Most accurate load data sources

I cross reference load data from Lyman ,Hornady, Sierra ,Hodgdon and usually the powder manufacture. Then I usually pick out a load they all agree on or at least come close to. If I can't find something satisfactory that way I'll go to a single source. Usually Hornady's manual. But then again I use their recommended component's most of the time. Make sure it's your loads that are off and not yourself. I've gone to the range and have had an off day then the next day go back and everything is right on with the same loads as the day before. Sorry but can't make recommendation on the most accurate and correct source. I'm not sure one is better than the other all the time and a lot depends on your gun and other variables unique to you and your equipment . If you are a reloader you have the means to experiment. That's why I reload anyway

I've found Lyman to be most consistent. I've never had a load from my Lyman book that's resulted in unsafe pressure, and I've never had a load from Lyman that was anemic. It's usually just right and the max load in the book is right where I start seeing recognizably high pressure. So the data is hot, but I've always found it to be safe. The velocities stated are usually accurate too.

Keep in mind that the starting loads stated in the manuals are not necessarily where you need to start, that often just indicates the minimum that can be used and still result in consistent combustion. You're generally safe starting 10% under max. So if the data says 30 grains start and 50 grains max I would start at 45 if your not interested in a lower power loading.

I usually find a happy load between 5-10% under max but I often work up to the the max just to document the results.

I'm hesistant to declare one source "most accurate." I consult a number of sources (four manuals plus Hodgdon reloading site plus QuickLoad plus others at times). I'm not usually after a "hot" load but rather accuracy. So I tend to start at the low end.

Loads for harder, high friction bullets (solid copper and steel core) tend to be lower than for lower friction bullets (thin jackets, soft lead core) with some hunting bullets in between (thicker jackets, harder lead core). Brass volume can also affect it. QuickLoad allows you to try brass from different manufacturers as well as different bullets of the same weight. You can also measure the internal volume of YOUR brass and tweak the setting in QuickLoad to match.

The moisture absorbed by the powder can also have an impact. A freshly opened powder container will be "hotter" at the same load weight than one that has been opened and exposed to humidity for a few days. I've been controlling the humidity in my reloading area for the past few years and leaving new containers open for a few days to reach an equilibrium before loading.

My opinion? There is no one most accurate source of load data. This is especially true when you are loading a caliber like .308 Winchester for several different rifles. I load for an AR10 and M1A match rifle as well as a Remington heavy barrel bolt gun. While I like the Speer and Sierra match bullets in several weights my powders do vary. The one powder I like across the board is likely AA2495. For my gas guns, the AR10 and M1A my favorite bullet is the Sierra #2200 168 grain match king. The slowest powder I like is IMR 4064 in either gas gun but many use and swear by Varget, I never got good results with Varget in my gas guns.

I really do not see any one set of manufacturer's load data, bullet or powder as any better or worse than the next. I see it as a matter of trying and finding what works best in your specific rifle.

<EDIT> My apologies as I typed Unique rather than Varget. I changed the post to reflect Varget and thank you Jim and Jack for questioning that. Damn, head up my butt this morning, </EDIT>

Ron

Unique for .308? Really? I know it is in Lyman CAST bullet data but it would sure not occur to me to use it for anything more.

I'd never use unique in a rifle. New one on me. Live and learn. Wonder where you can get load data from.

I corrected my previous post #5 to reflect Varget and have no clue why I was thinking Varget and typed Unique other than to blame it on getting old. The good news being I have not confused the two powders on the bench. Thanks Jim & Jack for questioning that.

Ron

mercervillerental said:

a really rough range trip...

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...boy, I've had some of those! Things have a way of turning around quickly though.

For a newer reloader, when in doubt use the lowest listed load data. Reloading manuals are not exacting formula, they are published results of what a specific lab tech found when the listed components are used and tested on his equipment ( thus being "no where near each other"). Manufacturing lots will differ and equipment will differ (even slightly). For a new to me cartridge, I'll start with the bullet manufacturer's data, manual, and if I'm using cast bullets, I'll usually go with Lyman data.

Reloading isn't an exact science as there are too many variables, the most being the gun used...

FWIW, I've used Unique and WC820 in handloads for my .223, jacketed and cast...

mdi said:

Reloading isn't an exact science as there are too many variables, the most being the gun used...

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+1

Several times I have picked up cartridge cases that had the same headstamp but, as they were fired from different guns, had slightly different shapes, usually around the shoulder and neck.

I never trust any one source of data when developing a new load. I generally will reference at least three sources of published recipes before deciding on where to start/stop, generally throwing out any extreme high/low powder charges until I experiment with those loads that tend to agree. I've found many times Powder Company load recipes are hotter than Bullet Manufacturer recipes. I've often wondered if one was more interested in posting top velocities where the other was more concerned with top accuracy. While most forms of reference will give you their "most accurate load" I've found what works best for them doesn't always work the best for me.

The one that works out for you. You will probably have a different one for every firearm.

mercervillerental wrote:
In general are certain sources of data considered to be more conservative or aggressive?

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No.

The published manuals and the powder manufacturer data are compiled using different test platforms with powders and components that the customer is likely to be using. A safe starting load that delivers useful performance is published along with a maximum load that is generally determined by when the maximum chamber pressure is nearly reached.

You didn't mention the weight of bullet you are loading nor did you mention which edition of the various manual(s)/source(s) you were consulting. But per Hornady #8 (and #9), with 165-168 grain bullets, the range with Varget is 32.6 starting load up to 44.0 grains. Lyman #49 with 168 grain bullets has a range of 41.0 to 45.7. And the Hodgdon website gives 42.0 to 46.0 for both 165 and 168 grain bullets.

Apart from the very light starting load Hornady uses, the maximums are within 2 grains of one another. That's very consistent given the difference in the testing equipment that was used, the length of the barrels and the differences in COAL.

If you're chasing velocity as a principal consideration, then exclude the light load in Hornady and take a concensus among the remaining sources. Looking at the above, we've got Lyman #49 at 41.0 and Hodgdon at 42.0. Pick a starting load of, say, 41.5 and given that's 4.5 grains off of the maximum load, ladder up in 0.5 grain increments, stopping as soon as you see pressure signs. Once you see pressure signs, go to the next lightest load that didn't produce pressure signs and then work around that charge in 0.1 or 0.2 grain increments until you find the most accurate load. That will get the most accurate load from your gun in the velocity range you're seeking.

"...lowest starting charge is..." For what bullet weight? There's no Varget load that is 32.6. 32.6 is way below minimum for any bullet weight.
"...the most accurate sources..." That'd be all of 'em. Like hdwhit says, no 2 manuals will ever be exact. However, it's best to use the powder maker's or Lyman data. That does not mean the powder or bullet maker's data is bad. It's just not as versatile. Biggest difference will be velocities.
Lee tests nothing themselves. They use Hodgdon data or the powder maker's data.
You'll see posts on some forums that claim manuals are written by lawyers. That's nonsense.

Sunray said:

You'll see posts on some forums that claim manuals are written by lawyers. That's nonsense.

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Yep. I've been practicing law for a while now, and am familiar with a lot of different law firms. I have yet to encounter one that has a pressure testing facility!

mercervillerental said:

After a really rough range trip I'm questioning my load data. I'm wondering what the collective opinion is on the most accurate sources. I have Horndy, Sierra, Lyman and the powder manufacturers. In some cases the load ranges are no where near each other.

For example, I'm loading for an AR10 with Varget at the moment. Between those sources there are 5 vastly different load ranges, including Hornadys SR section (which I'm not sure I should be looking at or not). The lowest starting charge is 32.6 and the highest is 46. Is it even possible that all those ranges are perfectly acceptable? If so are there any recommendations on how to even develop a starting load?

In general are certain sources of data considered to be more conservative or aggressive?

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use the manual that uses your bullet. there are so many different bullet shapes and sizes that load data for your bullet is going to be the most accurate.

luck,

murf

As others posted, there are testing variables such as barrel fixture/length/harmonics, bullet, case, primer, etc. which will produce differing test results.

For my load development, especially for rifle, I try to match the components used in published load data.

If I cannot match the components used in published load data, I will use more conservative start charges and conduct my powder work up while looking for accuracy nodes. Once accuracy nodes are identified to 10th of grain, I will incrementally decrease the OAL/COL to see if accuracy improves.

All of my best loads were "borrowed" from others. If you spend enough time on various internet boards people will usually share loads that have worked well for them. I know of some forums where there are open threads going back as much as 10 years where people post load data that has worked well for them for specific cartridges.

If you read through them, or ask for load ideas here and on other forums you start to see trends. If you find a lot of people getting good results with certain combo's then chances are good it will work well for you. It certainly eliminates an awful lot of trial and error.

I wouldn't blindly use another persons data. But if I can confirm that load in a dependable source I'd start low and work toward it. I may not find the best results at exactly the same charge weight, but usually find it somewhere close.

I've had a couple loads from Speer and Accurate Powders that made my eyes come out of my head when I saw how high there max loads were. I tried to work up to a couple of them from Speer and got to pressure levels that made me stop before getting anywhere close to max. Others were to insane looking to even try. Accurate's data is all over the place and they sometimes list powder and caliber combinations that have no business being together. During the powder shortage I tried AA7 in 357 mag. Half way between starting and max the pressure was so high I could not push the brass out by hand, I had to lean against a fence post to get the brass out. Other loads from accurate, particularly rifle loads, are so anemic at max loads it doesn't even burn all the powder. I've always found hodgdon's data to be quite conservative in many calibers, but consistently pretty accurate. I don't use Aliants data much since there online data is kind of rinky dink and often incomplete.

Lyman and Hornady are my favorites and I go off them almost exclusively. What they say is a max load really is a max but it's always been safe and sane in my experience. Also they only list powders that actually have a good chance of working well in the caliber, and they usually use realistic test barrel lengths for velocity testing.

I've had pretty good success using the Nosler manuals, but most of the bullets I shoot are Nosler. They list "most accurate load" with each powder and I've found they are often in the ballpark for my rifles.

Somewhat like JMR40, above I've found the internet to be my most valuable source for load information. I got my load for a 30-06 right off this forum. I was moaning about the difficulties I was having and someone posted a load that he said worked for about everyone. It sure worked for me and I've never looked back.