Post by: Fishaholic on December 16, 2012, 05:27:12 PM
Post by: Swannytheswan on December 16, 2012, 05:32:05 PM
Post by: bigsads on December 16, 2012, 05:33:16 PM
Post by: Eli346 on December 16, 2012, 06:47:05 PM
Post by: Fishaholic on December 16, 2012, 10:00:47 PM
Post by: JackOfAllTrades on December 17, 2012, 09:03:10 AM
zero at 100, figure at 150 you might be 1" high
WRONG!
The concept of there being a difference or rise in trajectory relative to a straight visual line of sight, on a scoped rifle holds true, but the OP said Iron Sights. That lowers the focal point by more than an inch above center bore of the barrel, which might not seem to be much, but the effects down range are tramendous. If you sight (iron sights) in at 100yds to be zero, then your bullet point of impact beyond 100yds will be below target.
-Steve
Post by: Bob33 on December 17, 2012, 09:08:18 AM
Post by: JackOfAllTrades on December 17, 2012, 01:01:47 PM
A 100 yard zero means a bullet will first cross the line of sight at a distance less than 100 yards. The second zero will be 100 yards in this instance. From that point forward it will be below the line of sight.
Yes and no.. It actually fly's flat enough out to 100yds. While it does arc in flight, I think we're splitting hairs to say that a bullets flight path may actually move above top of bore center before it starts dropping. A heavy slow moving 300gn 44mag would have a more pronounced arc of trajectory relative to line of sight/and barrel bore angle. Lets not make everyone think that the bullet actually rises out of the barrel.
Anyone not ranging their target, could just sight in a 200yd zero with whatever sights, and still have point of impact in an 8" kill zone along the whole distance from muzzle to about 250yds with a 30-06.
-Steve
Post by: Fishaholic on December 18, 2012, 01:16:16 AM
Post by: huntingfool7 on December 18, 2012, 03:50:22 AM
A 100 yard zero means a bullet will first cross the line of sight at a distance less than 100 yards. The second zero will be 100 yards in this instance. From that point forward it will be below the line of sight.
Yes and no.. It actually fly's flat enough out to 100yds. While it does arc in flight, I think we're splitting hairs to say that a bullets flight path may actually move above top of bore center before it starts dropping. A heavy slow moving 300gn 44mag would have a more pronounced arc of trajectory relative to line of sight/and barrel bore angle. Lets not make everyone think that the bullet actually rises out of the barrel.
Anyone not ranging their target, could just sight in a 200yd zero with whatever sights, and still have point of impact in an 8" kill zone along the whole distance from muzzle to about 250yds with a 30-06.
-Steve
Per your drawing- a 100 yard zero with an 30-06 will be dead on at 400? That does not make sense.
With a 100 yard zero, the bullet will cross the line of sight at 17-21 yards, be slightly above the line of sight between there and 100 yards. From 100 yards on, it will be falling.
Post by: JackOfAllTrades on December 18, 2012, 08:26:07 AM
-Steve
Post by: Wazukie on December 18, 2012, 08:37:39 AM
Post by: huntingfool7 on December 18, 2012, 08:55:31 AM
The drawing you posted shows that when sighted in at 100 yards the bullet is dead on again at 400 yards. Per your second trajectory chart with a 400 yard zero the bullet is +7.39 @ 100 yards and +11.16 @ 200 yards.
A good friend of mine is convinced you can hold dead on out to 4 or 500 yards with an aught six. That is only true if your range estimation is a little off :)
Post by: JackOfAllTrades on December 18, 2012, 09:20:39 AM
-Steve
Post by: Bob33 on December 18, 2012, 09:43:45 AM
"Splitting hairs", but here is what my software shows for a 30-06 180 grain bullet going 2700 ft/second at the muzzle with a BC of .4, a sight height of .5 inches, and a 100 yard zero. The bullet first crosses the line of sight at approximately 20 yards, reaches a maximum height of approximately .42 inches at 60 yards, and then drops relative to the line of sight, crossing it again at 100 yards.A 100 yard zero means a bullet will first cross the line of sight at a distance less than 100 yards. The second zero will be 100 yards in this instance. From that point forward it will be below the line of sight.
Yes and no.. It actually fly's flat enough out to 100yds. While it does arc in flight, I think we're splitting hairs to say that a bullets flight path may actually move above top of bore center before it starts dropping.
Yards Drop
0 -0.50
10 -0.22
20 0.01
30 0.19
40 0.32
50 0.39
60 0.42
70 0.40
80 0.32
90 0.19
100 0.00
110 -0.24
120 -0.54
130 -0.90
140 -1.32
150 -1.79
Post by: huntingfool7 on December 18, 2012, 10:42:31 AM
I didn't draw it, I stole it off the internet. Take the line of sight that is drawn out if you want.. Follow the bore! Look down the bore. Look across the top of the bore. The illustration may not be perfect, but it does show the arc of the bullet trajectory with reference to the rifle bore. That simple!Like many things found on the internet, it is inaccurate. If you take the sight plane out of the drawing you can not have the bullet trajectory impact at 100 and 400 yards (and be on at both ranges).
-Steve
Further if you take the line of sight out of the equation, the only place that the bullet is in line with the barrel is directly in front of the barrel. The bullet will impact low at 100 yards then continue to drop from there. Ending about 24" low.
The higher your sights are above the bore, the flatter shooting your rifle will appear on dropping chart.
I am very comfortable with admitting when I make a mistake. I view that as a personal positive trait.
I notice in your post #5 you state "If you sight (iron sights) in at 100yds to be zero, then your bullet point of impact beyond 100yds will be below target.
-Steve"
I wonder if we're viewing different parts of this thread. Post #5 is an accurate statement. I have been looking at and referencing the posted trajectory chart that shows the bullet impacting dead on both at 100 and 400 yards. Don't know what cartridge that refers to but it's not an 30-06
Post by: JackOfAllTrades on December 18, 2012, 12:28:15 PM
Fine! I've removed the graphic if it is too confusing. What I liked about the graphic is that it depicted the angle of the bore relative to getting the bullet path enitial arc to zero at 100yds. Your visual sight plane does impact or pass through the arc two times. This isn't rocket science.. And it ain't my first rodeo.
The OP has stated that he'll just sight in at 200yds.. Lets leave it at that.
-Steve
Post by: huntingfool7 on December 18, 2012, 01:36:37 PM
Post by: Fishaholic on December 18, 2012, 01:51:49 PM
Post by: Bofire on December 18, 2012, 04:18:47 PM
Carl
Happy Ho Ho and Merry New Year!
Post by: huntingfool7 on December 18, 2012, 04:52:25 PM
Post by: BULLBLASTER on December 19, 2012, 11:20:14 AM
:sry:
Post by: Bofire on December 19, 2012, 08:19:17 PM
In other words never look thru a right handed optical device left eyed which of course cannot be done with open sights and always consider the axis of the earth and direction of orbit. ( hint the sun rises? in the East.)
Sincere God of all Knowledge Worth Nothing (knowing)
Carl
Post by: Arnbo on December 28, 2012, 09:33:13 AM
You always get every angle and every possible answer.
You guys are the best! I have learned a lot in the short time of being a member.
Happy New Year......
Arnbo