how to reduce velocity extreme spread?

[boomtube]

Good - "Do you understand? You looked at accurate information, you just interpreted it wrong."

Ah. Now I understand. I guess.

You are saying that there are mulitple ways of "interpeteding" a ballistics chart and I thought I was only reading what Hornady says about drop variations at 600 yards due to 100 fps speed differences. Silly ol' me.

Okay, I don't mind saying it, you win!

[AlbertaAl]

I'm a little late chiming in here but I reloaded extensivley for a 300 Win Mag
in a SAKO factory model 75 rifle.

Best load was using:
BERGER 210 seated 4 thou from rifling
LAPUA brass, Federal 210 match Gold Medal primers,
80.0 grains H1000
avg 2853 fps ES 35.67 / SD 13.11
3/8" group @ 100 yds.

Hope this might help your situation in some way !

Regards
AL

[Boss Hoss]

Just to put this to bed hopefully --- I compete at 1K won my share and will tell you that ES is CRITICAL at 1K period end of story. On a competition rifle it will make the difference between winning and not even being in the running or worse yet a DQ. On a long range hunting rifle it makes the variables that you do not have to worry about on a competition rifle become painfully obvious. Vertical dispersion is a killer.

[PDA]

I thought the primer could have a big effect on ES? Am I wrong? It seems so since no one has suggested trying another primer. What about a CCI250 or BR2? Someone more knowledgeable please advise.

[coues7]

Very good thread!

[AtownBcat]

Just got my first chrono...Would someone please take a sec and explain ES and SD? Thanks

[Jamie6.5]

ES = Extreme spread. The maximum velocity variation with a given load.
The highest velocity minus lowest velocity equals ES.

SD= Standard deviation. The average velocity variation of a given load.
Subtract the lowest velocity from all others in a batch of a given load. Add those differences together and divide by the number of shots.