 'er Hoss and good luck to you.
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No, but it is a way to adjust brass that doesn't quite fit to the chamber, and thereby safely compensate for SMALL headspace issues. I've done it for various firearms with various issues. It can be a very helpful technique. - dan
 
i believe dthunter is bang on with his solution. after firing he will have a perfect fitting case to work with. many wildcats are blown out the same way.
 
dthunter said:
The process of necking up a case neck to a diameter that is too big for the chamber will not allow you to chamber it.
That's the first step.

Then by using your full length die, start sizing just enough to "resize" 1/2 the neck length. Then try to chamber the case. It probably wont fit because the unsized portion of the neck is still interfering with the closure of the bolt.
Continue to adjust the die down in steps. Between each die adjustment, try chambering the case. As soon as the case can be chambered with "some resistance, not really tight" when lowering the bolt handle, stop there. Be sure your locking lugs have a "little" lubrication here.
At this point the die is set properly. This allows the part of the neck of the "partially sized" case to support the front of the case and ensure the case head is firmly against the bolt face when the bolt is closed.
Click to expand...

As far as I am concerned this is "THE" way to make brass so it fire forms with the greatest strength...
 
dthunter said:
Thats a scarey thought! Lol!

I have not created the false shoulders yet on the cases. Thats the very next thing on my agenda. Next to Christmas shopping that is. I had to fly out to work this morning. I will be working for two weeks before I can get back to my project. Darn it!
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This occurs more often than one may think of, especially with powders with burning rates from H-IMR 4831 and slower and most of the times it's not enough to blow the gun (or the case). One particular sympton is high pressure signs with a starting load or with "weaker loads", especially true if the load densitry is less than about 80% of case capacity. And it's often also related to small caliber and large case capacity, or overbore calibers.
The best way to avoid this if a low density load have to be used, is by filling the case free space with a buffer.
Then, as already pointed, with a "short case" when the firing pin hits the primer, the case is pushed forward in the chamber and if the bullet hits the land and jams in the barrel while pressure builds up with enough strenght to stick the case sides on the chamber wall, then before the bullet starts moving again, the case head is pushed backwards which creates such a separation. And coincidently, it's also especially true with slower burning powders...
 
Baribal said:
This occurs more often than one may think of, especially with powders with burning rates from H-IMR 4831 and slower and most of the times it's not enough to blow the gun (or the case). One particular sympton is high pressure signs with a starting load or with "weaker loads", especially true if the load densitry is less than about 80% of case capacity. And it's often also related to small caliber and large case capacity, or overbore calibers.
The best way to avoid this if a low density load have to be used, is by filling the case free space with a buffer.
Then, as already pointed, with a "short case" when the firing pin hits the primer, the case is pushed forward in the chamber and if the bullet hits the land and jams in the barrel while pressure builds up with enough strenght to stick the case sides on the chamber wall, then before the bullet starts moving again, the case head is pushed backwards which creates such a separation. And coincidently, it's also especially true with slower burning powders...
Click to expand...


Absolutely! I am thankful that I can make the adjustments to continue my project.
Knowledge helps a shooter do that.

These forums definitely can really help hash out valuable information! Sometimes a guy only needs to hear a response from someone else to confirm a suspicion.

The hard/frustrating and needless part is dealing with "some" posters attitudes, when all you want to get is "EXPERIENCED" INDIVIDUALS to contribute "HELPFUL" information. Thanks guys!
 
It's pretty much the same process... Holding the powder in place so it's equally submitted to the primer's flame and controlling free space is all it's about.
A lot of incidents have occured from using "low pressure" loads using small amount of slow burning powders without buffers.
 
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