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warbirdlover
October 16, 2012, 04:23 PM
I've been mounting scopes for almost 50 years so I know how to properly do it and what to look for if there's a problem. Or so I thought.....

My brother's Model 70 Winchester lightweight won't hold zero. I think it almost has to be a scope issue but here's what we checked.

1. Action screws are properly tightened.
2. Scope bases are tight.
3. Rings to bases and scope to rings are tight.

Rifle has always shot reasonable groups (about 1" to 1-1/2" at 100 yards) with factory ammo and nice groups with handloads. This used to be my rifle so I know it well.

The scope is an original Nikon (now called Monarch) that I bought 20 years ago and payed as much as the highest comparible Leupold scope. The Nikon was clearer and when adjusting it 1 click moved it in the proper direction 1/4" at 100 yards. Always. Now I move it and it impacts far more then what I moved it and when moving it back will go to a different point of impact.

So I think the old scope has finally bit the dust but maybe someone in here can give me something else to think about. The crosshairs look normal. Brother has already ordered a new Nikon scope and rings for it.

Metal god
October 16, 2012, 04:57 PM
when adjusting it 1 click moved it in the proper direction 1/4" at 100 yards. Always. Now I move it and it impacts far more then what I moved it and when moving it back will go to a different point of impact.

Seeing how you know the scope and the rifle . You have checked to make sure the mounts are tight . Not to mention your years of experience . I think you got it right . Sounds like there is something up with the scope . Did you try the old tapping on the knobs to reset the reticle . I've always loved that theory . I'll lightly tap the scope cus the recoil of the 30-06 is not enough :D

jimbob86
October 16, 2012, 05:01 PM
So I think the old scope has finally bit the dust

Sounds like it to me.

warbirdlover
October 16, 2012, 05:46 PM
Did you try the old tapping on the knobs to reset the reticle . I've always loved that theory . I'll lightly tap the scope cus the recoil of the 30-06 is not enough

Should have thought of this. But it's a mute point now. Brother bought a new scope.

Daggitt
October 16, 2012, 06:26 PM
He should return it to the guy he bought it from and get his money back ! There is clearly something wrong with it.:rolleyes:

Double Naught Spy
October 16, 2012, 06:28 PM
My shooting buddy, a retired gunsmith, believes in the tapping and/or 1-2 shots for the reticle to "settle."

coyota1
October 16, 2012, 07:11 PM
I don't remember where I learned this, but If I need to go however many clicks to the right, left, up, down, if it requires 2 clicks, I go 4, and go back 2 etc. I've been doing this for a long time, and it seems to work.

BLUETIP
October 16, 2012, 09:28 PM
we call it back lash. more of a reference to a lathe or mill, still holds tru with anything that moves.

10-96
October 17, 2012, 01:31 AM
Backlash- I used to do that. I have no clue when, or what made me forget about it. Funny when something comes along and jogs a guy's memory.

Big Shrek
October 17, 2012, 02:13 AM
Mute means can't speak...
http://languagerules.wordpress.com/2006/09/25/moot-point-not-mute-point/

A MOOT Point - An issue regarded as potentially debatable, but no longer practically applicable as it was solved by prior action.

Sorry, my mother was a High School English Instructor...some things get stuck in your head...lol

hooligan1
October 17, 2012, 07:03 AM
My son and I went to the range yesterday to test some loads for his rifle, so I took my 111, 30-06 with the Leupold 3.5-10x40 TT on it. It shot right where it was supposed to, three inches high dead center, and this is how I mounted it.
1. First I zeroed the scope so that the reticle was centered in the scope.
2. I always use Leupold rings and bases, so I cleaned the screws with alchohol and added blue locktite to the threads and torqued them properly down to the barrel and reciever.
3. I set my ring bottoms in place, using the proper wrench for the front ring, and centering the rear ring, but I leave the rear ring screws loose for now.
4. I use ring alignment bars from the Wheeler scop mounting kit, and the align front and back rings and tighten up rear ring.
5. I'll use the lapping bar for the appropriate size rings ie, 1 inch or 30mm, and lap the rings until I have a 100% contact surface for my new scope. Also I clean all the lapping compound out of my rings.
6. I gently lay the scope into the rings and cap them, leaving them loose for now so we can plumb and adjust the scope for relief.
7. Once the relief is adjusted I remove front cap from front ring and clean screws with alcohol, and add a drop of "blue Locktite" to the threads and return the cap and screws to the front ring, and tighten lightly for now, and repeat process for rear ring.
8. I torque the ring screws as per Leupolds recommended torque setting.
9. I take it to the range and set target at fifty yds and get it on paper, then move out to 100 yds and zeroe the scope to my zero.

My scopes don't come loose, hopefully this will help anybody needing to do this job properly.:)

warbirdlover
October 17, 2012, 10:15 AM
Thanks hooligan. That's pretty much how I do it too.

Picher
October 21, 2012, 07:37 AM
Note: The (Right) and (Up) directions are where the screws are backed off and the scope uses only spring power to move the reticle. When moving Left and Down, screws move the reticle against springs, so there is less tendency to need tapping to set them.

That's another reason to have a Sight-Vise at the range. Clamp the rifle in with the crosshairs on the center then, while looking through the scope, turn the adjustment knobs. It will soon be apparent if they're sticking and in need of tapping, or just backing off several clicks, then returning to the proper location by screw pressure.

kraigwy
October 21, 2012, 08:33 AM
I had that problem with a Weaver 2.5 X on my 375 H&H Model 70. I put the scope on in '74, zeroed it and no problem.

Then about 5 years ago it wouldn't group. Tried to re-zero...........nothing, no luck.

I fixed it by tossing the 2.5 in the trash and putting on a Weaver K4.

I wont have a scope I have to play games with when I zero. If I click up or down, I want my impact up or down. I don't what to go south X clicks and then north X minus 2 or what ever.

That isn't the way scopes are suppose to work. I certainly don't want to go afield with an "iffy" scope. If I don't have confidence in my equipment, I wont shoot well whether the equipment is on or not.

warbirdlover
October 22, 2012, 10:47 AM
We put the new scope on (Nikon Prostaff BDC) and problem solved. It was the scope. And he can't get his money back from the guy who sold him that scope because that guy GAVE it to him!

Groundhog34
October 23, 2012, 07:49 PM
There is probably something wrong with the 20 year old scope you may try to return it to the manufacturer for repair. I always buy Leupold as their customer service is second to none. Return any product however old and it will be repaired to as new condition or replaced with a new product. No, I am not an employee or paid lackey of Leupold just a satisfied customer.

warbirdlover
October 24, 2012, 11:32 AM
I told my brother to do that (send it back to Nikon). The balls in his court.