Why did this happen; What do I do

[KyleC]

About 100 cases in resizing mixed 7remmag I had one separate at the belt.

First, how do I get the rest of the case out of my resizing die?

Second, why did this happen?

Third, what would you do with the rest of the same headstamp?

[blairmckenzie1]

Are you using case lube?

[Youngeyes]

Probably not enough lube. Don't know how, or if, you can remove it. The normal stuck case products require a base to work with. I would send it in to the manufacturer and let them remove it. It's probably not the head stamp you should worry about, but how often fired is the brass and that you use enough lube. Good luck.

[KyleC]

Lube: Yes. I use case wax, I keep it on my fingers and spread it over the case and neck rim.

I bought the brass as "once fired", so in reality, who knows.

[Steve RA]

Whatever the gun was fired in probably had too much headspace, the case stretches and gets thinner toward the base and eventually there will be a separation. Also possible it wasn't "once fired".

[Guy Neill]

Belted cases technically headspace on the belt. Regrettably, the shoulder dimension becomes a reference only and is commonly cut too deep, allowing the case shoulder to blow forward upon firing.

In extreme situations, one firing is enough to significantly stretch the case.

When loading for a belted case it is best to treat is as a rimless and adjust so that headspace is more effectively on the shoulder as with a rimless botteneck case. It will greatly enhance case life.

With fired cases from an unknown gun, it's a toss of the dice, but check the case length to see if it is longer than specified. Use something like an RCBS Precision Mic to determine hte chamber shoulder dimension and adjust your sizing accordingly.

Guy

[dauntedfuture]

Yes, belted cases headspace off the belt. You should not used brass fired from another rifle in a belted magnum as the shoulder reference from one rifle to another can very drastically. Many times you will get the shoulder set back just so and the belt has grown a little. Belted magnum cases are a pain to load. Years ago I bought 300 sticks of fired 30-338 brass. I tried and tried but in the end I recycled the brass. I suggest not using range pick up or once fired magnum brass.

I would not pay attention to headspace in a magnum rifle. Pay attention to setting back the shoulder .001-.002 with a FL die. You can get a special die to bump back the belt if needed.

So, why did this happen? The magnum case have a big and thick rim on them when compared to .308 or .223. I have never managed to stick .223, but have stuck several .308 cases when I missed lube on just one case. As a result, the rims on a .223 or .308 just pull right off. In that belted magnum case, the case split at the weak point, the point where the brass has stretched. Depending on the rifle, you can wear out magnum brass after one firing if your not careful.

I

[KyleC]

Thanks for the help and easy to understand explanations of belted magnums vs. non-belted cases.

I am using RCBS dies and set the 7mag the same as the non-belted(screw down until touching the shell-holder, then 1/4 turn more). So I'm assuming the 7mag die is made to head-space off the belt since I set it up the same as my others, but still had this happen?

[Tom D.]

KyleC,

I have a batch of Win cases that have been fired about 5 times in my 700 and re-sized with about .002 shoulder set back, in other words just like a rimless case. The set up you used is just about guaranteed to result in excessive sizing and subsequent case stretch. Get a RCBS case mike or similar tool and set your die to set the shoulder of cases fired in your rifle back .002-003". This has (obviously) worked well for me. Good shooting!