Different max loads on the same powder and bullet?

[Elite]

Wondering why nosler as a different max load the hodgdon does for the exact same bullet and powder and primer?

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[wapitibob]

different brass, different rifle

 

[SDHNTR]

Because they tested it in different rifles. Loading manuals are just a very, very rough guide for what you should do in your particular rifle. Every gun’s chamber and barrel will generate different pressure. As will different brass, powder, primers, bullets, etc. even different lot numbers of all those components. Manuals are not gospel, far from it. They are only a good place to start. The max in your particular gun could be significantly higher or lower than the ones they tested when they printed the data in those manuals. What matters is Max in YOUR rifle. The ONLY proper and safe way to find that is to start low and work up slowly in your gun. No other way around it.

 

[bigunit]

Nosler brass would have less case capacity.

 

[A382DWDZQ]

Lots of unknown variables here. we know brass was different and Nosler is seating slightly deeper, but we do not know:

• Barrel make for Hodgdon
• Difference in Nosler data for BT and AB, if any. Could be AB hits max sooner and so published data reflects that.
• We don’t know when the testing was done and under what conditions.
• Don’t know if the lots were different and if they behaved differently.
• Do not know what Nosler is using for max and min pressure. The starting points are pretty close. Nosler is seating a little bit deeper as well.
• Neck tension / crimp
• How far off the lands
• Dog in the reloading room when bullet seated?

 

[Firth]

Everything above is true, I'd just add that even if Hodgdon (or Nosler) repeated their testing with everything as exactly the same as possible, I wouldn't expect them to get the exact same results. That's just how gathering experimental data works - there's always variation. However, I'd bet they wouldn't be 140 fps different as in the case you highlighted, maybe more in the range of 20-30 fps.

 

[Vern400]

This situation is the norm due to variations in test methods and equipment. 61.0 /64.8 is a pretty sizeable difference though. It pretty much means you are on your own! My guess is you may get a few grains over 61. But it depends entirely on your chamber and barrel, and OAL.

My 308 smokes those little 125s with RL15. And they shoot like a laser beam. I use them as varmint bullets at that velocity because they are tremendously destructive. I can't remember exactly but I think I'm running close to 3100 fps with those. RL15 /FED210 tends to drop ES and group size as the powder charge approach is critical. I got in trouble with one batch on a hot day because rl15 is temp sensitive.

You may find the Sweet spot more or less in the middle.

 

[83cj-7]

What will really blow your mind is that W760 and H414 are the same powder, no difference at all. Look at that chart and you can see that the max charge is different. That tells a lot about testing variance.
Some charts show much larger differences between H414 and W760 but Hodgdon usually has it right and shows the exact same data for the two.