55 gr Vmax And H335

[TFL]

Did not want to Hi Jack this Thread 55gn Vmax powder charge?
So I will post it here
Not to confuse the issue
55 gr V-max SD .157 BC 0.255.
Speer, 55gr spitzer-sp SD .157 BC 0.255
1998 Speer manual 13 H335 mag primer 24.0 2805 vol 26.0 3092 vol 22" bbl 1-12 twist
1988 Speer manual 11 H335 Mag primer 25.5 gr 2984 vol 27.0gr 3193 vil 18" bbl 1-10 twist
2010 Hornady 8th edition H335 20.8gr 2800 vol to a max of 23.4 at 3100 vol. 26" bbl 1-10 twist.

Why the difference in load data between the books if it was safe in 1988 why is it not safe in 2012?

 

[cfullgraf]

There are many reasons load data changes over time.

Some of them are...

Different powder lots.
Powder formulation changes a bit.
Different manufacturer of the powder.
Different firearms or test rigs used.
Different testers.
Different test methods (CUP vs PSI for instance)
Different atmospheric conditions.
Different projectiles.
Different components
Change in industry standards
Different lawyers
Different phases of the moon

And many others that I cannot think of.

Clear as mud?

 

[hentown]

You left one out....attorneys.

 

[jim243]

Apples to Oranges, Apples to Oranges.

Jim

 

[TFL]

Apples to Oranges, Apples to Oranges.

Jim

same BC And SD everything same except twist and bbl lenth.

 

[Clark]

I have worked up loads with the .223, H335, and 55 gr Vmax.

Here is my schpeal:
Remington registered the 223 at SAAMI for 55,000 psi. [36% safety margin]
Winchester registered the 270 at SAAMI for 65,000 psi. [3% safety margin]

When I say safety, that is not personal safety, that is margin to keep from having loose primer pockets and thus short brass life.

From 2007
http://www.thehighroad.org/showthread.php?t=303359