The longest distance I can shoot at in the shooting range is 100 meters. Can I trust the trajectories that reloading manuals predict at longer distances based on the point of impact at 100 meters and measured muzzle velocity?
Thanks.
Montero

If you can only shoot at 100 yards, and know the velocity by measurement you should be able to predict impacts out to 300 yards on deer sized game (six inch kill zone.)

I successfully predicted impact at 600 yards from muzzle velocity, ballistic coefficient and 100 yard zero, but that was with paper as a target.

Basically if you can't practice at 300 you shouldn't shoot game at 300, IMHO.

Don

Actually, the mathematical calculations are probably more accurate than shooting at different ranges because they take all the variables out of the equation ie. shooter error, headwind, tailwind,altitude,scope height, etc. However, the tables in most reloading manuals are based on a given set of parameters which most likely won't match yours exactly. A better way to go would be with one of the ballistic calculator programs which allow you to "plug in" real data.

This, of course, doesn't eliminate the need to practice at different ranges.

Hey montero, Interesting question, but it can lead you into "wounding" Game.

The External Ballistic Tables in the Bullet Manufacturers Manuals and all the fine Ballistic Software only provides "estimates". They just can't take into account all the "external influences" on a Bullet. Way too many to list, but a few are Bore condition, Loading practices, Environmental conditions, the Shooter's experience level in judging those conditions, the Shooters actual Ability, altitude, scope, shooting position, etc.

Those Software or Load Manual "estimated" Trajectories are useful. They will give you a "general idea" of where to expect the bullet to hit on your Target. However, there are situations where they will not be close enough for you to practice at 100yds and then attempt shots on Game beond that distance. Just too many things can work against you.

As the other folks have said, don't shoot at Game beyond a distance you have practiced.

If you want to shoot Game out at 300yds, than you would be wise to find a place where you can practice at 300yds.

------------------
Good hunting and clean 1-shot kills, Hot Core

Another view would be to shoot a caliber that shoots point blank at <300 yards.

Thank you all for your advise. The shooting range where I go, the only one within reasonable driving time, currently has a 300 yard facility and I normally and regularly practice either at that distance or at 200 yds, depending on which gun I am shooting.
The problem is that, due to the demands from an increasing number of hangun shooters who already constitute an absolute majority, 200 yds will be cut off from the rifle range to build several at 50yds, more appropriate for the hand gunners.
I have not started testing actual 100yd point of impact vs predicted and actual 300 yd points of impact, and was wondering what had been your experience and how accurate were, generally speaking, reloading manuals and balistic softwares in this matter.
Thanks very much.
Montero

i have one of the cheap shooting chronoies,a bushnell 600 yard range finder,the oehler balistic explorer,and a 60 acre hayfield that allows 550 yard shots. if you plug all the right info into the computer you will hit so close its scarry. but i still like to shoot to see myself.i mostly just use the info to compare loads to help me decide which load goes with me. my 300 RUM load is point blank at 340 yards with a 6 inch kill zone,and has almost 2000 lbs energy left at 500. knowing where to zero a certian load without having to waste alot of 2 dollar apiece ammo is helpful.

Trajectory can be predicted accurately at that range, if you are sure of the projectile's BC and velocity. Be aware, I have yet to see a box of ammo have the exact velocity on it. The velocity must be verified by a good chrono. Are the predictions going to be exact? No. But they should be more than accurate enough to keep the projectile impacting well into the kill zone, at least as far as elevation is concerned. Of course, on a windy day? But that is common sense. At the more extended ranges things do tend to get squirrely, predictions do fall short of being accurate. But at 300 yards, you're ok there.