Heym is tough
Using a .30-06 calculated according to Hartmut Brömels QuickLoadat 10,000 bar peak gas pressure the following experimental setup was used to fire a Heym SR30N straight-pull repeating rifle and the effects of this excess force photographed. Although the bolt did not withstand the force unharmed, even with this amount of force the bolt was not ejected to the back into the shooter’s face
Experimental setup. The weapon is triggered remotely, just to be safe…
Oh boy! The cartridge melted under the pressure. The primer is now non-existent!
Nonetheless, the bolt was not exactly able to withstand the pressure without bursting or coming open.
The inside of the bolt appears somewhat intact after the excessive load.
Well then. Even steel will give way. The high-tensile powder plumes shattered the extractor into pieces and ripped it through the relief hole. Although the pressure bent the chamber, it wasn’t able to tear or open it.
The .30-06 Springfield cartridge was not originally a belted case; butafter being violated like this, it was.
Where primeval forces act…
Brass melts from about 6,000 bar, which we quite obviously exceeded.
There must be a way to break this thing. At the target 10,000 bar the cartridge didn’t bring enough pressure to burst. Gun powder in rifle cartridges works wonders. So quick, up the target pressure to 10,700 bar and pull the trigger…
Well, the primer was originally just pushed inward, but was now trying to get out. And that secondary air, tsk, tsk…
Dammit. This looks like a cheap moped draw-key transmission! At least all the parts are still in place. At an attempted 10,700 bar Ithink that’s pretty good!
However, I don’t see anything that resembles the extractor where itshould be in the notch; maybe some cartridge remains!
Naughty little beggar! No cartridge left, but there are some imprints of the markings! The excess pressure escaped through the extractor chamber,l imiting the peak pressure. My goodness, the shell in front of the breech as relief valve. What a cheap solution!
Yes, here it is again! The hole in the cartridge which the most dangerous portion of the pressure released through without opening the bolt and ejecting it to the back. Wonderful!
A beautiful excess pressure relief primer in front of the breech, just beautiful!
Reloader heed: THAT cartridge is junk! So is the extractor and spring. The Heym SR 30 N merely resulting in blown through casing and deformity instead of opening and blowing the bolt into the shooter’s face at an attainable 10,700 bar of peak gas pressure is actually quite remarkable. Hats off to the designer, Peter Fortner!