Question on using data

[goatroper]

Well I have got my reloading bench all setup and ready to go. I have read the ABC’s of reloading twice and read the Lyman Book of pistol and revolver twice also.

But I am still a bit mystified on a certain point.

I am planning to load 45ACP using 230 grain FMJ bullets and Alliant Power Pistol.

The Alliant web site gives one recipe using 8.1 for 916fps
The Lyman book gives starting 6.4 for 775fps and max7.2 for858fps
The Hornady book gives starting 5.6 for700fps and max 7.6 for 900fps
The Sierra book gives starting 5.4 for 700fps and max 7.3 for 900fps
The Speer book gives starting 7.0 for 806fps and max 8.1 for 916fps

Now I understand different test barrels and components, but is this normal to find such different top end or max loads?

I guess the one that puzzles me most is from my first two sources of information I used. Lyman says max is 7.2 and then the maker of the powder says just use 8.1.

Thanks for any help or insight into this matter!!!!

and a photo of my new setup.

[onesonek]

There a number of reasons for the differences, and it's not all that uncommon. Some are more conservative than others for the most part. I tend to reply on those that show their pressures, but not all do.
The main thing to look for, is that bullets are of the same make in the the data as to what you are using,,,,, not always the case or possible either. The reason being is that different mfg's can use core's of different hardness and jacket materials. Of which both can affect pressures drastically. Primers can vary pressures as can brass, but not to the degree of switching bullet makes of the same weight and style.
So what I would do, being I have no experience with the 45ACP, is take all the starting loads and do an avg. and use that for my start, and work up from there to find an accurate load. Depending on what the intended use is, I would likely go an accurate load on the low end over the high end.

Dave

[gyrfalcon]

Well I have got my reloading bench all setup and ready to go. I have read the ABC’s of reloading twice and read the Lyman Book of pistol and revolver twice also.

Twice, and you still have questions? I just bought the ABC's of reloading and I'm very impressed with the amount of information in it, but it seems to be a bit too repetitive for my tastes.

You should buy Lee's reloading manual too... the more data you have the more it starts to make sense, and he also publishes pressure info.

There a number of reasons for the differences, and it's not all that uncommon. Some are more conservative than others for the most part. I tend to reply on those that show their pressures, but not all do...The main thing to look for, is that bullets are of the same make in the the data as to what you are using...I would likely go an accurate load on the low end over the high end.

Ditto to all of your points... besides accuracy if you're just reloading for plinking ammo there is no need to max out on your loads. As long as it cycles and gets out of your barrel you should be alright.

[ex-LT]

The Alliant web site gives one recipe using 8.1 for 916fps
The Lyman book gives starting 6.4 for 775fps and max7.2 for858fps
The Hornady book gives starting 5.6 for700fps and max 7.6 for 900fps
The Sierra book gives starting 5.4 for 700fps and max 7.3 for 900fps
The Speer book gives starting 7.0 for 806fps and max 8.1 for 916fps

IIRC, the Alliant website shows ONLY max loads. To SAFELY use their data, you need to back that off 10% (0.8 gr) -- which puts you about in the middle of the Hornady and Speer manual data -- and work your way up in .1 gr increments, checking for signs of overpressure. Not sure why the Lyman and Sierra books are so low, unless it's due to different bullet profiles.

ETA: forgot to add - nice set up.

[JoeH]

What's your goal for this round? Do you want something soft shooting or do you have a velocity that you want to achieve? Do you have a chronograph?

Start at 5.4 and work up.

[rugersol]

Kinda like Dave, I'd try to correlate from the aggregate.

Ya don't always wanna calculate a fps/gr ... certainly not to come up with a charge for a desired velocity ... but, for correlation, it beats guessing.

I just took the max of each load (ignoring the duplicate, which was most likely copied):

916/8.1 = 113.09
858/7.2 = 119.17
900/7.6 = 118.42
900/7.3 = 123.29

Then I took the average fps/gr of 118.49 and divided that into the average velocity of 893.5 to get a correlated max of 7.5gr for 893.5fps.

Multiply that by 0.9, and ya get a start load of 6.8gr. Again, we can't simply multiply by 118.49 to get the expected velocity ... but if we do, we get 805fps. ... which, if it were accurate, wouldn't be a bad starting target velocity. In all likelihood, your actual velocity may very well be somewhat lower ... albeit, not to a detrimental extent.

If ya wanted to go much slower ... if it was me, I'd probly look into a little faster powder. Based on what's published, I wouldn't be overly concerned 'bout takin' the average of 5.4, 5.6, and 6.4 of 5.8gr. However, if yer gonna wanna shoot a lotta rounds closer to 700fps, yer load-density probly ain't gonna be very good ... at which, yer accuracy may suffer, as well. But I don't use Power Pistol myself ... so that's jest a guess.

[onesonek]

Kinda like Dave, I'd try to correlate from the aggregate.

Ya don't always wanna calculate a fps/gr ... certainly not to come up with a charge for a desired velocity ... but, for correlation, it beats guessing.

I just took the max of each load (ignoring the duplicate, which was most likely copied):

916/8.1 = 113.09
858/7.2 = 119.17
900/7.6 = 118.42
900/7.3 = 123.29

Then I took the average fps/gr of 118.49 and divided that into the average velocity of 893.5 to get a correlated max of 7.5gr for 893.5fps.

Multiply that by 0.9, and ya get a start load of 6.8gr. Again, we can't simply multiply by 118.49 to get the expected velocity ... but if we do, we get 805fps. ... which, if it were accurate, wouldn't be a bad starting target velocity. In all likelihood, your actual velocity may very well be somewhat lower ... albeit, not to a detrimental extent.

If ya wanted to go much slower ... if it was me, I'd probly look into a little faster powder. Based on what's published, I wouldn't be overly concerned 'bout takin' the average of 5.4, 5.6, and 6.4 of 5.8gr. However, if yer gonna wanna shoot a lotta rounds closer to 700fps, yer load-density probly ain't gonna be very good ... at which, yer accuracy may suffer, as well. But I don't use Power Pistol myself ... so that's jest a guess.

Thats interesting, I never ran the numbers like that, but it does show one of two things with out more specific info given in the original post,,,such as barrel length with primer and brass makes.
With those numbers, logic dictates,,,,, if,,,, one assumes the barrel lengths are equal in the test guns, that besides the definate possibility of different components, but also the difference in the test barrels/chambers themselves come into play.
For example,,, I have a custom barrel for the TC Encore in a 9.3x74R. The chamber was cut by EDM to match my dies, which also turned out to be fairly snug to the Norma brass spec's/size. That and Douglas barrels are noted for being fairly tight as well....
Point is, I used a starting load from Nosler as I was using their 250 gr. BT's initially, using R-15.
The very first round was a tad sticky from the alcohol swabbed chamber, (I like dry chambers as it grabs the brass better and reduces back trust). I let another go just to see,,,it was likewise. I didnt bother taking the chrono out and continue.
Back home I pulled the bullets and loaded a starting load of H4350 from the Hodgdon manual of 64 grs. and a mild pressure of 35,000 CUP. Back out to shoot that load, and found the same results,,,sticky.
So staying with that charge weight I went to the slower H-4831 even though it isn't listed, But I knew by being slower the chrarge weight couldn't be any higher in pressure. Well that shot fine with no extraction problems or any other pressure signs. So back to load bench to weigh up a full ramp, that took me up to 68 grs.. Still no extraction problems or pressure signs. I had room for more powder yet, but was very happy the way it was. I did run these over the chrono. My 68 gr load of h-4831 which is max listed for the 4350 @2370 fps and 40,600 CUP,,,was producing 2600 fps shooting 1/4 moa groups. Well beyond the listed velocity listed, yet the gun didnt mind it at all. Now I know my pressure is likely above the specs of the original cartridge with the 9.3, but here again, it's the firearm itself that dictates what max is or is not. As long as my brass life isn't too short, I'm good with it.
The primer pockets are still tight after 5 loadings, so I will stick with it.

Point again is, the firearm will dictate, and as I said before many time,,,manuals are not manuals, but rather guides. That, and the difference in chambers and barrels have a major roll to play in the load.
And then again in some situations,,,,, one can only learn from experience,,as in more barrels I have had OTT edm the chambers, I start lower than manual/guide, with the slowest powders or even slower.
Some things just can't be found in print!

Dave

[Seismic Sam]

Yes, the technique of doing FPS per grain and averaging is something I hadn't seen or thought of before, and just from a caution standpoint I thought I had better point out what could be a flaw in this logic. If you make an assumption about FPS per grain you are implicitly assuming a LINEAR relationship between charge weight and velocity. Unfortunately, that may not be the case, although I would suspect most reloading handbook data is pretty linear, because you don't want somebody to go over the max by a couple tenths of a grain and blow his head off.

Unfortunately, there is the example of John S.'s 45-70 data which did start to dramatically curve upwards at the top of the load range, so counter examples do exist. the good news is that if you are assuming linearity and pick a point below the top of the assumed linear data, your velocity will probably be below what you would expect based on a linear trend. Now, provided this doesn't get you so worked up that your handloads aren't working right and you start loading up max loads to get the &^#$&%#$$#&^^$%$%!!! velocity you want, you're probably going to be okay.

So: Calculating FPS per grain is interesting, but remember that you are assuming a linear relationship between charge weight and velocity, and this may not be true in all cases. The case that could get you seriously hurt is where you caculate a linear line between min and max loads from a handbook, and then go a few tenths of a grain over the max while assuming the velocity (and pressure!!) will go up linearly with charge weight. I can tell you from personal experience that this is NOT the case for 10mm max loads, and a few more tenths can get you a bulged case. Caveat emptor!!

[mitchx3]

Yes, the technique of doing FPS per grain and averaging is something I hadn't seen or thought of before, and just from a caution standpoint I thought I had better point out what could be a flaw in this logic. If you make an assumption about FPS per grain you are implicitly assuming a LINEAR relationship between charge weight and velocity. Unfortunately, that may not be the case, although I would suspect most reloading handbook data is pretty linear, because you don't want somebody to go over the max by a couple tenths of a grain and blow his head off.

Unfortunately, there is the example of John S.'s 45-70 data which did start to dramatically curve upwards at the top of the load range, so counter examples do exist. the good news is that if you are assuming linearity and pick a point below the top of the assumed linear data, your velocity will probably be below what you would expect based on a linear trend. Now, provided this doesn't get you so worked up that your handloads aren't working right and you start loading up max loads to get the &^#$&%#$$#&^^$%$%!!! velocity you want, you're probably going to be okay.

So: Calculating FPS per grain is interesting, but remember that you are assuming a linear relationship between charge weight and velocity, and this may not be true in all cases. The case that could get you seriously hurt is where you caculate a linear line between min and max loads from a handbook, and then go a few tenths of a grain over the max while assuming the velocity (and pressure!!) will go up linearly with charge weight. I can tell you from personal experience that this is NOT the case for 10mm max loads, and a few more tenths can get you a bulged case. Caveat emptor!!

Beyond averaging you could get min/max and a couple points between and do a line of best fit using exponential functions. Wouldn't that satisfy at least a lot of Sam's concerns?

[onesonek]

Yes, the technique of doing FPS per grain and averaging is something I hadn't seen or thought of before, and just from a caution standpoint I thought I had better point out what could be a flaw in this logic. If you make an assumption about FPS per grain you are implicitly assuming a LINEAR relationship between charge weight and velocity. Unfortunately, that may not be the case, although I would suspect most reloading handbook data is pretty linear, because you don't want somebody to go over the max by a couple tenths of a grain and blow his head off.

Unfortunately, there is the example of John S.'s 45-70 data which did start to dramatically curve upwards at the top of the load range, so counter examples do exist. the good news is that if you are assuming linearity and pick a point below the top of the assumed linear data, your velocity will probably be below what you would expect based on a linear trend. Now, provided this doesn't get you so worked up that your handloads aren't working right and you start loading up max loads to get the &^#$&%#$$#&^^$%$%!!! velocity you want, you're probably going to be okay.

So: Calculating FPS per grain is interesting, but remember that you are assuming a linear relationship between charge weight and velocity, and this may not be true in all cases. The case that could get you seriously hurt is where you caculate a linear line between min and max loads from a handbook, and then go a few tenths of a grain over the max while assuming the velocity (and pressure!!) will go up linearly with charge weight. I can tell you from personal experience that this is NOT the case for 10mm max loads, and a few more tenths can get you a bulged case. Caveat emptor!!

In the short of it Sam, I agree that prudence and caution are the first rule of reloading.
I will question the use of linear evalution however, because again, the only way linear comparision can be used if all the loads were set up with exactly the same components and firing system( be it firearm or testing breech and barrel) to form a base line.
Seeing another set of data that has a steeper rise in the pressure line compared with others only shows a difference not a cause. Going outside a certain testing format(set of components), one is most certainly going to see difference's in pressure curves.
If you take that load that was obviously out of linear cuz we still don't know that the components as whole were actually the same between the marlin and ruger loads, and back the testing loads down in the ruger, say starting at 20- 30,000 CUP it don't matter where,. Then increase the charge weights using the same components, I would bet that would be linear also. It's just what ever they used for testing had a steeper pressure line.
Example,,,,, one could take 2 identicle rifles and work up loads using exactly the same components, but unfortunately we wouldnt have expensive pressure testing equipment.( i'm guessing there's a 90% chance they won't max out the same) But you load both up to what the firearm determines is max. (say using casehead expansion for a monitor) yet we find there is there is a difference in the weight of powder charge. One would think they are at the same pressure yet one got there quicker, therefore, it's not linear, because 2 components were different,,,the firearms themselves.
I might be wrong,,,and often enough am , but to me any data between 2-3 or more publications that turns up linear on a graph is coincidence, or they are using the same testing components or maybe even the same testing lab.

[rugersol]

If you make an assumption about FPS per grain you are implicitly assuming a LINEAR relationship between charge weight and velocity.

I tried to make it clear, you wouldn't wanna use fps/gr, to calculate a charge weight, for a desired velocity.

Past that, all I've done is add CONTEXT to a simple average.

Someone else suggested taking the average starting charge-weight. Which might be fine ... but completely ignores the fps each charge weight, was published, to achieve.

All I did, was factor in the published velocity.

Is it 100% reliable? Of course not. But, what is?

It's a guess ... and if the published data is accurate, a damn good one, at that!

... which, is what I thought the OP was askin' for.

Beyond that, I figured if the OP RTFM two times, he got the part where it says some powders may be compressed, whereas others wouldn't react too well. The latter (and not necessarily exclusive of the former) typically exhibiting a non-linear pressure curve. At which, of course if 20gr = 2,000fps, 40gr will most definitely exceed 4,000fps ... or more likely, jest blow up yer gun.

Hell, jest the other day, I sent an email to Accurate on one of their powders ... lookin' fer a charge weight for .338 Marlin. Still no reply. In the meantime, I correlated through case-capacity of 8mm Mauser, and 3100, through .45-70 for my powder of choice ... a range of 3gr. My measure was already set-up for +1.2gr, so I jest left it. Shot a half dozen rounds ... liked 'em so much, I loaded up 'nother 30rd, and shot 'em Saturday ... had one 3-hole group ... didn't measure it yet ... probly under 1/4moa (with a 4x scope and German #4 reticle ). Primers looked great ... easy extraction ... very nice!

Not necessarily somethin' I'd recommend to yer beginnin' reloader ... but ****!, if ya can't rely on only one published load, and more 'n one don't jive ... hell, I figure it's on!

But John S.? ... that dude is one crazy ************!

[onesonek]

If you make an assumption about FPS per grain you are implicitly assuming a LINEAR relationship between charge weight and velocity.

I tried to make it clear, you wouldn't wanna use fps/gr, to calculate a charge weight, for a desired velocity.

Past that, all I've done is add CONTEXT to a simple average.

Someone else suggested taking the average starting charge-weight. Which might be fine ... but completely ignores the fps each charge weight, was published, to achieve.

All I did, was factor in the published velocity.

Is it 100% reliable? Of course not. But, what is?

It's a guess ... and if the published data is accurate, a damn good one, at that!

... which, is what I thought the OP was askin' for.

Beyond that, I figured if the OP RTFM two times, he got the part where it says some powders may be compressed, whereas others wouldn't react too well. The latter (and not necessarily exclusive of the former) typically exhibiting a non-linear pressure curve. At which, of course if 20gr = 2,000fps, 40gr will most definitely exceed 4,000fps ... or more likely, jest blow up yer gun.

Hell, jest the other day, I sent an email to Accurate on one of their powders ... lookin' fer a charge weight for .338 Marlin. Still no reply. In the meantime, I correlated through case-capacity of 8mm Mauser, and 3100, through .45-70 for my powder of choice ... a range of 3gr. My measure was already set-up for +1.2gr, so I jest left it. Shot a half dozen rounds ... liked 'em so much, I loaded up 'nother 30rd, and shot 'em Saturday ... had one 3-hole group ... didn't measure it yet ... probly under 1/4moa (with a 4x scope and German #4 reticle ). Primers looked great ... easy extraction ... very nice!

Not necessarily somethin' I'd recommend to yer beginnin' reloader ... but ****!, if ya can't rely on only one published load, and more 'n one don't jive ... hell, I figure it's on!

But John S.? ... that dude is one crazy ************!

Now that I think about it, I have used that system of running numbers, but more so with pressure data instead of velocity. As in pressure increase per gr. of powder increase. Kinda forgot that when reading your's, and I just did recently it with the .45-70 working up the possible pressures with an inbetween load of hodgdons trapdoor and marlin loads. There, my main concern was match or making sure rather,,, that I had enough pressure for the alloy hardness I was intending to use, and yet stay close to my velocity range.
While most generally I do have a velocity range in mind. My primary concerns when developing a load when data is lacking, are pressure ranges. That's why I turn to those that do show pressure data.
I also have had to do the same with some wildcats, prior to puter programs like Quick Load and Load from a Disk. Before them I used the Powley slides, but there you are limited in powder choices, so one is back to a correlation process of sorts. As you said, not something for the beginner!!!
Pressure concerns come first with accuracy being the goal. Velocity is always 3rd on the list. I can see what you are doing however if pressure data is not available, which it is unfortunate too many manuals don't publish pressure data.
Now I really don't and didn't completely ingore the velocity when I suggested doing a avg. of the starting loads, Just the veloctiy can vary as to what was tested in, and not being given the barrel lengths with the listed loads,,,, velocity became somewhat irrelevant. I was assuming they were all safe and different lengths was the main difference in speed (an error on my part). Not to mention different testing components and individual publisher pressure caps.
But again, without published pressure's backing up the data, one can only guess or assume its safe. We are left in the territory of who the hell knows, without pressure data.

[goatroper]

Just a quick update, ran off some test rounds and as I worked up I found that 7.0 gr of Power Pistol
gave no signs of high pressure and seemed most like the Federal factory stuff I have been shooting.

Thanks for your help in this matter.

[1911fan]

This is one reason I try real hard to cross check several sources with regards to "hotter" cartridges.

When loading the .38 spec. there are several thousand load combo's out there in printed literature and mag articles and the internet etc. So grabbing one book that says X powder and 158 lead's is 4.0 to 6.0 and flipping open one or two other manuals that say 4.2 to 6.2 and 4.1 and 5.9 as their ranges, one is pretty darn sure that loading 5.0 for a plinker load is going to be just fine.

However, when you get up to say, a .357 sig or a .44 mag or even a .40 S&W, and you have one book listing Powder Y at 4.0 to 6.0 and book 2 listing 4.5 to 7.0 and finally Book 3 listing 6.5 to 8.5, one has to be very careful then in matching all of the components as they tested. Same cases, Same primer, same make of bullet, same exact OAL etc, Otherwise things can go south in a hurry.


When loading rifle rounds, I have several .250 savages and .22-250's. Max for each rifle can vary by as much as 4 full grains. I have one Ruger .250 savage that will eat loads with hardly any case expansion, primers with no change in radius, and drop out extraction that will positively lock up any of the 99 savages I have. I think that is the time when some of the extra care is needed in working loads and documenting what you have done.

Likewise, in the .22-250's My remington 700 and savage 112 both like the exact same loads, and shoot them exceptionally well, were as the older 788 Remington really likes its ammo 2 grains or more lighter. When Chrono'd, velocities from the 788 were within a few feet of both the 700 and the 112, even though it was 2 grains lighter. If I push the 788 with the loads the other guns like, accuracy goes to heck, opening up to over MOA, and extraction just starts to get sticky. Likewise, shooting the 788 loads thru the other two and accuracy is not what it is with the "hotter" loads.

[1911fan]

This is one reason I try real hard to cross check several sources with regards to "hotter" cartridges.

When loading the .38 spec. there are several thousand load combo's out there in printed literature and mag articles and the internet etc. So grabbing one book that says X powder and 158 lead's is 4.0 to 6.0 and flipping open one or two other manuals that say 4.2 to 6.2 and 4.1 and 5.9 as their ranges, one is pretty darn sure that loading 5.0 for a plinker load is going to be just fine.

However, when you get up to say, a .357 sig or a .44 mag or even a .40 S&W, and you have one book listing Powder Y at 4.0 to 6.0 and book 2 listing 4.5 to 7.0 and finally Book 3 listing 6.5 to 8.5, one has to be very careful then in matching all of the components as they tested. Same cases, Same primer, same make of bullet, same exact OAL etc, Otherwise things can go south in a hurry.


When loading rifle rounds, I have several .250 savages and .22-250's. Max for each rifle can vary by as much as 4 full grains. I have one Ruger .250 savage that will eat loads with hardly any case expansion, primers with no change in radius, and drop out extraction that will positively lock up any of the 99 savages I have. I think that is the time when some of the extra care is needed in working loads and documenting what you have done.

Likewise, in the .22-250's My remington 700 and savage 112 both like the exact same loads, and shoot them exceptionally well, were as the older 788 Remington really likes its ammo 2 grains or more lighter. When Chrono'd, velocities from the 788 were within a few feet of both the 700 and the 112, even though it was 2 grains lighter. If I push the 788 with the loads the other guns like, accuracy goes to heck, opening up to over MOA, and extraction just starts to get sticky. Likewise, shooting the 788 loads thru the other two and accuracy is not what it is with the "hotter" loads.