Cartridges are too short

[Dwight Gruber]

There is another pertinent difference between the 7,65 Parabellum cartridge and the DWM 9x19 round (actually, a couple of pertinent differences).

With the too-short 9mm round, the bullets snag on the top edge of the chamber. The 7,65 bullet, being narrower, does not present its ogive to the top of the chamber, so does not get caught up even if the OAL is a fraction shorter.

The original 9x19mm design used a truncated-cone bullet. Although not specifically designed this way for proper feeding, it coincidentally successfully mimics the ogive properties of the 7,65mm round. Some modern Winchester 9mm ball ammunition has a gently truncated-cone bullet.

--Dwight

[Sieger]

Originally Posted by Dwight Gruber

There is another pertinent difference between the 7,65 Parabellum cartridge and the DWM 9x19 round (actually, a couple of pertinent differences).

With the too-short 9mm round, the bullets snag on the top edge of the chamber. The 7,65 bullet, being narrower, does not present its ogive to the top of the chamber, so does not get caught up even if the OAL is a fraction shorter.

The original 9x19mm design used a truncated-cone bullet. Although not specifically designed this way for proper feeding, it coincidentally successfully mimics the ogive properties of the 7,65mm round. Some modern Winchester 9mm ball ammunition has a gently truncated-cone bullet.

--Dwight

Dwight;

As long as I follow the correct procedure in properly determining OAL, I've never experienced jamming with any TC or RN bullet of proper weight and configuration (most typically available brands).

The correct OAL for the RN 9mm bullet is also 1.173 inches, NOT the later derived SAMMI, so often misquoted, 1.169 inches.

For a review, our readers might enjoy reading, in the Reloading Sticky Section, "How to Determine Proper OAL with a New Bullet" as it will answer many of their questions.

Sieger

[Sieger]

Originally Posted by Dwight Gruber

There is another pertinent difference between the 7,65 Parabellum cartridge and the DWM 9x19 round (actually, a couple of pertinent differences).

With the too-short 9mm round, the bullets snag on the top edge of the chamber. The 7,65 bullet, being narrower, does not present its ogive to the top of the chamber, so does not get caught up even if the OAL is a fraction shorter.

The original 9x19mm design used a truncated-cone bullet. Although not specifically designed this way for proper feeding, it coincidentally successfully mimics the ogive properties of the 7,65mm round. Some modern Winchester 9mm ball ammunition has a gently truncated-cone bullet.

--Dwight

Dwight;

Taking a good look at that very angled grip, I think you will find that the cartridges loaded toward the bottom of the eight shot magazine cause the upper most cartridges to cant downwardly. This downward canting is the source of the infamous "Luger Jam".

This is why proper OAL is so critical with this design.

This is true for both the 9mm and the 7.65mm.

Sieger