Thread: Pressure estimate for stiff extraction on new brass

If you have worked up loads in new unfired brass to the onset of stiff extraction as a result of case lengthening from that first firing could you please let me know what you estimated the peak pressure to have been ?

Originally Posted by Puffin

If you have worked up loads in new unfired brass to the onset of stiff extraction as a result of case lengthening from that first firing could you please let me know what you estimated the peak pressure to have been ?

Too much

Which cartridge, powder, projectile weight ?

Interest question only. Given the need to bump shoulders back after progressive expansion over several firings, I wondered what it would take to get the same result in one go? 65kPSI peak? 70kPSI ? I haven't recorded this in the past being more interested in what the primer pockets were doing and imagine it is more dependent on the action type than the brass so that info would be relevant.

If you managed it with a single firing from new I would say the brass would be shagged.

New brass is more elastic/softer than fired brass, as it get fired more & more it gets harder & harder.

This makes it less likely to shrink back after firing causing extraction issues/tight bolt lift.