06-18-2011, 01:32 AM
Greg,
That's a sure way to jam your chamber up. The reason is that fired brass has expanded with tens of thousands of PSI to literally form it to your chamber-not just the perceived shape of your chamber, but all the microscopic crevices along the chamber surface as well. When this expansion occurs, after the peak is reached, and as the pressure curve spikes back downwards, the molecular memory of the brass attempts to re-orient itself to its position before being expanded, but only contracts a little since that memory has been almost entirely erased by the intensity of 50,000 + PSI.
When the brass is still hot and contracting on a semi-auto, it is easier to be extracted, which is where dwell time comes into play for gas-operated weapons, and delayed blowback on others. It is also why military rifles and machineguns have a chrome-lined chamber, to provide more Rockwell hardness and a smooth texture to facilitate the extraction. (They also help prevent corrosion from the elements.)
Taking a cold piece of fired brass and forcing it into your chamber will get it stuck nice and good, usually requiring removal with significant force, even if your extractor is strong enough to handle the task.
In short, I don't recommend doing it. Sized brass will drop in just fine, provided your chamber and sizing die like each other-at least this has been my experience.
LRRPF52
That's a sure way to jam your chamber up. The reason is that fired brass has expanded with tens of thousands of PSI to literally form it to your chamber-not just the perceived shape of your chamber, but all the microscopic crevices along the chamber surface as well. When this expansion occurs, after the peak is reached, and as the pressure curve spikes back downwards, the molecular memory of the brass attempts to re-orient itself to its position before being expanded, but only contracts a little since that memory has been almost entirely erased by the intensity of 50,000 + PSI.
When the brass is still hot and contracting on a semi-auto, it is easier to be extracted, which is where dwell time comes into play for gas-operated weapons, and delayed blowback on others. It is also why military rifles and machineguns have a chrome-lined chamber, to provide more Rockwell hardness and a smooth texture to facilitate the extraction. (They also help prevent corrosion from the elements.)
Taking a cold piece of fired brass and forcing it into your chamber will get it stuck nice and good, usually requiring removal with significant force, even if your extractor is strong enough to handle the task.
In short, I don't recommend doing it. Sized brass will drop in just fine, provided your chamber and sizing die like each other-at least this has been my experience.
LRRPF52