What makes a zero move?

H

HeathSexton

Handloader
May 12, 2006
1,209
41
I have went on a bonafide missing spree with my .260 Remington, it's driving me crazy. Missed a couple critters between 125-250yds and figured it was just the loose nut jerking the trigger. I look out today and there is ol'Mr. Groundhawg at about 80yds, perfect. Sneak to the edge of the house, get prone, comfortable, squeeze, watch ol'Mr. Groundhawg dive into his hole??????????? I go check my rifle at 50yds and I am 1" to the right, where I have been missing everything is to the right, I have not had to adjust this scope in years, why now all of a sudden?? Nothing has changed with the ammo or components.


Thanks!
 
Well we know for sure that some thing has changed. What kind of scope is it? What mounting system and rings is on the rifle? I have many other questions but these we can begin with and the guys on this forum can chime in.
 
Leupold Vari-XII 3-9x40, Leupold Bases and Rings, windage adjust rear mount, these have been on since I have owned the rifle, probably 10yrs? 44.8grs H414 120gr NBT R-P Cases Win Primers, powder and primers are from the same lot that as before.


Thanks
 
Could also be the stock. Humidity can cause the wood to swell, changing the pressure point.

JD338
 
I floated it out years ago. I have not added, removed, twisted or turned a single thing on the rifle since I floated it, that was the last time anything was done oher than cleaning. I cleane dthe rifle 40 rounds ago, accuracy seems to fall off after 75 or so.
 
Go out and re-zero the rifle. It could be the scope has been moved internally. Start over - count how many clicks your scope will move windage and elevation and divide it in half and then bore sight and then go back to the range and shoot it and zero it. Then shoot some more to see if it has held zero. I had a Leupold move on me after some years and did the above and it was corrected.
 
How often do you shoot the rifle in question. Have you changed your shooting habbits.
With the gun unloaded and rested well, sight in on something and pull the trigger. Watch the sight picture if it moves to the right as you pulled the trigger try using less of your finger on the trigger.

I have a 270 that I haven't shot in almost a year. last time I shot it I hit exactly where I was aiming. I had no problems hitting pop cans at 250yds.
I took it out a couple of weeks ago and couldn't hit anything. I am pretty sure it was my form not the mounts or scope. I just finished loading for it and am going to take it out again.
I try to get all of my rifles to have the same trigger pull but, with different brands and aftermarket triggers on some, they will always be a little different.
 
Could be the action screws. Before every season I loosen and retighten the action screws and that is with bedded McMillan stocks. Also could be a change in lots of bullets/powder/primers/cases. Or if the ammo has been sitting for a while neck tension could be an issue.Rick.
 
Which Leupold rings and bases? The quick detachables have a reputation for occasionally moving.

The zero moved, but how does it group? Personally I would clean the barrel really well, and see how it grouped. If it takes more then 2 fouling shots before it settles down and prints a nice group, you have bigger problems.

On the loading side, If either of your dies move, it could affect the zero. A change in overall length can change the zero, and as Rick Smith mentioned, a change in the way your sizing die is set can change the neck tension.

Another thing that can change the zero is Father Time. Just the normal expansion and contraction due to changes in temperature on all those joints. Scope to rings, to mounts, to action. Action to stock and barrel. A wood stock can swell, and even if the barrel is still freefloated, changing the tension between stock and action.

Overall, a rifle wandering 2" over 10 years is just not that unusual.
 
You don't shoot with a couple of buddies that get upset with how well you shoot?? Or a kid that wonders what these cool looking little round knobs do when you turn them? :twisted:
 
Thanks for the replies guys, I have not had a chance to shoot the rifle again due to work and weather, hopefully this weekend. I had not thought about the stock swelling around the action, but it has not done that over the last several years? Ammo was loaded in Feb/March, would that make a difference? I wouldn't think so, but I don't know? I put up a pushpin and loaded some snap rounds and squeezed for about 20 minutes the other night, not jumping of the crosshairs, so my form must not be as bad as I thought.

My rings and bases are not the quick detach, just a turn in front, windage adjust rear. The gun still groups great, it was just off to the right. Elevation was exactly where I left it, just off to the right with a nice tight cluster of rounds. Rekon I should down it and clean the hound out of it?

Powerstroke, nope, I don't shoot with those turret turning buddies or kids that wonder what they are. :)
 
Shot today real quick to recheck at 50. Groups were more open than I am used to with this rifle, I ran some solvent and a patch down the barrel and some dry patches. I have golden barrel syndrome, it is coppered up real nice. My guess is this would cause open groups and possibly a zero shift? I looked back at what I have shot and I am over 100rds without a cleaning. I shot a box and a half that I had forgotten about. :oops:


I don't have any copper remover here, but will have some tomorrow.


Thanks
 
One thing comes to mind if you have a coppered bore. Are you shooting Barnes bullets. In a 257 Wby I had The copper was so bad I had to use one of those reverse plating kits 7 times with cleaning in between to clear the copper out. It got so I could barely keep 5 shots on an 8" paper plate at 100 yds. even with Noslers. After I cleaned it out and went back to Nosler bullets it started grouping around an inch again. Different manufactors use different alloys of copper and some rifles are more sensative to it.
Good Luck
Elkhunt :grin:
 
Greg, I've done the same thing with several rifles. Sometimes it will take a week to get all the copper out, but once you do, many an old bore car be brought back to life.
 
Well, I waded in on the copper problem, dang. First few patches were a real deep purple, almost black with copper. It is getting better, getting back after it tomorrow.
 
Well, after cleaning the .260 good, getting the copper out, and shooting the gun, I feel real smart now. The group returned to tiny, apperantly copper fouling will hurt your groups........ :oops:



Thanks guys
 
I've said it before, and I'll repeat it here. I've had excellent results with Break-Free Foaming bore cleaner, as well as the Birchwood-Casey Foaming cleaner. They are easy to use, get out all the copper (and everything else, generally speaking) and have only one drawback. After you use one, you'd better oil the bore pretty thoroughly, and go back in 30min and re-oil it again, maybe twice. The foam removes everything down to the bare steel, and if you have any humidity (which you do, living in TN, which is much like AL where I am) the bore will streak with rust pretty quickly. I keep a can handy, and use it about once a year or so with my rifles. Some foul more quickly than others, so they get it more often.

For reference, I cleaned a 300Wby for a friend who had been shooting a bunch of original Barnes X bullets with this stuff. Before I started, the bore was crusty and green from the long term copper presence. When I finished, it was shiny like new, and groups went from soup can to bottle top sized.
 
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