Different Gun - Different Velocity

[Ganderite]

The last time I loaded 32 Auto, I used a 75 gr plated bullet and 3.6 gr. of powder. This was 1050 fps and I noted that this was MAx, or over.

So this session, using a 71g plated CamPro, I started with a few loaded at 3.4 gr. Velocity was much lower than expected - only 700 fps. I loaded a bunch at 3.55gr and they were 800fps in my Beretta 1935. The plinker velocity I was looking for. I thought the lower than expected velocity was due to a different bullet and a different lot number of powder.

I found a box of 95 gr cast lead RN bullets, so loaded some of them with 2.5 gr at 835fps in a Savage 1907. A potent load.

I decided to try both loads in a Walther PP. It was eye-opening. The Beretta must have a big bore or something. The PP shot the 71gr at 1040fps (only 807 in the Beretta).

I intended to make 1000 plinker velocity rounds. In the PP they are +P, and probably +P in most of my 32s. The Beretta I used for load development was a bad choice. Bad luck.

I have not chonied ammo in very many of my 32s, so have no idea which ones are "fast" or 'slow".

 

[GRFCal]

Nice collection of pistols. Are those a couple of Stars middle right side of the photo? In my experience (rifles only never had two pistols in the same cartridge at the same time) different gun always meant different velocity but nothing as dramatic %age wise as you have shown.

Interesting post, thanks.

 

[Ganderite]

Nice collection of pistols. Are those a couple of Stars middle right side of the photo? In my experience (rifles only never had two pistols in the same cartridge at the same time) different gun always meant different velocity but nothing as dramatic %age wise as you have shown.

Interesting post, thanks.

Those are a pair of Llamas. they work well. I have some Stars, but they are in 380ACP.

I re-ran the ammo test in an Astra and a Beretta 70. The 71 gr velocity was not so high - about 950 fps.

Now I wonder if the 1040 fps was a gun anomaly (very tight chamber/bore) or a Chrony error. ???

I will test some more pistols.

 

[LordEvilPepper]

i would assume the velocity is primarily effected by the difference in slide weight/ recoil spring stiffness as these are both blow pack pistols.

the berretta is a military action with a very reliable reloading cycle... so it probably has a lighter slide and allows more of the energy to be wasted as the slide starts moving back sooner then the PP

 

[DGY]

Good info, thanks for sharing!