For those of you with chronograph, how close are published factory velocities? I'm mainly concerned with; 25-06 Federal 115 gr. Partitions[3030 fps], 338 WM Federal 180 gr. Accubonds[3120 fps], factory 300 Weatherby 165 grain BT's[3350 fps]. New hunting lease has some big clear-cuts, and 400 yard shots are possibilty. Only have access to 200 yard range, but can use Hornady's ballistic calculator. Thanks for your help.

A calculator is no substitute for shooting at range. Repeat that 500 times and then get a LRF and do the best you can at 200 and limit yourself to 300. Wind, drop wind at different ranges and time all have to be mastered to handle 400. There is not substitute for practice at range.

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For those of you with chronograph, how close are published factory velocities?

You just never know! Some readings are spot on, some are way under, and once in a great while, the factory specs are under actual. This does not happen very often. About the worst I ever heard of were 30/'06 180-grain FL's that were hard-pressed to reach 2400 FPS, about like the 303 British! As mile58 said a calculator is no substitute for actual shooting at long range. You have to allow for mirage and wind at the greater distances.

Probably the only way to know is to shoot your rifle with that ammo over a chrono. The individual rifle makes a big difference in the velocity. You also don't know if the ammo factory got the listed velocity from a universal reciever and a 26 inch barrel. Your sporter with a 22 inch barrel is probably not going to duplicate that velocity. Also published figures have been known to be "optomistic".

Either shoot your rifle/loads over a chronograph, or shoot your rifle/loads at 400yds.

My one example of factory loads over my Chrony is Remington 30-06, 180gr Core-lokt PSP. These went out at 2550fps. The Remmy box is marked 2700fps.

Yeah, there can be as much as 150fps diff. between like rifles so you need to shoot them yourself. If you zero @ 100 then shoot @ 200, you can measure the drop & figure teh vel. out w/ one of the balistic programs & be close.

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I have an old Chrony that I have "proofed" against .22 match ammo which is surprisingly close to its stated velocity and against other, high-dollar chronies and it has been consistant enough to suit me. As a rule, it gives me lower velocities than those of the manufacturers and the load books. I use my velocities for any calulations I make.
I agree with the others, you should not attempt a shot on an animal using scope adjustments you have made from a load book or computer program without testing them first.

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Originally posted by SIR MAUSER:
For those of you with chronograph, how close are published factory velocities? I'm mainly concerned with; 25-06 Federal 115 gr. Partitions[3030 fps], 338 WM Federal 180 gr. Accubonds[3120 fps], factory 300 Weatherby 165 grain BT's[3350 fps]. New hunting lease has some big clear-cuts, and 400 yard shots are possibilty. Only have access to 200 yard range, but can use Hornady's ballistic calculator. Thanks for your help.

I think you may be splitting hairs. The difference in 100 or even 150 fps muzzle velocity will not change the downrange impact point appreciably. Comparing the 100 yard and 200 yard impact points of your factory loads will tell you if there is something significantly amiss.

Assuming the 100 and 200 yard impacts are consistent with calculations for those ranges, velocity differences won't cause you to miss a deer at 400 yards (although many other factors might). For example, the .25-06 partition at 3030 fps with a 200 yard zero will be 18.9 inches below line of sight at 400 yards; the same bullet at 2930 fps will be 20.4 inches low -- only a 1.5" difference.

If you are not experienced at long range shooting there are plenty of things that can trip you up: Wind drift, mirage, inaccuracy in ranging the target, and the amplification of your gun's inaccuracies since a 2" group at 100 yards is an 8" group at 400 yards. You see, there is so much more that can go wrong than an error in estimating muzzle velocity that muzzle velocity becomes the least of your worries.

I also can not answer your question directly. However, I can tell you that I have never seen a factory load that lived up to it's claims.

Id head out to the new lease and shoot some paper at the distances you might want to shoot at game; and then you will know your and your rifles capabilities. God Bless, Louis

Louis has the right idea .. Actually shoot at the ranges you will hunt at ..... However a larger issue than short range drop ie 400 yrds is the time of flight when dealing with the wind ...........
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. I recommend you get a chronograph , and shoot at the distances you will hunt at ...........

Its more like guide lines.