Maybe there isn't a need to cross reference but it surely would have helped prevent a blood pressure spike that I experienced late this afternoon.
I am new to .223 reloading... and finally decided to process a bunch of brass and get going on loading since my sons are shooting ARs.
I broke out the Speer Manual, #12, and noted the data for 55 gr FMJ-BT using W748. Speer recommends that I start at 26.0gr and max at 28.0 (compressed.)
So I loaded 100 rounds at 26.0 grains and asked my boys to bring the brass back to me. They were there, hands on for a bunch of it, watching the powder drop and every 6th a check on the scale.
(Q: Why every 6th? A: Once per row of the loading block. Just easy to keep track of.)
Each of the shooters shone a flashlight above the loading tray and into the case necks to see what 26.0 gr of 748 looks like in there, and that all were about the same depth.
All good, I thought.
The boys took off for the range and I sat down to clean and calibrate 4 beam scales, disassemble 2 powder drops for a deep cleaning, and put things in order after having 5 guys monkeying around in my loading area. As I put the Speer #12 back on the shelf, on a lark I grabbed the Hornady Handbook of Cartridge Reloading, 6th Edition. I turned to page 183, enjoying the crisp pages and data flowing under my fingertips. 2 more pages slide past as I get to the 55gr data, and there to my great wonder I saw that I had sent my boys out with cartridges loaded to .4 gr short of Hornady's Max.
Hornady starts at 22.7 and maxes at 26.4. Both used a test bbl of 1-12", but Speer's was 22" long and Hornady's 26". Speer's COL 2.215, Hornady's 2.200".

When I was teaching my boys to reload I rammed it home about starting low and working up pet loads for each rifle... And now I have to tell them that I sent them out earlier today at almost max from one source!

I suspect that all will turn out just fine.

But yeah, it's frustrating when you get all super-careful about your loading, and then you find such a wide variation in data. A reloader just don't know what to do.

Hornady rifle loads are very conservative. You have to take that into account.

And these loads were for bolt action rifles? I've read different load data by the same mfg for bolt and semiauto.

Good point sir. I am a bolt action guy. I've never even shot my own ARs.
Speer's test rifle is the Ruger 77 MkII. Hornady's is the Remington 700. Bbl specs in 1st post.

Duke, I'd have gone with the more conservative if I'd been aware of how big the discrepancy could be. But one manufacturer's minimum is about the same as another manufacturer's maximum? *blood pressure spike* I'll be checking all my books and going online the next time I start a new-to-me cartridge.

That is always a wise move. Also make sure to check with the powder manufacturer's load guide as well as the bullet manufacturer's.

I've been experiencing similar frustration trying to start loading for my Mosin Nagant. The low end load data I've found for the powder I have varies almost 10 grains depending on which source you refer to!

I'll be starting with the lower low end data I found in my Lee manual.

So outrageously conservative. The Hornady manual is a paperweight. Use the powder manufacturer or Lyman manuals.

For shame! For shame! Mr Tools of Freedom!

They just don't appeal to me much.
Even when I was loading for the ARs I was thinking how much nicer it would be to shoot that shiny ammo in a bolt gun.

On a related note, I'm in the market for bolt guns in 5.56 and 7.62 NATO.

This matches the Hodgdon site, FWIW. While not good or ideal to start near the max, as others have mentioned most max weights have a layer or two of safety built in (not advising to ignore, just stating an observation)

I would say with the 55 gr bullet, firearms in good working order, you will be fine at 26 gr.

With hot pistol loads, many folks I know in certain firearms test to the max load and then creep beyond. With my 10mm AR, the chamber is very stout, a couple loads I have gone beyond max book and zero signs of high pressure. Again, just my own personal business.

I have only ONE manual, the Lee 2nd Edition. I use it for a basic reference as it has quite a comprehensive load database. For the actual loading I use the manufacturer's website as that data is the most current. Printed manuals take a couple years from start to publication and often there are small changes that don't make it into the final copy.

The basic rule of reloading is to establish a starting point (low) and work up your loads to suit your own rifle. Sometimes it's higher than published data and sometimes accuracy comes at a lower than published load.

We've moved into the 21st century and it's time to put the books where they belong. On the shelf of a museum showing 20th century technology.

There's a margin of safety built into all of the loads. If you exceed it slightly, accelerated wear on your bolt and stretched brass are more likely than catastrophic failure.

None of this is rocket science as you're using their data in a different tube with only the crudest methods for monitoring pressure. That's why everything is kept well below dangerous levels and most accidents happen with double charges, wrong type of powder, or other MAJOR pressure spike.

I usually do a sanity check (if I have several manuals with data) and then rely on chronograph and pressure signs to make sure things aren't wildly wrong.

The other thing to note is that load data is typically given for .223 Rem pressures. Most AR15s are chambered have a more generous chamber and throat (for 5.56 ammo), so loading a bit hot won't be an issue.

Bolt guns are inherently strong, so while they may have tighter chambers, they can often handle fairly high pressure safely.

It's always best to work up loads to your rifle, but what I'm getting at here, is that I wouldn't be concerned with going up to, or even slightly over book listed maximum loads. Don't go too crazy, be reasonable

I have 3 books, hornady, lee, and lyman. I definitely use the websites too, western powder, hogdgon, vihtavouri, and Nosler. Books still have a place, but the web sites is where the most current info is usually.