Zero 9MM 125 Grain JHP and IMR 700X Chrono Questions

[Ghost In The Fog]

Hi everyone-
I have a general question about using a chronograph.
I have my loads dialed in and working perfect. I have shot just under 3,000 of the Zeros and just received 2,000 more. I just ordered a chrono and hope to be able to take my reloading to a more exact level.

I am thinking my loads may be slightly on the light side. I want to make sure I am able to make IDPA power factor as well as maximize my reloads. I shoot at a local club that doesn't check power factor. I don't by any means want to push my loads to the limit, I just want a good, solid load.
My question is this....
After I run bullets thru the chrono and get some solid readings when I go to adjust my loads, up or down is it better to:

A: Adjust overall length? (See below)
B: Adjust powder charge?
C: Both?

I am talking minor changes. Right now my COL is 1.100 and I am loading 3.9 to 4.0 Gr. of 700X and have perfect results.
I am hoping that NO changes are necessary that I am at power factor and I am at 1,000 FPS

At 1.075 my G34 FTF's and max COL based on my "Push Test" is 1.178 for my G34 and 1.127 for my G19. My Sub 2000 likes anything over 1.075.
So- staying within those COL's and I attempt to adjust up or down, where is the best starting point?
Change charge +-1 and adjust COL .001?

I do understand their is no exact answer, but I am asking in advance to get a feel for what you all do and how I want to proceed from here.

Thanks for you help.

 

[berettaprofessor]

Sorry, this is not much help, but why not wait until you know whether or not there is a problem before wasting energy about how to fix it?

 

[rfwobbly]

Your OAL is already plenty short. I'd recommend changing only the powder.

1.100 to 1.110 is a good OAL for that bullet, and you're right there.

 

[Ghost In The Fog]

Thank you. I appreciate your input.

 

[ArchAngelCD]

Where did you get those charge weights? According to Hodgdon you are .4gr over their Max. On the other hand Lyman says you can go as high as 4.2gr under that bullet. With a shorter OAL than you are using they report only 1022fps with a charge of 4.2gr. There is no way for you to generate 1000 fps with that powder and bullet in your handgun. You are going to have to change powders, go lighter on the bullet. 700x is a fast powder and I feel you are asking it to do too much.

In general you do not use OAL to change pressures/velocity in a round. OAL is used to make the ammo reliability feed in your handgun.

 

[edleit]

As previously stated, COL will drive reliability of feed/function. Expecting to be able to make a COL change in increments as small as .001" is asking a lot of your process and components. Unless the projectiles are consistent in length and profile you are going to experience variations due to the difference in contact location at the interface of the bullet and seating die. I've seen wider fluctuation in seating depth with bare cast lead than plated or jacketed bullets.

 

[hdwhit]

Just remember, when comparing velocities in the published manuals to those reported by a chronograph that the components, loads and test gun mst be identical if there is an expectation that the results will be identical. For example, if the test barrel was 5 inches long and the subject gun had a 3.15 inch barrel, the velocities will be lower.

In my opinion, a chronograph is useful for verifying the consistency of one's reloading equipment and procedures and identifying problems with consistently anomolously high or low velocities.

 

[rfwobbly]

Mr Fog -
You talk about consistency, but I don't understand how you get it. Not a criticism, but clarification for me. Could you just explain 2 things....

@ 700X is great, but also one of the worst metering powders out there. Are you weighing each load or metering? I would think a better metering powder would serve you better.

@ The Zero HP (or really any HP) is hard to seat consistently. You either smash the tip and allow the base position to wander, which allows the volume under the bullet to vary. Or you seat by pushing on the ogive, which can introduce its own variations without a good fitting seating anvil. Just wondering which you use ?

Trying to understand.

 

[Ghost In The Fog]

Mr Fog -
You talk about consistency, but I don't understand how you get it. Not a criticism, but clarification for me. Could you just explain 2 things....

@ 700X is great, but also one of the worst metering powders out there. Are you weighing each load or metering? I would think a better metering powder would serve you better.

@ The Zero HP (or really any HP) is hard to seat consistently. You either smash the tip and allow the base position to wander, which allows the volume under the bullet to vary. Or you seat by pushing on the ogive, which can introduce its own variations without a good fitting seating anvil. Just wondering which you use ?

Trying to understand.

I missed this message and wanted to reply because you ask some very valid questions. I have learned a lot in the last 2 years of reloading. I still have only scratched the surface and have a long way to go.
After many pounds of 700X, and I still have 4 left, I have done a lot of research and changed powders. I am now using Ramshot Silhouette based on reviews and how well it is supposed to meter.
700X is a very good powder but it meters horribly for me. I use a Lee Classic Turret with the Autodrum I will have .4 to .5 Gr. swings in charge weights.

In answer to your first question, I both meter and then weigh each and every charge when I am figuring out a load. After I have my load data where I want it and begin more of a production sequence, when I am comfortable with how consistent my equipment is working on a given day I stop weighing every round. I became really good at visually seeing the difference in charge weights and dumping the charge and recharging when it didn't look right. I have an LED light on my press and I look at EVERY single charge without exception and variations became easy to see. EXCEPT- 700X is weird sometimes. Some charges are small, tight and dense looking and weigh 4.2 Gr. and others are fluffy, have weird colored flakes and fill up more of the case and weigh in at 3.8 Gr. I got really tired of dealing with the inconsistent metering of 700X and have switched to Ramshot Silhouette.

Question 2- One of the areas I have learned the most about is (and I hate to use the word again) consistency as far as COL goes. When I am trying new load recipes I have gone as far separating brass by head stamp, then by measured length and then by weight and then loading and tracking that data. What a freakin headache and more times than not end up more confused than before I started. What I have found is that yes, it does minimize variations but still there are variations. Albeit slight. When I reach in and grab a handful of mixed range brass and go all willy nilly the differences in COL are .020 at most. I am aiming for 1.100 and get 1.116 on the high end and 1.096 on the low with the majority coming it pretty dag gum close to the 1.100 to the 1.105 range.
In my experience, I have found that once you have your load dialed in, it all doesn't matter. I have spent hours worrying, thinking, and stressing over details that make no real difference. So far, all of my HP's have seated just fine and have given me no trouble. But thank you kind Sir for adding another thing to now worry about. LOL. Kidding of course.
It frustrates me greatly to know how dangerous this "hobby" can be and their is no exact formula.

What I do know and can pass along from my experience is to find out about and do the plunk test as well as the push test. The push test to me was the beginning of understanding all of this. Once I found out that COL didn't mean a hill of beans after determining what COL works in my gun I felt so much better. That was such a mystery and I thought I was going to blow myself up if I had the wrong COL/COAL. Please know that I am kidding about the hill of beans- but that was a huge milestone for me. (Is there a huge milestone? Aren't all milestones huge) Whatevs. To do this properly, you must have a chronograph, or access to one. Find a good load and dial it in from there using your chronograph.

I want to thank you rfwobbly, and all of the good people here for helping to make me begin to understand all of this. It has taken a while and I have a long way to go but I am feeling more confident every day because of people like you and the willingness to help and share information.

 

[ny32182]

Some comments if you are loading for IDPA or other action pistol games:

1) You don't need hyper consistent ammo. Mixed brass is fine. Pick an OAL that feeds in your gun and leave it. You will get better from practicing/shooting, not from spending hours on end chasing some minor element of consistency in your ammo. If it feeds, goes bang, and goes where you point it, it is time to stop worry about the ammo and go practice. It sounds like you are kind of onto this fact now.

2) I DON'T KNOW ANYTHING SPECIFIC about either of your powders, so if you are over a book max load, you could be still plenty safe, or there is a chance you could be in a danger zone; it is hard to say without drawing on the experience of others, unless you really just want to risk your gun finding out yourself. If you are over a book max and still need more velocity, you might consider switching powders (again?)

3) If you are shooting major matches where they are chronoing, load to 135 power factor. Weather changes, chronos are not all exactly the same; your gun won't chrono exactly the same with a dirty vs. clean barrel... etc etc. There are a million variables that can change the exact number you will read at any given time. Loading to 135 is enough to account for these variables. If you are loading to 130 or below, eventually you will get bitten when a bad set of circumstances stacks against you, and you will go sub-minor. That is no fun if it happens at a match that you have hundreds of dollars and vacation time invested in attending.