The Perfect Zero-Point blank range?

1shot1down · 10-22-2005, 03:40 PM

I just read an article "The Perfect Zero" in the Nov. issue of Outdoor Life. I talks about sighting your rifle in so that you will hit the vital of the animal your hunting out the maximun Point-blank range. Example from the article .270 Win with a 130gr Silvertip shooting at a 10" vital the Max PBZ is 352 yards. That has a point of impact at 100 yards of 3.9 inches high. Do any of you sight in for this. Whats your opinion? I've always just held high on targets of longer distance.

Tuffbroadhead · 10-22-2005, 03:49 PM

Thats where I always zero my rifles in, my 308's are zeroed for 325 yards......
Point blank range is explained pretty simple as if a rifle was to be perfectly flat and shot, the bullet trajectory inclines(rises) slightly out of the muzzel and the point blank range is where the projectile crosses the line of the muzzel....

Weapon________approx 162 yd out 7 "high__________________325ys projectile passes line of sight of muzzle_____________falls into dirt...

Ridge Runner · 10-22-2005, 05:38 PM

I use a 5" window for my PBR figures, I don't want the bullet more than 2.5" high, then I either use holdover or click the elevation in depending on which rifle I have at the time
RR

stubblejumper · 10-22-2005, 05:53 PM

I don't want my bullet to be more than 4" high at any point so even though my cartridges have aconsiderablyflatter trajectory than the 270win,I never sight my guns in that high.I sight my rifles in to be 2-3/4" high at 100 yards which provides a zero of just over 300 yards.

TomFromTheShade · 10-22-2005, 07:18 PM

The general rule of thumb for most long range hunters is to sight the rifle in at 3" high at 100 yards. This will let you hold dead on to atleast 300 something yards in most calibers, which realistically is as far as you will ever have to shoot.

skeeter 7MM · 10-22-2005, 11:05 PM

My current load is sighted in for 2 1/2" high at 100 which allows me to hold to 300. Anything further than that I need to make adjustments with crosshair placement. This works much better for me personally than hold over.

However the sight in you chose should match what you'll see in the field. Makes no sense sighting in 3" high if you expect to shoot 0-200! So to steal a fly fishing term you need to "Match the Hatch"!

mistahmojoryan · 10-23-2005, 11:24 AM

I sight in 2.5" high at 100yds; that get me out to 300yds with little or no holdover. Having said that, most of my shots are close range so even 2.5 is overkill and I doubt I would take a 300yd shot anyway.

2.5" high @ 100yds is just a good rule of thumb to me. Less may even be better but more would just increase my probability for error.

1shot1down · 10-23-2005, 05:56 PM

Thanks for all the input. I shoot a 270 Win for my deer gun. I think I will adjust to the dead on at 300 yards rule because most of the deer that I hunt are taken in that 200-300 yard range, granted I would prefer closer but that is what the praires of ND offer us.

JagMagMan · 10-24-2005, 01:44 AM

Quote:

ORIGINAL: Tuffbroadhead

Thats where I always zero my rifles in, my 308's are zeroed for 325 yards......
Point blank range is explained pretty simple as if a rifle was to be perfectly flat and shot, the bullet trajectory inclines(rises) slightly out of the muzzel and the point blank range is where the projectile crosses the line of the muzzel.

Wrong! First of all bullets do NOT rise!
Secondly, "Max Point Blank Range" for a given caliber and load "is the maximum range, at which the bullet is either higher, or lower than the line-of-sight, aiming point"
For example, if you use a 3" MPBR, and the MPBR is 325 yards, it means that if you aim "dead on" (line of sight,) your bullet will never be more than 3" higher, or 3" lower than theline of sightaiming point out to 325 yards.
Theoreticly, eleminating the need for "hold over" out to the max range!
Personally, my shots are hardly ever that long, so I usually sight in 0-1" high @ 100 yds. I don't like to hit 3" high on short range shots!

zekeskar · 10-24-2005, 01:34 PM

Quote:

ORIGINAL: JagMagMan

Quote:

ORIGINAL: Tuffbroadhead

Thats where I always zero my rifles in, my 308's are zeroed for 325 yards......
Point blank range is explained pretty simple as if a rifle was to be perfectly flat and shot, the bullet trajectory inclines(rises) slightly out of the muzzel and the point blank range is where the projectile crosses the line of the muzzel.

Wrong! First of all bullets do NOT rise!
Secondly, "Max Point Blank Range" for a given caliber and load "is the maximum range, at which the bullet is either higher, or lower than the line-of-sight, aiming point"
For example, if you use a 3" MPBR, and the MPBR is 325 yards, it means that if you aim "dead on" (line of sight,) your bullet will never be more than 3" higher, or 3" lower than theline of sightaiming point out to 325 yards.
Theoreticly, eleminating the need for "hold over" out to the max range!
Personally, my shots are hardly ever that long, so I usually sight in 0-1" high @ 100 yds. I don't like to hit 3" high on short range shots!

I just wanted to clarify what JagMagMan said about the bullet rise - since I was under the misunderstanding myself until someone explained it to me (at which point I said DUH!).

As he said, the bullet doesn't "rise" out of the muzzle. Bullets can only drop from the line of the barrel because of gravity. What you are doingis actually aiming the bullet up in the air a tiny bit. So in that sense, the trajectory does indeed goe up, then down from your line of sight, but does not rise from the line of the barrel.

This is what you do when you adjust your scope to hit zero at say 200 yards. To do that, you need to shoot upward a little so when it drops it hits zero at that point. The same reason why when you throw a ball, you loft it. Even a "fastball" has a tiny bit of loft out of the pitcher's hand.

Yourscope is aiming straight at the bullseye at 200, but the barrel itself is pointing slightly upward. The barrel and the scope are not pointing in exactly the same line. If your barrel was aiming straight at the target at 200 like the scope, the bullet would hit below zero because it drops.

In the arc the bullet makes, it will cross "zero" at two points, usually one pretty close in (e.g. 25to 50 yards) and one further out (e.g. 200 or 300 or something).Between the two zeros, it will hit targets at various places above zero. Beyond the far zero, it will continue downward, and begin to hit the target below the bullseye. Your "point blank" range is how far you can go out with acceptable bullet drop and still be in kill zone without making any aim compensation. For a deer, a 2-3 inch rise and drop is no problem. For a moose, you could probably be fine with twice that much.