+ 1 on the 75gn A-Max plus Re15 and/or Varget. This bullet is marginal for the 9" twist and doesn't suit all rifles that nominally have this twist rate. If your Savage likes it, it's the one to use for 600yd - a lot less wind deflection than the 68 and 69gn bullets from Hornady, Sierra, Lapua, and Nosler. It can also be driven very fast safely in most rifles.
Having a quick look at Bryan Litz's experimentally derived real life (G7 based) BCs and running them through the ballistics program, the 75gn A-Max gives an 11" reduction in wind deflection at 600yd in the 'standard' 10mph 90-degree crosswind over the non-VLD 68s 69s 70s that is a calculated 42.5" reduced to 31.4". That's an improvement that's well worth having. This assumes all have 3,000 fps MV which you should find achievable with the 26" barrel Savage.
the 70gn Berger VLD is in between at 36.3", and the 73gn Berger Match BT - a very accommodating and good performing bullet in some rifles - moves 40.2", only marginally better than the 69s. VLDs can be tricky to get to shoot well and many F-Classers avoid them as the need to seat them well into the lands in order to shoot well usually sees the bullet left behind in the barrel and an action full of powder if the order to 'unload' is received during a relay.
Another powder that can be tried is, as suggested by msnations, AA-2520, a ball powder manufactured in the Czech Republic. I found it gave the highest MV I achieved with the 75gn A-Max and good accuracy, but it is a dirty burner and leaves a hard coating on the outside of the case necks that is very difficult to remove if left. (Some people spray WD40 or similar onto the necks straight after shooting to keep the fouling soft and allow it to be wiped off easily.)
Use magnum or BR primers - essential for their harder cups to avoid piercing at top loads, and 'roomy' cases. There are big differences in .223R case capacities. Here in the UK, Winchester and recent manufacture Lapua (marked 'Match' on the carton) are the ones we mostly use. You won't get that many firings out of the Winchesters with top loads but they're cheap - only use them for matches five times. The Lapuas will likely last twice as long in first line use, and a bit longer overall before you get loose primer pockets or neck splits.
Finally, look at the .223 Rem section on the main 6mmBR.com website which has lots of really good information about getting the best out of this cartridge, if you haven't already done so.
The Savage is an excellent rifle (I'm assuming you've bought the 12 LRPV or similar since you've got a 26" barrel) and your daughter will get a lot of pleasure and experience in using the cartridge at this range. The only thing to watch with a Savage is they usually take a couple of hundred rounds down the barrel after initial break-in to smooth out the tool marks and really perform. So don't become downhearted if it only groups 'so-so' to start with.
Good luck and shooting to both of you in 2010!
Laurie,
York, England
