Scope failed tall target test....🤬

GREATSCOTT!

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Jan 22, 2020
Messages
76
Location
Wetside of WA
I will always check a new scope by projecting the reticle on the wall with a plumb line. Do this using a flashlight directed through the scope from the objective end, three feet from the wall. With the scope secured, you can check the reticle relationship to the turret using a level. You can also check the reticle’s s alignment with the plumb line by dialing elevation. The projected reticle should track with the plumb line.
I use this approach to:
Alignment the reticle to the centerline of the barrel, check action rail alignment, and plumb the scope, I have rarely if ever had to re-adjust my mounts for plumb when verifying by shooting a tall-test target. Scope bases are always bedded to the receiver, and depending on the type of rings, lapped for contact area with the scope tube.
This is the same thing I do. With the rifle locked down solid, Ive never had a scope tracking issue that didn't show up immediately when dialing up the scope's full range of elevation against a reticle projected against the plumb line on the wall.
 

280AI rl

New Member
Joined
Mar 15, 2020
Messages
3
Location
WA
Is it possible your rifle starts shooting right after it warms up? If I read your posts, it seems like you shoot 2 at 100 and then dial up with a slightly warmer barrel? Try starting your test at elevation and dial down. I saw a friend’s rifle do this consistently with his 3rd shot. 1.5” shift.....
 

DocGlenn

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Nov 23, 2005
Messages
109
Location
North Georgia
Is it possible your rifle starts shooting right after it warms up? If I read your posts, it seems like you shoot 2 at 100 and then dial up with a slightly warmer barrel? Try starting your test at elevation and dial down. I saw a friend’s rifle do this consistently with his 3rd shot. 1.5” shift.....
I don't think so. I had made several shots before beginning the test. The barrel was warm, probably even hot. Going to try and take my time next time to watch this.
 

Don Garlow

Member
Joined
Jun 6, 2012
Messages
12
Location
Central PA
So I have a Leupold VX6 on my CA 6.5 PRC. Rifle shoots really well, I’ve got a load worked up that is consistent and I’m feeling good about this fall until the tall target test. When I dial up, I get a 1.5-2” shift to the right. I ran the test 4 times. Made sure the target was plumb with a level, used levels to mount the scope, and even tried rotating the scope counter clockwise (since the shift was to the right). Nothing has worked. No matter what I try, when I dial up, I get a POI shift to the right. I know there are a lot of things that can cause this. I’m using Talley one piece rings for the mount. I’ve remounted the scope twice. I’ve got a NF I’m going to put on it to see if it is the scope or the mounts, or the receiver. Anyone have any other suggestions? Would a bore sighting tool show the discrepancy?? I got the scope from Holland’s with his reticle in it. I’m going to call them on Monday to see what they have to say. Is it possible I just have a bad scope?? Thanks.
Glenn
I have noticed the same problem previously and found that, in my case, it was definitely attributable to the bottom of the cheek piece riding the rear v bag. When I switched the scope to a rifle with out the cheek piece, the scope passed the TTT with flying colors. I previously used my Bushnell bore scope and watched the perfectly aligned vertical crosshair slide straight up the borescope for 80 clicks and then right back down again. This lead me to investigate possible outside influences. I finally came up with the cheek piece solution. Not sure that you'll have the same exact solution but torque does occur when the bullet pass through the barrel and my first indication of the problem was a rifle scope always tilted to the right after recoil. Hope this helps! Oh! By the way; When I eliminated the problem, the horizontal dispersion of my groups was also significantly reduced.
 

jgs8163

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Joined
Sep 27, 2011
Messages
726
Location
Southern Arizona
Docs just need to eliminate each variable 1x1. Start with the easiest
the only things I would bed is women :)
After you “chopped up the scope and rings and threw them in the garbage” and “sold the rifle”? 😉
 

Bob2650

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Joined
Dec 10, 2019
Messages
55
Location
Texas
With all machined items, even the top custom rifles, everything is crooked. Nothing is flat, straight or parallel. May seem perfect but that is only because you are limited in the ability to measure. Lapping and bedding does help.
I retired as the head of a quality control department over a large machine shop. Skilled machinists with good equipment, temperature controlled environment and an unlimited tooling budget can make things to plus or minus a thousandth of an inch but it is a big deal and and there will be plenty of rejects. Trying to machine things to a tenth is extremely frustrating and expensive due to the time involved and high percentage of rejects. Machining to a tenth is easy but picking the tenth and hitting it is extremely difficult.
Lapping and bedding is the accepted way to take care of those machining inaccuracies.
 

uka

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Joined
Jun 27, 2012
Messages
100
Docs just need to eliminate each variable 1x1. Start with the easiest

After you “chopped up the scope and rings and threw them in the garbage” and “sold the rifle”? 😉
LOL you know when it comes to women you need money so there went the rifle :)
 

MontanaJack

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Joined
Jun 11, 2010
Messages
51
Invest in the Wheeler Engineering scope mount lapping kit. It includes two point bars for both 1" and 30mm size scope tubes. Position the pointed ends toward each other. If the points don't touch the bases are mis-aligned and will distort the scope. I've used all brands of mounts. The only mounts I haven't had to lap are Near Mfg (Canada) and Sako Optiloc. Those soft aluminum tubes bend easy. Cost me a nice old Redfield 4-12 rangefinder model before I bought into checking mount alignment and ignoring scope mount mfg warnings to not lap their rings. Wheeler Engineering has provided me great service backup, replacing parts quickly and economically when needed.
 

Bob2650

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Joined
Dec 10, 2019
Messages
55
Location
Texas
Here is a hint for the two bar type scpoe ring alignment gauge:
Do Not store them assembled! Such close fitting parts will rust together very easily.
My Brownells set stuck together while in storage and it required a year soaking in Kroil to get them apart. Thought I had good oil on them but not enough of the right kind, I guess.
No exaggerations, it was at least a whole year. Now I coat them with a waxy preservative oil and store them taken apart in the molded plastic box they came in.
The flat ends do work better than the pointed ends.....
 

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