Observation on Parabellum ammo

some_finn · 06-29-2006, 12:10 PM

Just wondering if anyone else has noticed this.

I was reloading 7.65 Parabellum ammo and had trouble getting my pistol to cycle.
First of all, Fiocchi wouldn't work, it seemed to be too mild (wouldn't cycle all the way). Velocity was about 325 m/s (1065 fps).
First I tried a 6 gram (91gr) bullet with Vihtavuori N320, a fastish pistol powder.
I had to keep adding powder until I got a velocity of about 350 m/s (1150 fps) before the gun started to work properly.
But then I tried Vihtavuori 3N37 powder, which is their second slowest. With this powder I only had to load to a velocity of about 330 m/s (1080 fps) to get the gun to cycle 100 reliably.

So it would appear that the pistol prefers slower powders. I guess this has something to do with the internal ballistics (pressure curve) and the way the action works.

I wonder if this "preferance" is a phenomenom known to other people, and if my observation is even valid or just some strange fluke into which I'm reading too much.

If this "slow powder preferance" is a genuine phenomenom, it might explain at least to a degree why Parabellums are regarded as such "finicky" guns in terms of ammunition.

For 9mm guns, some people recommend ammo with 8g bullets instead of 7.5 but I'm not convinced this is a real issue unless the load is "borderline" in other regards.
Also a myth seems to live in the US that Parabellums need hot ammo to work properly. This is of course quite silly, as the original 9mm load was much milder than any modern commercial ammo.

But the assumed preference for slow powders might go some way to explain why some ammo works better than some, even though there shouldn't be a big difference in the claimed performance.

What do you think?

06-29-2006, 12:10 PM	#1
some_finn User Join Date: Nov 2005 Location: Finland Posts: 20 Thanks: 0 Thanked 0 Times in 0 Posts	Observation on Parabellum ammo Just wondering if anyone else has noticed this. I was reloading 7.65 Parabellum ammo and had trouble getting my pistol to cycle. First of all, Fiocchi wouldn't work, it seemed to be too mild (wouldn't cycle all the way). Velocity was about 325 m/s (1065 fps). First I tried a 6 gram (91gr) bullet with Vihtavuori N320, a fastish pistol powder. I had to keep adding powder until I got a velocity of about 350 m/s (1150 fps) before the gun started to work properly. But then I tried Vihtavuori 3N37 powder, which is their second slowest. With this powder I only had to load to a velocity of about 330 m/s (1080 fps) to get the gun to cycle 100 reliably. So it would appear that the pistol prefers slower powders. I guess this has something to do with the internal ballistics (pressure curve) and the way the action works. I wonder if this "preferance" is a phenomenom known to other people, and if my observation is even valid or just some strange fluke into which I'm reading too much. If this "slow powder preferance" is a genuine phenomenom, it might explain at least to a degree why Parabellums are regarded as such "finicky" guns in terms of ammunition. For 9mm guns, some people recommend ammo with 8g bullets instead of 7.5 but I'm not convinced this is a real issue unless the load is "borderline" in other regards. Also a myth seems to live in the US that Parabellums need hot ammo to work properly. This is of course quite silly, as the original 9mm load was much milder than any modern commercial ammo. But the assumed preference for slow powders might go some way to explain why some ammo works better than some, even though there shouldn't be a big difference in the claimed performance. What do you think?