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mrerick · 06-14-2020, 04:29 PM

Note that the OAL listed for cartridges in reloading guides are for specific bullets (and bullet profiles).

You can't use the same OAL for a round nose bullet as you would for a flat nose one. It will result in the bullet being seated too shallowly in the case, and this can seriously change the ballistics at time of ignition, the jump into the leade and the engagement hesitation delay. This can then change the peak pressure(s) considerably from what was found experimentally in the manual.

Your 9mm Luger round looks seated far shallow into the case. The bullet should never be actually in contact with the leade while chambered. It needs the "jump" across an air gap to gain adequate acceleration prior to the resistance of leade engagement and hesitation as it starts traveling in the rifling.

What reloading manual are you using, and which cartridge / bullet / powder / primer combination?

06-14-2020, 04:29 PM	#2
mrerick Super Moderator - Patron LugerForum Life Patron Join Date: Dec 2009 Location: Eastern North Carolina, USA Posts: 3,900 Thanks: 1,370 Thanked 3,094 Times in 1,503 Posts	Note that the OAL listed for cartridges in reloading guides are for specific bullets (and bullet profiles). You can't use the same OAL for a round nose bullet as you would for a flat nose one. It will result in the bullet being seated too shallowly in the case, and this can seriously change the ballistics at time of ignition, the jump into the leade and the engagement hesitation delay. This can then change the peak pressure(s) considerably from what was found experimentally in the manual. Your 9mm Luger round looks seated far shallow into the case. The bullet should never be actually in contact with the leade while chambered. It needs the "jump" across an air gap to gain adequate acceleration prior to the resistance of leade engagement and hesitation as it starts traveling in the rifling. What reloading manual are you using, and which cartridge / bullet / powder / primer combination? __________________ Igitur si vis pacem, para bellum - - Therefore if you want peace, prepare for war.