Split case

[Warrenoliver]

Any ideas on what caused this split? This occurred during load workup and the shot did not sound or feel different from any of the others. Did not have heavy bolt lift or ejector marks.
Rifle: tikka t3 hunter 6.5x55
Hornady brass - 4th firing
Always full length sized
48 gr. Vihta vuori n165
139 gr. Lapua scenar bullet
Federal 210M match primers
Muzzle velocity 2621 for this load.
Photo is after I cleaned it up to check for other cracks. I also used a borescope to check inside the case for signs of case head separation and did not see any.

 

[ShtrRdy]

I would guess it's a weak spot in the brass. Cut the brass in half across the split and you'll be able to see if its thin in that area.

 

[wv270wsm]

Not sure it may just have been a faulty piece of brass . Had almost the same issue a few years ago with my 270 wsm . Had 2 pieces split one on the neck and one down near the case head . First loading on brand new brass. Never had an issue since

 

[MagnumManiac]

Could be a fault caused by the drawing process of the brass, have only seen it once myself.

Cheers.