Questionable reloading data from respectable sources - anyone else have similar problems ?

[Tisto]

To start this off, I should tell you that I have been reloading for a LONG time. A VERY LONG time. More than 35 years, in fact. That being said, I don't claim to know everything, and I still find myself wondering why things just don't seem to add up.

Case in point :
I have finally started to load the .300 AAC Blackout. I have no less than 6 respectable sources of data for this cartridge. Hornady, Speer, Nosler, Sierra, Hodgdon/IMR/Winchester powders, Western powders ( Accurate/Ramshot ), and a few more as well. After studying all the data sources I have, I have come up with 5 different bullet/powder combinations I think will produce the results I'm looking for. 3 of these combinations involved what I will classify as "light" bullets, and used Hodgdon Li'l Gun powder. The other 2 "heavy" bullets used Accurate 1680 powder.

Today I went to the range equipped with the LabRadar chronograph, and 10 of each of these carefully constructed test loads. Today's mission was more about making sure there were no pressure problems and establishing a baseline of velocities to compare. First, I shot 10 rounds of FACTORY ammunition to establish an average velocity. Then, 10 rounds of my comparable handloads. I did this with each bullet weight. ( you with me so far ? )

The light bullets ( 110, 125, & 135 gr ) with Li'l Gun showed no issues at this point, however having used Li'l Gun previously, I'm aware that it has a tendency to go from "no problems" to signs of high pressure ( flattened and cratered primers, possibly worse ) very quickly, sometimes in as little as 1/2 gr. Therefore, I will proceed with load development with these.

Here's where I run into problems. The heavy bullets ( 150 & 190 gr ) with A1680 load data is all over the place. That in and of itself, I could deal with. The problem I'm having is that ALL of it is impossibly wrong ! Here's what I mean A1680 under 150 gr bullet: ( Sierra HPBT Matchking ) [ disclaimer: this is not the EXACT bullet I'm loading, but is very close ]
Source : Western powder - start load 19.4 gr @ 1895 fps. Max load 21.6 gr @ 2086 fps.
Source : Hornady 10th edition - start load 15.4 gr @ 1500 fps. Max load 22.0 gr @ 2050 fps.

Not a whole lot of issues yet...until you realize that a sized and properly trimmed to length case cannot possibly hold that amount of powder and still seat a bullet. A case will hold 20.0 gr of A1680 and be able to compress it enough to seat a flat base bullet to the bottom of the neck. A1680 is a VERY fine spherical powder which fills the case tightly, and leaves very little room to compress it. In testing, with a 150 gr bullet, I found that I could fit no more than 20.0 gr and that was heavily compressed.

Wait, it gets worse. With a 190 gr bullet and A1680 the problem is even more pronounced. Data for a 190 is not shown from Western powders, but one can make a reasonable assumption that it would fall between the next lower and next higher data. Thus, for comparison, start load for a 175 gr bullet is 17.7gr @ 1637 fps. Max load is 19.7gr @ 1801fps. And for a 210 gr bullet, it is 12.9gr @ 1308 fps. and max load is 14.4gr @ 1458 fps.
Hornady data for a 190 is as follows: start 12.9gr @ 1200 fps, and max is 17.8 gr @ 1650 fps.
Once again, in testing, I find that I can fit no more than 15.5 gr under a 190 gr bullet and still be able to seat it. I know that 2.3 gr doesn't seem like very much, but how the hell does Hornady come up with these numbers ? Talk about putting 10 pounds of shit in a 5 pound bag....!!

Ok, if you've read this far and actually understand what I'm trying to say, tell me where I F'ed up.


For the record, All test loads shot today were well below any Max load data. Li'l gun powders produced velocities higher than expected given the short (12") barrel, but showed a wide standard deviation in velocities. Accurate 1680 produced velocities perhaps slightly higher than expected, but the standard deviation was exceptional. The 10 shot group of 150 gr bullets producer a SD of only 29 fps. The 9 shot group ( chrono didn't capture 1 round ) of 190 's produced a SD of 16 fps.

Thoughts ?

 

[Tisto]

I should add that I see the same thing happening with the light bullets and Li'l Gun. The data from Hodgdon shows a much higher charge weight than can possibly fit in the case. Data from Hornady and Nosler is more in line with reality here, but I haven't gone to the trouble of seeing just how much a case will hold of this powder yet.

 

[Darth]

What is your Trim To Length?

 

[Tisto]

All the brass I have is once fired, and headstamped as .300 Blackout. There are no .223 / 5.56 formed cases. It has all been trimmed to 1.359" some data shows a trim-to length of 1.363". Still, .005" won't make enough difference to fit as much powder as the data suggests is possible. With Li'l Gun, I suspect I will find signs of pressure well before I get anywhere near max loads listed in Hidgdon data. Accurate 1680 is much more foregiving. I'm likely to try the light bullets with CFE BLACK. That powder shows very low pressures in comparison, with only slightly lower velocities.

 

[meketrefe]

Hi Tisto.
sorry you are having problem with the BO.
The problem with the whisper/BO is that it was originally designed and intended for subsonic work only and with average accuracy due to the neck/free-bore situation.
Since the Whisper was rebranded and marketed as an internet sensation, people started to publish all sort of inaccurate data, some even impossible loads according to quick-load and other internal ballistics calculations.
AA1680 is a great powder for straight wall cartridges and bullets on the heavy-for-caliber side but with the limit capacity of the Whisper/BO one should keep expectations modest.
Why hornady would list the wrong information? I don't know but I found out every source you mentioned has mistakes. Even the lymans manual makes many mistakes in several popular rounds like the 6.8. The writers are a not that knowledgeable IMO.
Then the powder manufactures look like the loads are written by their lawyers since they do not want to touch hot pressures and why they also tend to be unspecific to protect their arses.
In reality if we want to know the precise measures they would find attributes clearly listed like brass brand, batch and year. The powder brand and year and the bullet brand and model along with the barrel maker, chamber spec/reamer and type of rifling of the test barrels. Also temperature, humidity, etc.. All those factors make a difference in the speed and pressure. Some bullet makers are more accurate with the ones they test but they do not test every cartrige so they copy from somewhere else and might not even run it by the internal ballistics calculator
or research if powders have shown changes and they do sometimes.
But even with all those considerations there is no room in such small case to account for a 2grain difference of 1680 no matter how well is shaken to stack the powder.
So bottom line, settle with more modest realistic numbers and forget about what the internet says. you are a seasoned reloader and know the drill of following a strict test protocol and empirical method.
Lil'gun is good powder too but it is fast and can spike on you quickly not just by introducing grain but harder bullets of the same weight (thicker jackets or core) or by being slightly wider even if it is just 1/2 mil or a combination of those factors in otherwise pretty similar looking bullets .
So the best thing is with new bullets or brass always one needs to come back down as you probably know.
I used H110 that works great with lither bullets and other cartriges but more predictable as lil gun.

Again where the whisper works best is with subsonic and subsonic dedicated gun.

The spreads will be a constant battle but it can be done with lots of care to detail. Not the most friendly round to reload that is for sure.

I don't shoot the whisper much since it has never been that great and with the subsonic my best loads are expensive match bullets so
I save them for the calibers that can do something with them like the winmag and 308.

I hope this helps. good luck.

 

[Tisto]

My expectations are reasonable. I have a very good idea of what I might get out of this cartridge and a 12" barrel, both in accuracy and power. What I don't get is how Western powder says it's possible to fit 21.6 gr of A1680 under a typical 150, or how Hornady says that 17.8 gr will fit under a 190. I haven't tried it yet, but Hodgdon tells me that you can fit 21.0 gr of Li'l Gun under a 125....I'm calling bullshit on that ! Given the loads I tested today with Li'l Gun and the chronograph results , I will hit max safe pressures well before I get anywhere near max listed data.

I fully understand that there are an almost infinite number of variables to deal with. The one I'm concerned with at this moment happens to be the physical properties of volume.

As far as the light bullets, factory ammo performs about as well as may be expected. When the bullets get heavy is where real gains should be able to be had. Factory ammo with 180 and heavier bullets is all subsonic. Since this gun is not suppressed, there is no reason not to kick these bullets up closer to their potential velocities. Every book I have says that a 190 gr bullet and 1500 fps shouls be easily obtainable. Many books are showing quite a bit higher as possible. I just don't see it going that way if the most you can fit in a case is only half way between start and max loads.

As far as DATA from the internet, I don't use any of it. If it doesn't come directly from a reputable source, I ignore it. I have no interest in what some guy says that his best friend's cousin's great uncle loads. Just like I don't shoot anyone else's reloads.

Data always has and always will have discrepancies from one source to another, just as all of those sources have mistakes. It comes with the territory. Reloading is as much science as it is art, and much of it is uncharted. The data sources are there to provide guidance. To keep you from loosing fingers, or to prevent more catastrophic accidents.

 

[meketrefe]

My expectations are reasonable. .... The data sources are there to provide guidance. To keep you from loosing fingers, or to prevent more catastrophic accidents.

Tisto, that is the right approach.

What I was saying is that even those considered "reputable" sources are full of mistakes and why it makes books like lymans book
a waste of dollars and obsolete. So the best is what you are doing taking several sources to get an idea and then build
from there. Some articles in reputable magazines even compared BO loads to be in the same range and even superior
to the 7.62x39 and the 5.56 that we know is a fantasy. ...or they pick and choose what the want to compare. All BS.

If you have any specific powder or bullet you want to model I can check in my data (and I have a lot first hand) or I can run it by
quick-load and other tool I built so I can give you estimates of max loads, pressures and such.
Over the years I found between quick-loads and my software is the most reliable internal ballistics prediction I could get
and helped me design several wildcats for LR and hunting.

Still it doesn't mean that is perfect and I always compare to other data sources but it is a more approximate measure on average.

I have not reloaded the whisper for a while. I got it well before it was rebranded as BO internet marketing sensation and shot it
for a while but if you want I can take several brass makes and give you the H2O spread and the max possible load I can put in them.

It seems to me that you are right about Hornady and those sources and it is a mistake like many other loads so don't even
count on that data.

Don't loose patience. The BO is a hit and miss situation and tricky to make it work right but eventually one could get some decent
loads. Accuracy is never going to be super consistent though in terms of repeatability but normally that is not the goal with this.

 

[Tisto]

Update:
As suspected, I ran into definate signs of pressures being too high with Li'l Gun, and I was nowhere near any max load data. Found this to be an issue with 110, 125 & 135 gr. bullets. I may still play with these combinations, but doing so carefully BELOW any load data I have listed.

Today I tried CFE BLACK with 110, 125, 135 & 150 (2 types ) gr. bullets. Every starting load listed wound up being a compressed load. The chronograph confirmed what the load data suggested, namely that the velocities produced were on the very slow end of the scale. It also showed that the powder was exceptionally consistant, with the standard deviation being 16.8 , 5.7 , 24.5 , 5.6 , and 8.8 FPS [ each group was 10 rounds ] There were no signs of high pressure at all, but all the load data shows this powder as being the lowest pressure of all powders listed, so it was not surprising. For target work I think CFE BLACK is a wonderful choice, but it probably won't be my "go-to" when it comes to loads designed for animals or defense.

 

[Mosinitis]

Load development is so overrated. Find a recommended load from people who use this caliber for hunting or competition. Make adjustments off of it if needed. Why reinvent the wheel?

 

[squib]

Load development is so overrated. Find a recommended load from people who use this caliber for hunting or competition. Make adjustments off of it if needed. Why reinvent the wheel?

I agree, the best part of loade development is when your done.