Case Head Exits Rifle

[ireload2]

This is an interesting thread. I have 2 comments to add.
A friend of mine had one of the 7mm RRBs. He loaded and fired a single round which blew the breech open. The expanded case was left in the barrel and the primer was impaled on the firing pin in the open the breech block. He took his damaged case back to the gun shop and they produced a 7X57 case they had fired that looked normal. I know the shop well. They are honest but not particularly special gunsmiths.
My friend checked his chamber with a cast and showed it to me. The casting showed the chamber had a slightly shorter neck and sharper shoulder than a normal 7X57 case.
When his cartridge was fired he theorized that the heavy hammer blow drove the case mouth in to the throat causing the high pressure and pierced primer. The pierced primer blew the hammer back and the residual pressure opened the breech block. This may offer a clue to how the breech block opens. A high pressure gas leak may be able to blow the hammer back. It sure blew his open though his primer was pierced to enable it.

In regard to oiled cases. I had read of lightly oiled brass fire forming and stretching less and I began trying it with a 40-65 High Wall. This is low pressure ammo in a massively strong action. The case fire formed well and there were no issues. Next I tried a CZ 527 in .22 Hornet. Then reformed .303 WW and R-P brass in a 6.5X53R Dutch M95 Steyr Mannlicher rifle. The cases fire formed perfectly. Since then I have made it a practice wipe a very thin film of oil on each case as I fire form new brass. All my experience with this had been positive.
I don't plan using this for normal shooting of fire formed brass in a rigid bolt action. For this application it only slows down shooting as my existing brass life is nearly infinite with failures being neck or body splits. I will definitely use this technique to prolong case life in the springy Lee-Enfield rifles and reduce the extraction load on my Hakim extractor.