refresh my memory....

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quiknot

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i consider myself a pretty good shooter (expert marksman in the USMC)...yet I was unable to zero in my 50cal at 100yds...using 100gm powder / lubed patch / lead ball.....I have a long brass 4x15 scope....the only adjustments I have are the back of the scope for height and the front moves sight left or right....there are no clicks, just have to count 1/4 turns to get it approx

my first shot was 6" to the right and 8" low...so I move the back (height) up and front part of the scope to the right...

my second shot was centered but left.....so I moved the front of the scope left alittle...

thats when everything went bad...

I was not able to re hit the target (18"x24")...I even aimed to the far right and left side and still could not see where I hit....after any 6 shots I ran solvent through the barrel to clean any fouling....

am I not adjusting the scope in the proper directions?....

any suggestions would be greatly appreciated....last ime out I was consistently zero'g on 75yds at a 3" circle...
 
NIGHTMARE ISN'T IT!

First of all, I am not preaching here, just offering what advice I can OK!

Normally with a scope you should treat it as a front site.
To sight in properly there are some golden rules to follow.
Make sure that the scope is secure on the weapon.
Make sure that it is secure in it's mount.
Make sure the crosshairs are horizontal and vertical.
Make sure that the eye reliefe is correct for you.
Make sure that when you shoot you always have the SAME eye relief AND that the weapon is level so the sight crosshairs are always horizontal / vertical.
ALWAYS AIM AT THE SAME POINT ON THE TARGET - NEVER COMPENSATE BY MOVING YOUR POA.
SO - If your shot falls Low and Right you need to move your crosshairs Up and Left or Your shot falls High and Left you move the crosshairs Down and Right - BUT ALWAYS TAKING THE SAME POA ON THE CENTRE OF THE TARGET and NEVER try to move your POI until you can record a consistant group.

I hope this helps.
Duncan
 
Double check that scope mount. Then zero the scope out and start over.
I understand that there are no clicks but you need to find bzo on this thing.
Once you find that data, you should be able to adjust from there. Make sure that you record the number of turns on the adjustment.

A low right round sometimes indicates anticipation of recoil and causes ones shoulder to reflex backwards, pulling the muzzle downward and to the right on right hand shooters.

You probably should shoot in 5 round groups in order to see if you are getting consistent shots before you attempt adjustment of the scope.

Once you got ticked off, it became unlikely that you would do well that day.
 
Incorrect Adjustments

You stated: "my first shot was 6" to the right and 8" low...so I move the back (height) up and front part of the scope to the right..."

IMO, I don't believe that you performed the correct adjustment in this instance, but instead performed the reverse of what was necessary.

Moving the rear sight up moves the impact down. However in the front adjustment, moving the front sight left moves the impact left. This is in reverse to standard rifle sights.
This is because it's a tube, and you have to imagine the tube as a sort of "visual rod" or line of sight that's rigid. When you move the rear of the rod down, the sighting rod will angle further up because the front of the tube is like a pivot point and as stated, the rod is rigid.
Also, with the front adjustment, the impact moves in the same direction as the adjustment you make, unlike with a conventional front rifle sight.
So, you move in the opposite direction in back, and the same direction in front, directly opposite to conventional rifle sights.
(My reply is based on theory and experience with rear adjustable micrometer peep sights.)

Have you ever obtained consistant accuracy before at 100 yards with or without a scope, or is this your first attempt? Your previous 75 yard target sure was admirable. ;)
 
With this type scope and mounts with the adjustments being in the mount, it would be adjusted in the same manner as with "iron sights". Moving the REAR of the tube UP moves POI UP, moving the REAR of the tube Down moves POI DOWN. Moving the FRONT of the tube to the RIGHT moves POI to the LEFT, moving the FRONT of the tube to the LEFT moves POI to the RIGHT. The mounts are generally pretty imprecise (loose), this does not help. Tighten everything, then shoot a group at 25 yards, this will aid in finding the present POI. If it won't group at 25 yards something is still moving. Then adjust it so that POA and POI are the same if the tube is above the barrel, if the tube is side mounted then adjust so that POI is separated from POA by about the same amount as the tube is from the barrel.
This should enable you to be on paper at least at longer ranges. It does not take much movement of the tube mounts to move POI a lot at longer ranges.
Good luck!
 
sundance44s

One thing to add ... i would get it shooting dead center at 25 yards first ..as said ... then move out to the greater yardage.. another thing make sure that the rifle is being held level every shot ..any slight canter to right or left will make a huge difference at 100 yards .. some people use a small bubble level mounted to the flat of a barrel .. just remember a smiggit at 25 yards is a foot at 100 yards .
 
I was going to suggest shooting at the 25 yd range, if your range will let you. Remember the 1000 in range? Its 27 yards. Remember that the point of impact (POI) was about 2 inches (or was it one) below the point of aim (POA) and this was the three hundred yard data.

god.. I can't believe I forgot that. must be gettin senile...

I agree with these other guys and we have all told you pretty much the same thing. Remember to write things down. Make a sniper data book for yourself.
 
Possible, But Not Probable

Mercerlake, While anything may be possible, I respectfully disagree. If you move the back of a rigid tube up, the front of the tube and line of sight goes down since the tube isn't flexible. It's long and rigid. ;)
 
moving the rear of the tube up
will increase the point of impact.
You guys are buttin heads over the wrong words.

If the point of aim is say, 6 oclock, and you raise the sight and sight in again...
where are you going to aim at?

6 oclock, that's where. Changing elevation or even windage doesn't change the POA, only the shooter can do that.

hehehe... you guys...

Raising the back of the upper tube will raise the front of the lower tube in relation to the POI

One way to picture it would be to make the sight steady, in your head, immovable or to rest the front and rear of the scope with the rifle free under it. turn the wheel or whatever to raise the rear sight. (this is equivalent to lowering the weapon) you will notice that the rear drops and the front of the rifle raises slowly by precentage of what the back drops in proportion to the balance of the weapon and the centering of the scope from front to rear.
Raising the front (which you can't in most cases), would drop the barrel.

Its a common visualization problem. Nothing to be upset about. My wife, for example, absolutely CANNOT visualize in 3d. cracks me up. some people can, some people can't. just the way it is.
 
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Sighting In Oddd Scopes - -

Try, once you are on the paper, just doing one thing at a time. For instance, adjust only the horizontal grouping until you are on the proper line above or below the bullseye with a group of at least three shots. Then bring the group to the proper height with the other adjustment.

Back in about '45 I had a weird but fancy little long, skinny scope with external springs that was mounted on a German rifle an uncle had brought home from Europe. That was the way we finally got it zeroed in.

GrayBear
 
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