Scope height?

popper43 said:
HM1996 got it right, except bullet path is a downward arc. JBM or others won't calc THIS PROBLEM correctly.
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Sure it will. If you know the bc, velocity and line of sight height and input the numbers correctly it will figure the bullet path. Takes advantage of the trajectory. Lets you figure out MPBR etc.
 
If you have used a bore sighter you see the 25 yard offset(bullet impact below scope reticle center) increase when the scope height increases. What also occurs is a change in distances(2) at which the line of sight and bullet flight intersect.
 
Just to be fair and all things equal. I'm going to load 10 rounds just like what I used the first time out. A few just to see what raising the scope a half inch did to the impact, high or low. Then what ever is left I will use to sight back in with. We shall see!
 
You're probably well aware of this "one shot" zero method, Bill, but for anyone who is not familiar with it, all you need is an adjustable rest or someone else to hold the rifle steady on the bags.
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I am a fan of shoot a group and move the center of the group. Too many times ive chased around a zero by trying to sight in one shot after another when the rifle isnt grouping them well.

I get on paper, which is shooting 2" low at 10yds on a paper plate. Then i go shoot a sight in target (ones with 1" squares) at 100yd and simply move the group of 3-5 to the center using math.
 
3 shot for years, but have evolved to above method. Pretty much always can call the shot and shoot another if I suspect it might not have been good. My biggest problem is without a clamping rest, very difficult to hold rifle steady on bags and adjust scope without moving it a tad.
 
Its very hard to hold it steady and move the crosshairs, ive done it many times.

Knowing how many inches your group is off is simple math to move it it to zero.. with the squares you can do it from the bench. If its 2" left and 1" high thats 16 clicks right and 8 clicks down on a 1/8" scope. MOA turret might require one less click. Only works if your scope is mounted square/level through.
 
hm, I've used this method for years. With an AR a bore sighter is pretty much useless. Most times I look through the bore and do the best I can to get the scope and bore together, fire a shot, then move elevation and windage to the bullet hole, usually gets me really close. I may have to tweak it a little. I have a friend that wastes more ammo sighting in than anyone I've ever seen. He fires multiple round getting elevation then more rounds doing the windage. I ask him why he doesn't adjust both and he says its just the way he does it. Well.....OK.
 
I have a Kennedy machinist box that I rigged up to carry to HP matches. Carried a lot of extra stuff to maintain club M1's + everything including my rifle sights & ammo to shoot a regional match coarse (88 + another 10 alibi rounds just in case). Mounted a carpenter's vise to hold my rifle when not on the line. Can't shoot off of it, but would hold rifle steady to adjust scope.
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Also great to hold rifle for cleaning or maintenance in the loading room. I don't always take it to the range but have used that to set rifle up for the one-shot. Usually just try to hold it myself which sometimes requires a 2nd shot.
 
William Suter said:
I have a friend that wastes more ammo sighting in than anyone I've ever seen. He fires multiple round getting elevation then more rounds doing the windage. I ask him why he doesn't adjust both and he says its just the way he does it. Well.....OK.
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:ROFLMAO: Whatever works.

Here's a trick for AR's, Bill.

I have about 20 ft. from my workbench in loading room to the living room wall. Made this bore sighting target for various heights above bore rifles. The AR's usually around 2-2 1/4 above bore, so use center hash, bolt guns usually 1 3/4 use bottom one.

Center "target" in bore and adjust elevation to corresponding horizontal line on target will get you on paper.
Disregard the extra target below as it is a special check for my pet bolt gun drawn up after rifle was zeroed on range to duplicate sight picture. As you can see, bore sighting is not zeroing, but gets you on paper. :LOL:
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I used to have a little prismatic bore sighter for rifles like lever actions or pumps.
 
I had an army surplus one for years, but have misplaced it. Necessity is the mother of invention when I put a scope on an M1 which, by necessity had to be mounted high. Glued small mirror on end of dowel cut @ 45* angle.
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Hard to get picture centered.
 
I have the small colored round stickers on the wall at 20'. Laser w/chamber adapter for most of my rifles, use that to mount scopes. Really helps with the Burris signature rings, to get in the ballpark with correct insert.
 
I went to my buddies funeral yesterday, made for a really lousy day, but was talking with a friend about the scope height on the AR. He says it won't make a bit of difference. LOL, I know better than that. But....Even though we had quite a bit of wind today I still loaded up and went to the club. Wind was blowing towards the target so I didn't think it would effect my bullets enough to worry about. First shot.....3/4 inchs low. Pretty much what I was expecting. Not trying to be a jerk but "I told you so"!!! LOL, just ragging on ya! Thanks for all the thoughts and it was a fun post with lots of opinions but now I know.

Now to start load work and FYI, that riser and new trigger made a huge difference in the way this rifle shoulders and shoots. Accuracy needs a little tweeking but I'm still minute of coyote with the loads I shot today. And I've only got 40 rounds through the barrel.
 
Show us the target and your adjustments. 1.047 inches is 1 moa @ the muzzle that is 0.00349 inches. Missing 0.25 elevation, or you didn't get it remounted the same. You should have been 0.5235 inches low, something is wrong.LOL,LOL.
 
Hey man, I just an old and I mean old country boy and all that high math is beyond my schoolin'. It was about 3/4 of an inch, might have been a little less. All I know for sure is it was low. :)
 


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