Here we go, manufacturers now exaggerate their published data as a sales pitch.
Its the internet expert that reads all this guff then applies his personal interpretation.
Take the Viht thread for example.
"oh barrel burning blah blah blah.." Next publish a letter that the manufacturer supposedly sent... then spin and interpret in own way.
Reality, if one READS the letter the manufacturer does not attempt to quantify the effect (and admits this) of this cataclysmic burning effect. Amazingly enough no one complains of, say, Hodgdon's double base powders...
These threads really show a lack of understanding regarding powders rifles and reloading.
These 'forums' generally are the source of most myths out there. One must remember that the keen amateur does nothing to help safety and knowledge in these matters by repeating these somewhat dodgy interpretations.
How would one explain data from a country that is known to be so litigious can possibly be exaggerated in such a way that allow numbnut reloaders to attempt to chase mystical velocities?
Does one really believe that a powder manufacturer would put their neck on the block like this?
One basically allows the longarm grenade situation, is one sure that powder manufacturers want this situation?
Read manuals, attempt to learn a little about internal ballistics so we can get past all this really bad advise that floats around the 'net.
As to the OP did one read anywhere that the data on the box is the exact performance? Is one's rifle IDENTICAL to the test rifle?
Does one's test conditions, pressure, altitude, temperature match exactly the test conditions that the data was acquired from?
Does one own and use calibrated metrology?
Did one really read ones reloading manuals? Or was it the usual y chromosome skim through the reading bit - jump straight into the data?
If you cannot duplicate EXACTLY ALL THE TEST CONDITIONS, please read that again, EXACTLY ALL THE TEST CONDITIONS, you will never be able to duplicate the results.
Reloading is an absorbing part of shooting and should be treated with respect. Personally I do not give a hoot if one blows ones rifle up in ones face trying to achieve a velocity printed on a box / manual because one did not try and understand the process, consider it a thinning of the gene pool.
I am no expert and do not profess to be, my advise is LEARN and avoid internet keyboard experts who make it up as they go along!
I apologise if this comes over a little strong but promoting useless, in fact dangerous advise must be dealt with at every opportunity.