Indentations in brass - Any Ideas on the cause?

[Sandgroper]

I was going through my brass in prep for a shoot in a couple of weeks and came across this one.

Any ideas on what the cause could be?

It's 6.5x55 fired from my m/38 Husquvarna. I can't tell you the load, but judging from the flattened primer, it was most likely from a batch I was working up. I can only assume I missed the indentations on the day as I was checking for pressure signs on the primers.

It's only one with those indents. It's from brass that has been reloaded 4 times, the length is fine and I only neck size.

[20series]

It could be hydraulic pressure from too much lube when youve resized your cases possibly.

Alan

[Sandgroper]

It could be hydraulic pressure from too much lube when youve resized your cases possibly.

Alan

Alan,
That was my initial thought, that I had already prep'd it, messed it up and put in the wrong box.

I noticed the indentations as picked it up to decap and neck size. The primer was still in place - so I don't think it's that. Baffled. :?:

[The Gun Pimp]

Here's a pic that had me baffled - and still has! (Hope the pic is attached!)

It's a 22 Dasher case that I was fireforming with pistol powder and a wax plug. This was the only one of 50 that turned out like this.

Vince

[Sandgroper]

Vince,
Wow, that's bizarre. It's similar to my case but on a much grander scale. :lol:

[dromia]

I do'nt know if any of you remeber the portuguese FNM ammunition that was around a few years ago. The 6.5 x 55 Swedish ammunition was very prone to this. In that case the brass was very hard at the neck and didn't obturate very well so there was gas blow back and the dimpling of the case, also the cases were very sooty. When I annealed the fired cases it didn't happen again. I've also had this on 8 x 58R cases that I'd annealed too far down the case giving a soft shoulder there was also a generous throat on that particular Rolling Block so gas blow back was present.

For whatever reason in your particular cases it looks like blow back over the shoulder with the case obturating and sealing at the case head.

[spud]

Here's a pic that had me baffled - and still has! (Hope the pic is attached!)

It's a 22 Dasher case that I was fireforming with pistol powder and a wax plug. This was the only one of 50 that turned out like this.

Vince

vince i'll have an educated stab st this one


i am bettting that you were fireforming these one at a time as apposed to feeding from a mag i am wondering if that as you fed the case in to the chamber each time and the barrel has got warm a small drop of wax has melted or even dropped from a case and been on the out side of the chamber where apon firing hydraulic pressure and certain ammount of vaccum in side the case hase drawn the case wall inwards


by the looks of the crease in the case it was caused more by vaccum draw than by an out side force or possibly a little bit off both at the same tme

[Sandgroper]

The 6.5 x 55 Swedish ammunition was very prone to this. In that case the brass was very hard at the neck and didn't obturate very well so there was gas blow back and the dimpling of the case, also the cases were very sooty.

Dromia,
You Genius! :lol: I remember now that's why I was load testing - it's been a while since I last shot it. The cases were very sooty, and I was working up a load to get obturation. The powder was H4895 and I was approaching max load - hence the flattened primer - but still no obturation.

I had posed a question about the sooting on either GT or the old FB site and got no joy, that's when I tried the test loads. As the cases were still sooty I decided that H4895 was too fast and I was going to look at a slower powder. I then got injured and everything went on the backburner.

I now remember where my notes are as well! They're still in my ipod waiting to be transcribed.

[dromia]

:lol: :lol: :lol: :lol:

I do like a happy ending.

[The Gun Pimp]

Spud,

I would agree - definitely caused by a vacuum.

I was fireforming with half a case (15 gn.) of Bullseye and a wax plug.

I load one at a time with the rifle vertical - and fire it in the vertical position.

I'm sure the plug didn't fall out of the case but it could have dropped down the neck into the empty space in the case.

I like your soap idea - it should stick better than wax, though I usually 'cut' the wax with a bit of soft soap to make it less brittle.

Cheers
Vince