Anomalous initial velocities

[David P. Herne]

Gents,
Today I was at the range testing a new load that yielded results which left me quite perplexed about the tendencies of certain loads despite current published data. Specifically, I've found a load using the Lapua 167-gr Scenar that, for whatever reason, wants to come out of the barrel at much faster than the mean initial velocity indicated in the reloading manual I'm using. Meanwhile, another projectile, the Lapau 185-grain Scenar, refuses to go any faster than the published data suggests. Mind you, this is happening despite strict adherence to the published data and withstanding control of all other variables. Have any of you ever seen such a phenomenon?

Regards,
Dave

 

[Darryl Cassel]

Houston

I have found "many" differences and false advertising in published loading manuals from the manufacturers, over the years.
A slight difference of barrel length, amount of grooves and land depths can change the published velocity in most any cartridges..

Best to start low and work up your own loads
from actual fire tests and with "your" rifle.

I found one load in a manual that I could go 12 grs more powder then was listed, before encouintering ANY pressure signs.
This was a rare find and don't reccomend adding 12 grs to the max in a loading manual but, the fact remains, it was there.

Bullet manufacturers have a tendency to want to sell their new line of bullets by adding some numbers to make it attractive.

Later
DC

 

[MAX]

I'll second that. Seldom if ever do I find correlation between load data and velocities that MY guns shoots. Sometimes better, sometimes not. Sometimes the difference is substantial.