Case seperation during fire forming

[TheDerkster]

I was forming cases for a 7mm Sherman short mag, and wasnt paying attention to my case quality because the first few were good. I went to eject and put another one in only to realize it would go in. Come to find out, I had the top if the case separate of from the body right at the shoulder body junction. I got the stuck piece out, and I know why it happened. I pushed the shoulders too far back some how. I though I had them good, buy I guess not. They are probably 70 thou to short.

Is it even safe to use these cases any more? It was virgin Norma brass, but I feel that after multiple runs do too a couple if hiccups in the press, it got over worked so im thinking about annealing it and that will solve the problem because many of them turned out good. I threw away anything with a slight ring. I didn't want to risk it. I also thought about lubing the cases with hornady unique .

What do you all think? I mean the brass is 150$ and I just basically ruined most if it if I can't salvage it, but medical bills are always much higher.

 

[ShtrRdy]

I'm not an expert at this by any means but I was wondering if you seated the bullet out far enough so that it was contacting the lands and forcing the back of the case into the bolt? That way it should blow the shoulder area out.

Since it's new brass it seems like you shouldn't have to anneal it.

 

[TheDerkster]

I'm not an expert at this by any means but I was wondering if you seated the bullet out far enough so that it was contacting the lands and forcing the back of the case into the bolt? That way it should blow the shoulder area out.

Since it's new brass it seems like you shouldn't have to anneal it.

I'm using cream of wheat and 13 gr of titewad.

 

[tbrice23]

I know 'hindsight is 20/20' but maybe size only enough to barely chamber easily.

Since it's too late for that you could,
1. trash all your brass
2. start seating bullets jammed .020"+ as was mentioned .

I know that you wanted to save barrel life and money on components by using COW but I think its too late for that.

 

[Rich Coyle]

Pull the bullets. Anneal the brass and seat the bullet way out so it jams the rifling. Fire for effect.

 

[TA1911A1]

Delete. wrong thread.

 

[Pdvdh]

Re: Case separation during fire forming

Expand the case necks to .308. Then resize the necks just enough to get the cases chambered with firm resistance on closing the bolt. Use the expanded neck to hold the case head firmly against your bolt face.

Then use the C-O-W method to fireform.

 

[LRSickle]

Pull the bullets. Anneal the brass and seat the bullet way out so it jams the rifling. Fire for effect.

Or you could create a false shoulder. That's always worked quite well for me. I tried both jambing the bullet into the lands and a false shoulder. Both have worked well.

I also wonder if removing your ejector would help. I haven't tried that but I wonder if it might help.

 

[TheDerkster]

Re: Case separation during fire forming

Expand the case necks to .308. Then resize the necks just enough to get the cases chambered with firm resistance on closing the bolt. Use the expanded neck to hold the case head firmly against your bolt face.

Then use the C-O-W method to fireform.

Now that's genius right there. Ill have to try that. I think my mode of attack is too buy a new batch of brass, size for crush fit, and go from there. I can work on this other problem when I have more time.

 

[Pdvdh]

Einstein for a day! At least for one post!

 

[TheDerkster]

Einstein for a day! At least for one post!

Your an engineer...I don't think you are lacking much there. Im minoring in engineering and math is my strong point so I do good at it but it's tough enough so yeah

 

[BountyHunter]

Put a very light coating of lube on the case shoulders next time. Helps the shoulders form easier without neck separation.

 

[LoneTraveler]

The cases that have been fired are already damaged to a point, Each case will have to be checked and judged whether safe or add them to the junk brass bucket.

The cases that have not been fired can be recovered with work.
If the rifle has a spring loaded ejector I would remove it. (Example 700 Rem action).

Remove the bullets from the cases. Resize the case necks. Hope you have a bushing sizing die, So the powder and cream of wheat won't have to be removed. For Safety Sake if you have to remove the Powder and Cream of Wheat, Junk them. Charge with powder and Fill the case full of Cream of Wheat. And then seat the bullet till it fits tight into the lands of the rifle and compresses the Cream of Wheat tight. Between the extractor and the Cream of Wheat assisted bullet tension the case should be held tight against the Bolt Face till the primer is fired. This should allow the case to fit itself to the chamber properly without many problems.
Good Luck and be safe.

 

[Schnyd112]

This is the first time I have hear of a case separating at the body/shoulder junction. I have heard of guys leaving the necks in the chamber, usually from cutting too deep while neck sizing, or from high pressure belted mags separating above the belt, but this is new. I had to reply for nothing more than information.

Sorry I couldn't help.