Line of Sight - Line of Bore Qn.
#11
Nontypical Buck
Join Date: Aug 2006
Location: Rivesville, WV
Posts: 3,192

I am not exactly sure what you guys mean by angle?? there is no inherent angle built into a scope to allow the line of sight to cross the trajectory twice.
A scope can easily be adjusted to only touch the line of trajectory once, or cross it twice.
First off the bullet never rises. The angle comes from two variables.
Lowering the scope to cross the trajectory-the same way you can raise it to be above the trajectory.
Mainly the angle comes from the fact that trajectory has an ever increasing trajectory curve. Or in other words the farther the bullet gets from the bore-the greater the "bullet drop". This additional drop is what causes the bullet to cross the "line of sight" at either a close distance with a slow cartridge or farther out with a faster cartridge.
IMO what got you thinking about this was the post you had on the Encore base being tilted downward because of the barrel taper(with the longer base). IMO that post was erroneousbecause the base is NOT pointed downward becuase of barrel taper. I think that guy just made that up. Tom.
A scope can easily be adjusted to only touch the line of trajectory once, or cross it twice.
First off the bullet never rises. The angle comes from two variables.
Lowering the scope to cross the trajectory-the same way you can raise it to be above the trajectory.
Mainly the angle comes from the fact that trajectory has an ever increasing trajectory curve. Or in other words the farther the bullet gets from the bore-the greater the "bullet drop". This additional drop is what causes the bullet to cross the "line of sight" at either a close distance with a slow cartridge or farther out with a faster cartridge.
IMO what got you thinking about this was the post you had on the Encore base being tilted downward because of the barrel taper(with the longer base). IMO that post was erroneousbecause the base is NOT pointed downward becuase of barrel taper. I think that guy just made that up. Tom.
#12
Nontypical Buck
Thread Starter
Join Date: Mar 2004
Posts: 2,445

You're right, there's nothing built into a scope to create the angle. The angle needs to be adjustable to allow for different applications.
I disagree that a bullet can cross the line of sight only once. If it crosses once, it must cross again further downrange, assuming it doesn't hit anything of course.
True, bullets don't "rise", they only fall away from the line of the bore. That is the trajectory. But, in order for it to be possible for the bullet to hit the target, it must be fired at an upward angle in reltion to the liine of site. The line of the bore and the line of sight intersect at some distance downrange, say around 25-35 yds. That's why most people take a few shots at 25 yds when a new scope is installed. If you hit dead on at 25 yds, you're on the paper at 100.
Changing the heightof the scope in relation to the bore, say with low or high scope mounts, does change the angle that must exist between the line of bore and the line of sight, but not much.
I disagree that a bullet can cross the line of sight only once. If it crosses once, it must cross again further downrange, assuming it doesn't hit anything of course.
True, bullets don't "rise", they only fall away from the line of the bore. That is the trajectory. But, in order for it to be possible for the bullet to hit the target, it must be fired at an upward angle in reltion to the liine of site. The line of the bore and the line of sight intersect at some distance downrange, say around 25-35 yds. That's why most people take a few shots at 25 yds when a new scope is installed. If you hit dead on at 25 yds, you're on the paper at 100.
Changing the heightof the scope in relation to the bore, say with low or high scope mounts, does change the angle that must exist between the line of bore and the line of sight, but not much.
#13
Nontypical Buck
Join Date: Aug 2006
Location: Rivesville, WV
Posts: 3,192

ORIGINAL: HEAD0001
A scope can easily be adjusted to only touch the line of trajectory once, or cross it twice.
A scope can easily be adjusted to only touch the line of trajectory once, or cross it twice.
#14
Nontypical Buck
Join Date: Jan 2008
Location:
Posts: 1,408

ORIGINAL: HEAD0001
IMO what got you thinking about this was the post you had on the Encore base being tilted downward because of the barrel taper(with the longer base). IMO that post was erroneous because the base is NOT pointed downward becuase of barrel taper. I think that guy just made that up. Tom.
IMO what got you thinking about this was the post you had on the Encore base being tilted downward because of the barrel taper(with the longer base). IMO that post was erroneous because the base is NOT pointed downward becuase of barrel taper. I think that guy just made that up. Tom.
The truth is, you know nothing of the situation and are relying solely on assumptions. Assumptions with no basis in either fact or experience. When you actually own or have ever mounted a scope on one of the guns in question, come back and play. You "think" I made that up, just like you "think" you know everything about the mounting surface of TC guns without ever having worked with one.
Ever notice how you can crank the elevation on a scope from top to bottom and the reticle always appears the same? That is because it is. It is permanently etched, unchanging, on the internal glass. The horizontal crosshair never moved with relation to the vertical crosshair. This piece of glass is mounted inside an internal tube that move up or down, left or right, as you crank the turrets. When the tube hits the side of the turret, you run out of elevation or windage. This is why a 30mm tube has more adjustment than a 1inch tube. The scope can be then mounted parellel to the bore, yet you get the angle because of the angle between the INTERNAL tube and the barrel.
I think some people get confused when you say "the bullet never rises". It depends on your point of reference. If you say "the bullet never rises with reference to the line of the bore", you are correct. But if you are the shooter, the bullet indeed rises above your line of sight to the target because the bore will be angled up to account for the drop. Battleships arc shells a few miles in the air en route to target, so with relation to the ground they certainly rise. But they never rise above a line drawn straight out of the bore.
#18
Fork Horn
Join Date: Mar 2008
Location: Kitchener Ontario
Posts: 245

You can indeed adjust the scope so that the bullet only rises to the line of sight once. This is not reccommended because it limits your effective "aim, shoot and don't worry" zone. If you adjust so that the trajectory intersects the line of sight at 25 yds (approx) rises above and then falls back through the line at around 100 yds, you will be about 1 1/2 in high at 60 yds and 2 - 3 in low at 150 yd. If your hold is steady you have 150 yds of worry free shooting. If you adjust to only touch the line of sight once, that will be around 40 - 50 yds. by 100 yds yo will be 3-4 in low and at 150 6-8 in low. Your worry free zone is now only about 80 yds. After that the ball- bullet falls like a stone and you have to think and adjust your point of aim.
#19
Nontypical Buck
Join Date: Jan 2008
Location:
Posts: 1,408

ORIGINAL: Semisane
Now, now, Spaniel. We like to play nice on this forum. You can make your point without being offensive. [:-]
Now, now, Spaniel. We like to play nice on this forum. You can make your point without being offensive. [:-]
#20
Nontypical Buck
Join Date: Feb 2003
Posts: 3,092

Some bases are pointed down deliberately - I think rarely would you have one pointed up
(all with respect to line of bore). Picatinny rails can be had with varying minutes of offset for many bolt action and black rifles (well, really I don't care what color they are
). It would be nice if there was such flexibility in buying bases for muzzleloaders. A common problem nowadays involves scopes running out of upward adjustment before 100 yard zero is reached with the bp gun. Leupolds tend to have limited adjustment ranges compared to several other brands and are often involved when such problems arise. Be nice if a guy could just determine what offset is needed to get a scope to its optical center, then order accordingly. Shimming sux.
But that would be far too much to ask of the gun industry. Nowadays one is lucky to get a rifle with iron sights that actually work well on the rifle.


But that would be far too much to ask of the gun industry. Nowadays one is lucky to get a rifle with iron sights that actually work well on the rifle.
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