Suggestions for adjusting load?

[Paleoman]

Hi,

I've done some 9mm, 125gr Precision Bullet, with an OAL of 1.134"-1.136", using 4.6 gr of CFE Pistol powder. I chrono'ed them and get a velocity of 1006 fps ave for one set of 15 and 1022 fps ave for a second set. The spread was 60.77 and std dev 15.35 for the first and 65.21 and 20.51 for the second set.

On the first batch the average PF was 125.47, and on the second was 127.37.

When making these, I had about 10 out of 300 that didn't totally seat in the gauge all the way - not flush, but not enough that you could see the groove). They fed fine and plunked fine in my Walther PPQ M2. In the past, I did use an OAL of 1.125" and don't recall issues with that, but after some adjustments, this set was with a longer OAL.

I plan on using these at USPSA matches.

• Q) Should I be concerned about the PF, as it is close (on average) to 125 (some were slightly lower)? I'm on the low end with 4.6gr, and can easily go to 4.8gr (have up to 5.2gr).
• Q) For the guage checks, should I use a shorter OAL, play with the crimp (less/more?), or just chalk it up to having mixed cases (all name brands, but was a mix)?
• Q) I'm curious, if I change the OAL shorter does that imply that a lower or higher load would typically be needed? I think when I had 1.125" OAL I was using 5.0gr with same powder and bullet.

Thanks!

 

[Uzi2]

Consistency of the press stroke, and obtaining a factory taper crimp die would be my first two things to look at.

 

[DW357]

I’d only be concerned with PF if you plan on attending sanctioned USPSA matches likes Area 7 next month. They’ll chrono your loads at those matches. Local matches no one checks.

 

[Paleoman]

I’d only be concerned with PF if you plan on attending sanctioned USPSA matches likes Area 7 next month. They’ll chrono your loads at those matches. Local matches no one checks.

Good to know, I'm a beginner, so I'm just looking to have an opportunity to gauge how my training and practice is going in a more stressful situation. Guess I won't worry about it.

 

[Paleoman]

Consistency of the press stroke, and obtaining a factory taper crimp die would be my first two things to look at.

Using a Dillon 650 with the separate crimp die. I did see on some of the strokes I was having a bit of a problem. Seemed like there was unusual amount of drag on the shell plate, so my pull was not smooth, and I was getting a few primers that were not seating well. I loosened the bolt holding down the shell plate, and that seemed to resolve that issue. It looked like the primer hole was lined up with the primer seating pin (or whatever it is called).

It's very possible that the cartridges that didn't gauge well, could have been at the seating or crimping location. I didn't correlate the two.

 

[Uzi2]

Using a Dillon 650 with the separate crimp die. I did see on some of the strokes I was having a bit of a problem. Seemed like there was unusual amount of drag on the shell plate, so my pull was not smooth, and I was getting a few primers that were not seating well. I loosened the bolt holding down the shell plate, and that seemed to resolve that issue. It looked like the primer hole was lined up with the primer seating pin (or whatever it is called).

It's very possible that the cartridges that didn't gauge well, could have been at the seating or crimping location. I didn't correlate the two.

I'd say you found the cause of your issues.

Is your crimp die a "factory crimp" die? Not all dies are the same. A factory crimp die will give you better ammo from my
9mm reloading experience.

I also use all Dillon dies and no complaints with them at all.

 

[SJan]

Standard deviation of 15 is a little high, 20 is too high, I would not be happy with that.
Like others said, use a consistent handle pull to get consistent powder drops.

For USPSA minor PF, 130-132 should be your goal. Yes, nobody checks at locals, but you don't want to be the guy whos ammo cant knock down a popper that is set a bit heavy, and more often than not, you will experience better SD (and accuracy, they are related after all) with a slightly hotter load.

 

[Paleoman]

I'd say you found the cause of your issues.

Is your crimp die a "factory crimp" die? Not all dies are the same. A factory crimp die will give you better ammo from my
9mm reloading experience.

I also use all Dillon dies and no complaints with them at all.

Yes, all Dillion dies.

 

[Paleoman]

Standard deviation of 15 is a little high, 20 is too high, I would not be happy with that.
Like others said, use a consistent handle pull to get consistent powder drops.

For USPSA minor PF, 130-132 should be your goal. Yes, nobody checks at locals, but you don't want to be the guy whos ammo cant knock down a popper that is set a bit heavy, and more often than not, you will experience better SD (and accuracy, they are related after all) with a slightly hotter load.

Good to know. I’ll try to adjust the load. What std dev do you look for typically?

 

[Uzi2]

Yes, all Dillion dies.

You won't be disappointed then, they are great dies.

 

[Paleoman]

Well, I wanted to just update the load from 4.6gr to 4.8gr, as an earlier test showed I was getting around 133 for PF for 4.8gr. However, I ran out of CCI primers and had to switch to Fiocchi. I created a batch of cartridges with these primers and 4.8gr, and I see a PF around 121.

I'm assuming that is the reason for the difference, as all other things are the same (OAL, bullets, technique).

Does that sound reasonable, that one could see a PF difference of ~12 with a change in small pistol primer?

When I looked up CFE Pistol data, for use with Precision Bullets 125gr, I used the 125gr LCN 0.356" dia data. Which for a COL of 1.125 it had start load of 4.4 (v=1041) and max of 5.0 and a max velocity of 1156 fps with a 4" barrel.

I have a 4" barrel and 3.5" barrel in 9mm.

Now, I'm at COL 1.132" vs 1.125", but I clearly am getting lower velocity than the load data shows. With 5.8gr, I see PF=121, and V average 969.74 fps with one set and 974.8 fps with another set I tested.

Should I slowly move up to 5.0, 5.1,... to see if I can get a higher PF and keep velocity under 1156 fps?

Should I consider going to 1.125" OAL (that does work in my barrels too)?

If I do that, with the shorter OAL result in higher velocities/pressures?
IOW would I be able to then work up from 4.4gr and get a minor PF w/o exceeding the max load data?

Suggestions?