6.5 - 06 Case Separation Help Request

Northman999

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Hey all, I’ve run into a bit of a problem with rifle I picked up on the EE lately.

It’s a Swedish Mauser 96 rechambered from 6.5x55 to 6.5-06.

I took it to the range a couple of days ago to work up some loads in sight in a scope, and I noticed distinctive rings on the brass maybe 15 mm from the base on some of the early rounds I fired. I also had about five case separations in about 20 rounds fired. All of the case separations were exactly on the line where I could see marks on the brass that had not separated. This brass was once fired 270 Win brass then reloaded for 6.5-06, so it was twice fired in total. No way I should have case separations.

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I inspected my brass and put the micrometre on it, and the micrometre confirmed there is a step in the brass near the base of about 10 thou, right where the brass is splitting, with the base being smaller. I looked up both 6.5 x 55 and 6.5-06 cases in my reloading manual and discovered that’s a 6.5-06 case is indeed 10 thou difference in the bases of each case. So, unpleasantly, no surprise.

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So, I’m wondering if any of you have any suggestions on what can be done here?

I am really wanting to salvage this as a 6.5-06. It’s an inexpensive rifle though so I’m not willing to put loads of cash into significant gunsmith work.

Thanks in advance!
 

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You can see the pronounced expansion ring where the solid head transitions to the sidewall of the case. That isn't surprising, considering that the 6.5-06 brass is smaller in diameter than the Swede.
But I don't think that is the primary cause of the incipient separations. That is more likely a headspace issue.
I would suggest that you try sizing the .270 brass incrementally, until the bolt will just close. You want to feel the case as the bolt closes. The case will then be well supported from both ends, and will not stretch when fired in the 6.5-06 chamber for the first time.
I would also be cautious about how hot you are loading the 6.5-06 cartridges.
 
A proper gunsmith would run from this situation. I have always been of the understanding that you should never rebarrel or in this case rechamber a receiver for a cartridge that will produce considerably more pressure that what it was originally designed for. The 6.5 Swede can generate around 40,000 PSI and your 6.5 06 can generate in excess of 56,000 PSI not to mention experimentation with various loads. I would be very very cautious around that rifle and fellow that did the work, you are playing a dangerous game.
The Swedish Mauser's are nice actions and can make sweet little custom rifles but they should be left as 6.5 x 55 chambers or rebarreled into similar cartridges like 7 x 57 for example. I suggest you either put a new barrel on it and go back to the original chambering or abandon it all together. D.H.
 
A proper gunsmith would run from this situation. I have always been of the understanding that you should never rebarrel or in this case rechamber a receiver for a cartridge that will produce considerably more pressure that what it was originally designed for. The 6.5 Swede can generate around 40,000 PSI and your 6.5 06 can generate in excess of 56,000 PSI not to mention experimentation with various loads. I would be very very cautious around that rifle and fellow that did the work, you are playing a dangerous game.
The Swedish Mauser's are nice actions and can make sweet little custom rifles but they should be left as 6.5 x 55 chambers or rebarreled into similar cartridges like 7 x 57 for example. I suggest you either put a new barrel on it and go back to the original chambering or abandon it all together. D.H.

Wrong action for a 6.5-06 for sure... and a bad chambering to boot. Dump the barrel and go back to a lower pressure cartridge.

But you say, "This brass was once fired 270 Win brass then reloaded for 6.5-06, so it was twice fired in total."

The brass was most likely weakened on the first fire forming and probably oversized for the next loading and weakened even more.

Correct fire forming is what gives the strongest case and the longest life.

If you can not firmly feel the bolt close on a prepared brass, you need to create a false shoulder by sizing the neck up and then resizing the case leaving enough of the false shoulder you created so you can firmly feel the bolt close on a brass.

Simply seating a bullet long so you feel the bolt close will not hold the case against the bolt face when fired... the firing pin will drive the case ahead over the bullet and then on fire forming the case will stretch back in the web area making a weaker case.
 
Will the Husky 1600 barrel fit a 96 mauser? It should be a small ring 98 and Tradex usually has barrels on actions with bolts missing etc.
 
Yes, I’ve glanced at Trade Ex. They have given me great service over the years. The only barrels that they have now that don’t have actions installed, add an obvious extra cost, are 6.5 x 55, but they’re very short like 18 1/2 inches, which I’m not into. I’ll keep an eye out for a barrel in a reasonable chambering that’s more in the 24 to 26 inch range. Thanks again.
 
6.5 by 55 has a larger case head diameter than a 30/06. Even making 6.5 by 55 cases from 30/06 type cases is problematic. Hate to say it, but you got took.

Grizz
 
What do the resized 6.5-06 unfired case heads measure?
And what do the fired case heads measure?
Usually you get case head separation from oversizing or headspace issue in my experience. I would guess that the 10 thou drawing spec size difference you see on the case heads between the 6.5x55 and the 6.5/06 is actually measured less. Like 5 thou or under and shouldn't be the main problem
 
Neck size, and when f/l sizing is required just bump the shoulder enough to chamber. I had a 375 H&H AI that had a loooonng chamber body and short neck. Took some experimenting to not destroy brass quickly. As far as pressure levels in your action, I defer to the experts.
 
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