Curiosity + Too Much Time

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DC_art

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So, I recently loaded a bunch of 155gr plated bullets in line with the Speer and Hornady manuals for their 155 gr HP bullets with 8.6 gr of Power Pistol. Those loads are now waiting for me to install and master my new Hornady collet bullet puller. They were screaming along at over 1300fps. So the curiosity and too much time (after the Honey Do list was done for the day) kicked in. I decided to see how the three manuals I have compared. I plotted each with just their data and got an equation. I then used that equation to generate data for the all the data point and plotted it. The chart is attached. The book starting and max loads are:

Hornady
5.8 gr 1000 fps
8.9 gr 1250 fps

Speer
8.0 gr 1112 fps
9.0 gr 1213 fps

Lyman
7.o gr 942 fps
7.8 gr 1082 fps

Any comments, like on the difference at a given load? Before anyone gives me a hard time about my load know that those loads REALLY put a hurting on the bowling pins!

I'm just looking to see what if anything those far smarter than I have to say.
 

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Hmmmm, not sure what you are wanting here. As far as data goes, it simply tells us what those doing the testing found in their trials. It also gives a suggestion as to where we can start to be safe in our own trials.

The published velocities are what they found in their tests with the gear they were using. Since we are not likely using the same gear, no telling what our results will be. I have never shot over a chrono, and it doesn't really matter much what the velocity is, as long as they perform well, I am happy.

The published data gives us a suggestion as to how fast they might be going.

The differences you see in the charts are due to the different pieces they were shot in primarily, and also the loads themselves. Things besides the amount of powder come into play.
 
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BTW, I knew I forgot something big: This is for 40 S&W. All 3 sources used 4inch barrels. I'm just wondering why the starting and especially the max loads are so different. If, they're going by pressure measurements, my simple mind would expect more consistent results and ranges.
 
That's certainly an interesting chart, but what exactly are you asking or implying? Are you comparing your results with published estimates and results?

GS
 
Do they all have the same OAL listed? If so, maybe the bullets they're using are different in height (i.e one seats deeper than the others).
 
BTW, I knew I forgot something big: This is for 40 S&W. All 3 sources used 4inch barrels. I'm just wondering why the starting and especially the max loads are so different. If, they're going by pressure measurements, my simple mind would expect more consistent results and ranges.
My thinking on this runs along the lines of Zaphar's thinking and question.

Hornady is publishing load data for their bullet and Speer is doing the same for their bullet.

Speer in their loading manual shows a test COL of 1.120" for their 155 grain Gold Dot HP while Hornady shows a test COL of 1.125" for their 155 grain XTP HP. That would be the Speer #12 manual and Hornady #9 manual.

While I can't say it holds true for the .40 Caliber bullets I can show an example of .45 Cal bullets from both manufacturers.

Speer%20Hornady%2045%20ACP.png

Both 230 grain HP bullets but different in their profiles. If we look at the loading manuals they have a different COL and different loads for the same powders (Min & Max). Also different case trims and different primers used to get the results each manufacturer got in their test conditions.

When I use Hornady bullets I use their load data and the same is true for Speer. Additionally start low and work up applies as usual.

Just My Take....
Ron
 
I just expected a little more consistent results, specifically in the range of powder load. That went from 0.8 grain for Lyman to 3.1 grains for Hornady. How do these guys determine their starting loads? Aren't the max loads supposed to be approaching max SAAMI specs?

Just leaves me wondering how the whole process is run.

Art
 
I'm beginning to think the lawyers determine the starting load for Hornady.
 
I just expected a little more consistent results, specifically in the range of powder load. That went from 0.8 grain for Lyman to 3.1 grains for Hornady. How do these guys determine their starting loads? Aren't the max loads supposed to be approaching max SAAMI specs?

Just leaves me wondering how the whole process is run.

Art
We normally do expect a little more consistency but good luck on that note. No matter how hard we try getting the same numbers is a crap shoot and will seldom happen as we try to duplicate the test loads. I attribute it to, beyond my last post, a collection of other variables. Primers, brass, neck tension and the list goes on.

Overall I seldom look at the manufacturers velocity numbers. I use the manual as a guideline and that is about all I use it for. While not as true for my handgun loads, especially semi-automatic loads, when I load rifle I look at my chronograph numbers, through a specific rifle, and my groups. Seldom does my best accuracy come from the hottest loadings I feel I can get away with.

Also, I am a 1911 type. So why is it that I can make ammunition I see as identical and consistent. Shoot that ammunition in one Colt 5" barrel government model and get good consistent velocities, shoot that same ammunition in another Colt 5" barrel government model and get consistent but different velocities? Magic? Maybe gremlins? :) So toss the guns in the variable collection.

Years ago I really got into this. The chronograph is a fun tool. I had the curiosity and time. Then life and work got busy so while the curiosity thrived the time was just not there. Finally retired and next summer I hope to play around a little more.

Ron
 
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I use the manual as a guideline and that is about all I use it for
This gets to be a another crap shoot when you use a vendors bullets who does supply specific load data. Whose book do you start out with. Here you could start out at 5.8, 7.0, or 8.0. Fairly significant spread at this range.
 
As to your last question, I would go to the powder manufacturer.
Not real good at mathematics or science, but I would not presume that there is a linear relationship in the powder weight.
 
I like using powder manufacturer data too. I could care less about bullet difference. Seen those pics of those .45jhp before. What I learned in physics is mass is mass. The weight of the bullet makes MUCH more difference than a couple thousanths of depth! I've set some bullets a little deeper and then set them not as deep and it does not matter unless you are totally maximum on your powder loads.
Keep it simple and start out light. And use heavy bullets for those bowling pins. Thers lots of data for 200gr 40s out there.
 
As stated before, test results will always vary. Fluctuations tolerances/measurements while manufacturing cause the expected variations within the same lot and batch of all materials; powder, primer, case and even bullet.

Measure 10 bullets from the same box and you'll see a pretty decent spread in the length of the bullet. Their weights will all probably fall within .2 grains of each other and the diameter will usually run very consistent, but I see a margin sometimes of +/- .007 (from say .39 - .405) within the same batch of almost all manufactured bullets I have tried; Rainer, Winchester, Remington. Rifle bullets are just as bad even from Sierra and Hornaday.

What would the difference in performance be with a projectile length being .003 longer than spec in a case that is .004 shorter than "max length" . Compared to the next round that is in a case .002 longer than "trim to" length and a bullet that is designed right to spec. Speaking of cases, do cases have the same thickness and fill capacity from one test-round to the next? My guess is we'll find the same (slight) variation from piece to piece. Let's not even get started on barrel heat and atmospheric conditions.

Does anyone actually trim ALL of of their handgun cases before reloading to ensure they are ALL the exact (or as close as possible) length? I tried it once with a batch of 9mm and what I found was the end didn't justify the means. There are FAR to many other variables that outweigh the variation in case length. At least, to justify the "kind" of shooting I do. (Recreational)

These are the kinds of things that drives my OCD bonkers and could lead to quite a data sheet in a design of experiments that would probably drive the recreational shooter (like me) to drink (i have).

Hey, I love reloading and watching the fruit of my labor punch nice groups (patters if its a bad shooting day) into a target. But time to time I am guilty of taking analysis to paralysis....
 
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I would not presume that there is a linear relationship in the powder weight

Certainly there would not be a completely linear relationship, but evidently in this range there is somewhat of one. The Hornady data calculated was within 4 fps of the data in the book. That doesn't say anything to the other data though.

BTW, Alliant's load is 9.0 grains Power Pistol for the 155 gr Speer GDHP.

Art
 
This gets to be a another crap shoot when you use a vendors bullets who does supply specific load data. Whose book do you start out with. Here you could start out at 5.8, 7.0, or 8.0. Fairly significant spread at this range.
While I don't use Power Pistol and my older Speer Manual #12 doesn't include it (wasn't yet available :) ) That is a pretty large disparity between suggested loads.

When I do run into a disparity like that I generally look to Lyman or the powder manufacturer's data and try to derive a start load I feel will not send me and the gun to the promised land. That taking us about full circle back to the crap shoot.

The nice thing if there is one is that once we develop a good load for a specific gun we have it for future reference. Not to say powder doesn't change lot to lot, or brass or primers (the list goes on) but we have something to work from for future loadings.

Keep in mind, most powders can vary lot to lot and even within a lot as can brass, primers and bullets. This can make perfect repeatability like an impossible quest but fortunately from an accuracy point many variables can be a little forgiving.

Just My Take....
Ron
 
I have encountered the same variations when consulting the different load manuals when working up a start load for the same type and weight bullet. As stated here already, I do give the most credence to the powder manufactures data and I pay particular attention to the test barrel length. I have noticed the upper range loads do tend to be in the same ballpark such as the Hornaday 9.0 and the Speer 8.9 you have listed.

I would guess the start loads being lower such as the Lyman data you referenced could account for those who might want a lighter recoil load or merely a range plinker or just the most cost effective load that will work safely in their firearms.
 
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