Bad Brass?

[WHG]

Can anyone explain what’s causing this? This was new Frontier brass loaded with a Sierra #2115 FMJ with 42.5 gr of IMR 4895 powder at an OAL of 2.870”. They were fired in both my 1896/11 and K31. Some cases looked fine, but out of 40 rounds I had about 8 that had these problems. I was also shooting some other reloads with everything the same except with Norma brass and GP11 without any problems. Neither rifle has ever damaged brass like this in the past and headspace is Correct.
http://i47.photobucket.com/albums/f181/b_gardner/Swiss%201_zps9d51gtrl.jpg (http://s47.photobucket.com/user/b_gardner/media/Swiss%201_zps9d51gtrl.jpg.html)

[4F4Nam]

No offense meant, but is that 7.5 Swiss brass? I ask because it appears that the shoulders are blown out round and necks are blown off straight forward?
Just sayin'.

Ed

[Sunray]

Frontier brass is supposedly a Hornady brand. Other Internet forums says it's garbage.
Appears that the middle case is seriously corroded too.

[WHG]

It was brand new 7.5 brass that had never been loaded that I bought from Grafs. I had these cases sitting on my reloading bench for awhile before taking the picture and the middle case got splashed with some cleaner which is why it looks like it's corroded. I'll take a picture of the base of the shells. The primers looked normal with no signs of over pressure.

[joem]

Chronograph a few to make sure they are in spec.

[PWC]

Chronograph? I don't think I would let these anywhere my rifle until I took them apart and checked / measuerd everything first. check for shoulder set back.

[WHG]

The shoulders may appear rounded in my pictures, but they match up to new unfired GP11 brass very closley. I took apart some that I hadn't fired yet and confirmed the correct powder and charge were used. I have 80 rounds that I haven't fired yet that I plan on taking apart and annealing. I'll then load a test batch and see what happens.

[4F4Nam]

Okay. Must be one of those optical delusions. I'm at a loss as to your problem.

Ed

[Parashooter]

The broken and cracked necks are no indication of overpressure, nor is there anything abnormal about the shoulder shape (just perspective and lighting).

Guessing from the pictures, the cases shown were fired in the K31, where the extra chamber width at the shoulder caused more radial stress at the neck/shoulder junction than this inadequately-annealed brass could stand. If some of the failures occurred in the 96/11, it's possible they appeared as axial neck/shoulder cracks rather than the radial and compound failures pictured (thanks to the smaller diameter of the 1911 chamber at the body/shoulder junction).

I'm not sure who makes Frontier-branded brass but suspect it was sourced from Prvi Partizan, a maker with a reputation for variable quality and occasional inadequate final anneal.

[musketshooter]

It appears to me that the cases were not annealed during the forming process If you have more, anneal the necks and try again. The failures are an indication of very brittle brass.