I was told that if you sight in a rifle dead on at 25yds that it will also be dead on at 100yds, this doesnt sound right to me someone help please.
Ardodson

Depends on the rifle and round, but yeah, it happens.

What rifle and round are you using?

The one that we were talking about at the time was the .223 that I just bought.

Again, it depends on the round (caliber and load).

At the time you fire the round it immediately begins to drop -- the term "bullet rise" does not mean that the bullet actually rises, but that you aim it high in order to hit an object at ? distance.

So, you're already pointing the gun upward to begin with in order for the bullet to reach a target on its way back down.

Let's say (for argument's sake) that you want to hit a target at 160 yards. You will need to know the ballistics on the round first, then sight it in accordingly. After doing so, your 160-yard bullseye will also be dead center at 80 yards. But it's not because of bullet rise, but because you were aiming high to begin with.

Make sense?

My 308 is sighted in for 50 yards and is still dead on at 100 yards.

Thanks for the help guys.

My grandpa once told me that they sighted guns in the military in at 30 yards. Then you should be about one inche high at 100 and then back on at 200.

That's a good example, Leanardo.

For ardodson, with a 55 grain bullet (for example), if he sighted in at 50 yards, he would be deadnuts at 200 yards - which would be a little over an inch at 100 yards.

Things to consider - if a person really wants to get his rifle "zeroed", is muzzle velocity and bullet coefficient along with the above.

Also, there's charts out there showing trajectory on your round. Good to have it handy.

BTW - I'm gonna move this to the right forum.

I sight my rifle in @ 100 yards, 2" high, dead on @ 200, 4" drop @ 300. I shoot a 7mm Hornady 154 GR Custom BSTP

Depends on the rifle as well, axis of sight to axis of bore difference, etc....fixed sights on an AR are well above the bore, see, same with "see-thru/under" sights, ...

Hard to make a one size fits all statement...

A lot of this misunderstanding comes from the military's "battle sight" that they preach with the M16...I don't remember it all without checking, but it's something about roll the sights all the way down, sight in, then back up 3 clicks...oh well, have to look it up,

Yeah, it is alot more to it than just gun and bullet...

When I got my first rifle I was told about the bullet rising because it was a "high powered" rifle. It took alot of explaining to convince me otherwise. Now, I've done forgot most of it...

I would never ever trust a gun sighted in at 25 yards to be on at 100. My experience has been that they usually shoot 8 to 10 inches high with a scoped rifle when sighted at 25 yards.