Having recently purchased my 264 winnie, I was eager to reload, consulted several bibles, and came up with a load!
Hodgdon figures stated H1000 start @ 66.8gn- 71gn max giving 3187fps for max load for 129gn hornady sst.
As this was a rush job decided on 68gn well under max or so I thought!
I had difficult extraction which I put down to just neck sizing,I chronoed the load which came out at 3347fps, which is well over the top.
God only knows what the result would of been if I had gone for max load of 71gns..
My other question is : what is acceptable variation in fps when reloading, my recent loads came out at 2980fps-3040fps giving a variation of 60fps, would this be acceptable and can it be improved upon?

regards
griff

The books data is accurate for the components and rifle used to develope it. The problem is your rifle and components are likely quite different. This is the reason for starting loads, and why one should "work up". The max in the book may or may not be the max in your rifle.

How many rds did you fire to get your 60fps ES? If that`s for 3 rds I`d want better, 10rds and it is looking fairly good. The lower the spread the better but it has to be with a large enough sample to have meaning.

I for one would love to know what the 71 grain charge would have yielded as to velocity. But also shutter to think when concerned about pressure. On the variation in the larger cartridges a primer change may reduce the 60 fps variation, but so could a change in neck tension, a minor adjustment in seating depth, or sorting cases by weight or flash hole size. Such is the natue of reloading and the accuracy quest. I also had a similar reaction to H1000 and changed powders. This may or may not have been the best thing for me to do, but velocities were low, and pressure seemed high at the time. Good shooting and careful work up.