Different Load Data from Different Sources

[lwestatbus]

I am trying a new powder (Winchester 296 Ball Powder) and encountered different starting and max loads from different sources. I want to load .44 Mag 240gr jacketed bullets and the sources are the Lyman 51st Edition Reloading Handbook and the Hodgdon web site. The Hodgdon site lists starting and max loads of 0.5gr higher than the Lyman Handbook. Both sites SEEM to use similar test beds, though the Lyman Handbook lists multiple barrels for all of its .44 Mag loads without specifying which was used for a specific load.

I realize that the fundamental issue is working up loads to safe loads with the characteristics I want them to have. I can easily pick a starting load that is in the lower end of each source's suggestions. However I often have a 1- to 3-week time delay between testing loads where I can set up my chronograph. I'd like to get closer to the final load on the first try so I need at most one tweak.

What I usually do with a new load is load three versions at once so I can fire all three in one range session:

1. Suggested starting charge
2. Half-way between starting and max charge
3. 80% of the difference between starting and max charge. [Edited to add underlined portion]

I fire them in order and capture velocity and sense feel and look for signs of excess pressure.

Do any of you even check multiple sources for your starting loads or do you just use one source and work up from there?

[Jim Watson]

The Hodgdon site lists starting and max loads of 0.5gr higher than the Lyman Handbook. Both sites SEEM to use similar test beds,

Bullets? Different brands of the same weight bullet will often get different powder charges. It must be some combination of seating depth, bearing surface, and hardness. This shows in my Lyman 49, there are two 240 gr jacketed and two 240-245 gr cast, none have exactly the same maximum load.

At the risk of contributing to the delinquency of a reloader, I can say that back when I was shooting IHMSA, the most common .44 load was the Hodgdon 296 maximum with a 240 Hornady.
Note that 296 has, or had, a narrow range of application, Hodgdon only gives a one grain reduction from maximum to starting.

[tangolima]

I check different sources. Load data are often different. How to reconcile is each loader's "secret sauce". Starting from the conservative side is an obvious and sensible choice.

Difference between min and max is often 10%. For instance, min 9gr, max 10gr. So 80% max would be below min. Did you mean 98% max? In example above, 9.8gr.

For a new load, I usually include a "ladder" from min to max with a couple of rounds of each step. It is for checking pressure signs only. Very important to have firm criteria to abort. Pretty silly to insist firing them all.

We all want to have more done during each trip to range. But do resist the urge to cut corners. At least don't do it before we know where to cut.

-TL

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[Metal god]

I consider myself an experienced reloader and the other day I went to go load up some 175 gr Sierra match Kings with IMR 4064 . I checked the Sierra book and their Max was 42 point something . In the Hogden website with the same bullet has a max of 45 point something compressed . A 2.5gr+ difference surprised me because I can usually work out the reasoning, but I can’t on this one. The difference is too much imo to be a case difference or different primer or whatever 2 1/2 grains is a lot in my opinion . 1gr to 1.5 seems pretty normal in a 40gr cartridge but 2.5 ….

I ended up splitting the difference and went up to 44 grains , I just couldn’t bring myself to loading 45 grain loads, thinking I would ultimately end up having to pull the bullets

[stagpanther]

I went through my 44 mag phase and shot a lot of it through lever carbines and SA revolver; I'd agree that 240 gr bullets driven by 296/H110 was pretty much the sweet spot given the typical twist of my guns. I found that the 44 mag case is big enough that a small capacity charge can sometimes result in a hangfire with the right [wrong] combination of bullet, powder and primer.

[ligonierbill]

I almost always check multiple sources plus QuickLOAD. Yes, they do vary, which of course is why we test ourselves.

And data may reflect a different "philosophy" between testers. Metal God's example is a good one.

Checking those data against QL, Sierra ran a fairly full case and stopped 4064 testing at a lower (estimated) pressure, right at the bottom of QL's caution zone. Pretty conservative. Why? They don't say. Maybe accuracy fell off.

Hodgdon actually published their measured pressure 59,500 psi. That's 4% below SAAMI max. Personally, I'd sneak up on that load, but it's certainly in spec.

Measured velocities reflect the pressure difference, so it's less different measurements than choices made by testers.

[Rimfire5]

The one thing to be careful of is the rig they are testing with. Barrel length differences will make a difference in your results. The good manuals I have used list the type of rifle and barrel length used to generate their test results.

The other thing that I have never seen in a manual was the temperature that they experienced during their test.
I don't think that W-296 is a temperature insensitive powder so it might change up to 1.24 FPS per 1 degree F. difference.
So if the powder data is specified for 59 deg F. like most US powders, shooting at 30 or 40 degrees or 80 or 90 degrees would change the velocity results and the chamber pressure considerably.

Years ago, I migrated to using QuickLOAD, primarily because I could insert seating depth, trim length, and temperature along with barrel length when I was trying to figure out a load. And it also predicts muzzle velocity, chamber pressure, case capacity used, and bullet exit time. I have validated the predicted velocities with actual measurements and the numbers are well within a reasonable range and the measured SD, assuming I have included the specific data for my rifle and my loads.

Tuning for exit time can help reduce harmonics at the muzzle if you know the steel in your barrel and its exact length and that improves accuracy in my target rifles.
Spoiler alert: Most of my most accurate rifle barrels are not the exact length that is listed in their specs. They are not far off, but enough to change the predicted exit time.

QuickLOAD has taught me a lot about what is missing in published load tables.

[tangolima]

Originally Posted by Metal god

I consider myself an experienced reloader and the other day I went to go load up some 175 gr Sierra match Kings with IMR 4064 . I checked the Sierra book and their Max was 42 point something . In the Hogden website with the same bullet has a max of 45 point something compressed . A 2.5gr+ difference surprised me because I can usually work out the reasoning, but I can’t on this one. The difference is too much imo to be a case difference or different primer or whatever 2 1/2 grains is a lot in my opinion . 1gr to 1.5 seems pretty normal in a 40gr cartridge but 2.5 ….



I ended up splitting the difference and went up to 44 grains , I just couldn’t bring myself to loading 45 grain loads, thinking I would ultimately end up having to pull the bullets

42.5 to 45gr is 6% difference, which is quite a bit, considering min and max in manual is usually 10% apart. In such case I would consult more data sources. If I decide to shoot it, I would prepare loads to include between 42.5 and 45. If I feel comfortable with 42.5gr, then I would sneak up above it in 1% steps.

For temperature, my rule of thumb is 0.05% per degree F change in mv. For instance, 3000fps at 70F. At 100F, it will be 1.5% higher at 3045fps. I actually adjust my load up or down according to the expected temperature at the range. The idea is to maintain the same MV.

Another rule I go by. For every 1% MV change, chamber pressure move 3%.

-TL

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[44 AMP]

Their test gun and components and your test gun and components are NOT the same. Similar is possible, but identical is not.

Similar means yours and theirs is going to be on the same bell curve of performance, but WHERE on that curve yours is, and theirs is are not likely to be in exactly the same place.

What is usual, and what is possible are different things.

Accept that, and move on. Reloading data is a guideline, and while its pretty accurate stating what they did, and what results they got, your gun and ammo combination is going to be at least slightly different, and could be quite a bit different in all aspects.

[Rimfire5]

TL,

Your rule of thumb is right on at 0.05% for most old powders at 2500 fps.
For VV powders, it is more like 0.032%
For temperature insensitive powders, the factor is around 0.0025%.
The percent change per degree F. is just about linear, but as the MV increases the factor drops slightly because the divisor is increasing.

For example:
For a MV of 3000 fps, the factor is 0.041% for most temperature sensitive powders.
For VV powders at the same MV, it is closer to 0.027%.
For temperature insensitive powders, the factor is 0.0021%. The impact of that factor for TI powders is not worth worrying about unless you load for the equator in summer and then shoot in the artic in winter.

That's why my 'go to' powders are temperature insensitive when I can find them.
My favorites TI powders are Varget, H4831, H4831 SC, H1000, and H4350, depending upon the caliber.

QuickLOAD doesn't even recommend adjusting for temperature for Temperature Insensitive powders. But they do recommend adjusting for temperature when using all other powders.

[tangolima]

Originally Posted by Rimfire5

TL,



Your rule of thumb is right on at 0.05% for most old powders at 2500 fps.

For VV powders, it is more like 0.032%

For temperature insensitive powders, the factor is around 0.0025%.

The percent change per degree F. is just about linear, but as the MV increases the factor drops slightly because the divisor is increasing.



For example:

For a MV of 3000 fps, the factor is 0.041% for most temperature sensitive powders.

For VV powders at the same MV, it is closer to 0.027%.

For temperature insensitive powders, the factor is 0.0021%. The impact of that factor for TI powders is not worth worrying about unless you load for the equator in summer and then shoot in the artic in winter.



That's why my 'go to' powders are temperature insensitive when I can find them.

My favorites TI powders are Varget, H4831, H4831 SC, H1000, and H4350, depending upon the caliber.



QuickLOAD doesn't even recommend adjusting for temperature for Temperature Insensitive powders. But they do recommend adjusting for temperature when using all other powders.

I have limited funds, so I have to use whatever powders available. Temperature is a bit imprecise. It is the temperature in powder column that counts, which is not quite the same as ambient temperature. For bolt gun, it isn't bad. I chamber when I am ready to fire. For gas gun, it always chambers immediately unless I do single loading. If I linger longer before firing, the temperature becomes a bit of unknown.

Where we are, temperature year round is from 30 to 110F, or 80F variation. That is up to +/- 2% in mv, not really nothing for me.

-TL

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[Unclenick]

Back when 296 came out, Winchester had a zero load range for it. They published a fixed value for each application. It was 24 grains for 240-grain bullets in the 44 Mag. I used it back then and still do. This was for a jacketed soft point. A hollow point would be slightly longer, so there's no harm in starting with 23 grains instead.

Note that SAAMI has both solid and vented test barrels for 44 Magnum. Most commercial ammo has velocities on the listed on the box for the 4" vented barrel that mimics a revolver, with the vent acting as a barrel/cylinder gap. Hodgdon uses the longer solid barrel that mimics a single-shot silhouette pistol.


Metal god,

Especially if you are using military brass, try using the load Federal developed for Mk 316 mod 0, 7.62 NATO sniper ammo using the 175 grain SMK. 2.7 grams (41.67 grains) of In MR 4064.

[Metal god]

UN , that’s basically Hodgdon’s start load . I don’t have the test loads I loaded up in front of me but think I started at 42gr . If I don’t find anything good tomorrow when testing , I’ll try that load out next .

[Unclenick]

Hodgdon uses Winchester brass, and the data isn't new. Twenty years ago (not far from when a lot of that Hodgdon data was developed), I bought 500 unprimed Winchester .308 cases, and they averaged about 156 grains and had about 59 grains of case water overflow capacity. By comparison, military brass was weighing almost 180 grains on average and had about 56.5 grains of water overflow capacity. These days, Winchester has gotten a little heavier, at just over 160 grains, and the military is unchanged. In any event, what constitutes a starting load for old Winchester is going to be about 2 grains higher than what achieves the same peak pressure in a military case, using the old numbers. I've forgotten what the specially made Federal brass for the sniper ammo has by way of case water overflow capacity, but it is lower than old Winchester, and at around 41.7 grains, it is at about 100% loading density under the 175-grain SMK.

[stagpanther]

already said it--delete.

[Nathan]

People may not like my viewpoint on this, but here it goes. Frankly, I find that published loads are more likely to cause wrist soreness than blowing up your revolver, if it is a solid gun built for SAAMI spec loads.

So, I tend to gather load data from multiple sources, add in some info from GRT or Quickload. Then load a ladder. The purpose of the ladder is to look for pressure signs, excessive recoil signs or velocity too high or too low compared to the data. From there, any good looking load with reasonable recoil and velocity and no pressure signs, I will load some kind of OCW using the ladder result as max. I also use the ladder target(1 round per bullseye) to show me what charges are shooting in the same zip code, for reduced powder variation effects.

Then from this 1 - 3 set of 6 or 12rd(revolver) OCW groups, I try to pick a best load. In revolver, I don't mess with seating depth.

End result is my 629 5" with a RDS shoots a 10" plate at 100 yards pretty easily.

My point is load recipes are not like muffin recipes. You are likely going to be changing gun, barrel length, bullet shape, etc. . .so you have to redevelop the recipe. Ladder and 10+rd OCW groups are the way to get this done.

If a person is uncomfortable with what I have outlined above, calling the powder and bullet maker for advice may help narrow things down a bit so your judgement is not required as much.

My main advice is if you are getting more velocity, you are getting more pressure. period. There are few magic pills related to the gun increasing or decreasing velocity.

If you don't have a chronograph, get one. They say you can reload without one, but it helps and it is easier than figuring out how to grow fingers! My dad never had one. He leans very conservative when he reloads.

[Metal god]

I looked back at my case volume test from years ago. I’ll only post the volume numbers but FWIW only the Lapua brass weighed below 180gr averaging 179.4gr

LC-10 = 54.86gr avg / ES = .6gr

LC-14 = 55.12gr avg / ES = 1.2gr

LC=09 = 54.9gr avg / ES = na

LC-12-LR = 54.97gr avg / ES = .8gr

Lapua = 55.6gr avg / ES = na

I know I did others like Federal , Winchester and Remington . But can’t find my notes on those right now . I know What I think they were but not confident enough in the memory to post it .

As I was writing this I came across more notes

Federal Gold medal match brass was 55.49gr avg / ES .8gr

I also came across notes that clearly show each rifle will have its own unique fire formed cases, resulting in very different numbers .

Example : my Ruger precision rifle in 308 using LC-10 cases had an avg case volume of 55.3gr which was different then My Savage Fcpk which was 54.86gr I don’t have the Ruger PR ES

Same with the LC-12-LR in the Ruger - 55.6gr vs 54.97gr

I don’t think I’m gonna find the others. I just don’t know where to look , I may come across them someday, but that day is not today.

[lwestatbus]

Sorry for the radio silence here for a few days. Was babysitting a 7-year-old grandson away from home.

Thanks much for all of the insights. As is often the case I learn more about deep principles on this forum than the answers to the questions I post.

Bottom line is that, yes, different sources do have different load data for the same cartridge / propellant / bullet weight & type combinations.

One conclusion I reached is that, in most cases, I don't necessarily need to push loads to the max they could reach. I am reloading revolver cartridges in .38 Spl, .357 Mag, .44 Spl, and .44 Mag. All of my shooting is under 100' with most under 50' (though Nathan's 100 yd shots are something to aspire to). I am shooting in late model S&W revolvers.

My question was mostly out of curiosity and I'm pretty satisfied with my methodology of creeping up on the upper end of the range but not needing to reach it as long as I am getting servicable performance.

BTW for those who use a minimalist approach to laddering, I still shoot 5 rounds at each load because either I or my chronograph don't always get it right and I need the five rounds to be sure I get enough observations to judge the performance.

[RC20]

I always try to get multiple sources. 6.5 Lapua has limited data but a general look at 6.5 CM and being conservative works. The Lapua barrel is gotten eratic so put on my CM barrel.

Pistols as well, I have new references on the shelf and old ones and cross check there was well, I am using some older powders so the older references are a good starting point.