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mrerick · 08-30-2013, 01:00 PM

Greg, the last thing you want to do is put a chamber out of round. That's why an earlier post mentioned using grit and a lathe - to keep the polishing centered.

When a 7.65mm .30 Luger cartridge fires, it pressure peaks at between 28,000 and 30,200 PSI.

It's the job of the cartridge case to seal the chamber during this pressure excursion. After that, brass springs back a thousandth to allow extraction.

If you take things out of round by polishing by hand, it's possible that you'll impact accuracy and could establish areas of imperfect sealing, allowing a higher risk of blowback.

08-30-2013, 01:00 PM	#37
mrerick Super Moderator - Patron LugerForum Life Patron Join Date: Dec 2009 Location: Eastern North Carolina, USA Posts: 3,925 Thanks: 1,377 Thanked 3,140 Times in 1,520 Posts	Greg, the last thing you want to do is put a chamber out of round. That's why an earlier post mentioned using grit and a lathe - to keep the polishing centered. When a 7.65mm .30 Luger cartridge fires, it pressure peaks at between 28,000 and 30,200 PSI. It's the job of the cartridge case to seal the chamber during this pressure excursion. After that, brass springs back a thousandth to allow extraction. If you take things out of round by polishing by hand, it's possible that you'll impact accuracy and could establish areas of imperfect sealing, allowing a higher risk of blowback. __________________ Igitur si vis pacem, para bellum - - Therefore if you want peace, prepare for war.