Mounted a 3.5-15x56 on my 6PPC benchrest rifle today to check MOA adjustments and repeatability. Zeroed rifle at 100 yds, slightly variable wind from 6-7 o'clock .5-2 mph. Drew a 48" line up from aiming point with a level. Fired two shots and the little diamond in a 1" orange dot was gone. Clicked up 10 MOA and fired 2 more one cut the line and the other was touching just left. Clicked up 10 more MOA and fired 2 more one on each side of line. Clicked up 10 more MOA and fired 2 shots one on each side of line. Clicked down 10 MOA and fired one shot right in with last 2. Down 10 MOA fired 1 shot right in with those 2. Down 10 more and that shot was in orange dot. Dialed up 10, 20 and 30 and fired once at each and those all landed in their respective groups. Dialed down 30 and right 5 MOA and fired a shot. Dialed left 10 MOA fired a shot no hole in paper. Dialed right 10 fired one in the same hole as first. Dialed 10 left fired a shot no hole in paper. Can't figure out what happened to the 2 on the left. It was probably me but if so then that's a pretty bad screw-up. Out of ammo. Gonna clean her up and try it again in a day or two.
Measured group heights to see if they moved true MOA's. First and second groups were both .28" higher than they should have been. 3rd group was .53" higher than it should have been. The group fired for windage was off by .015" but that could be measuring error.
When my new 5.5-22x56 shows up I'll try the same test.
How common is it that adjustments are more/less than advertised? And is it common for them to change more the closer you get to the limits of adjustment range?
Last edited by Trikstr; 12-24-2011 at 10:15 PM.
That is a good test, one that I've done many times. First step is to get a bigger paper! Those bullets hit somewhere, it would be nice to know where. Second, I would run the turrets full range about 20 times in each direction to smooth any burrs on the threads and this also assures that the lubricant on the threads is evenly spread. Be very careful not to force the turret at either end . Most of the time this procedure will correct most tracking problems. I'm not sure why the left group would be off. Most scopes are tightening against the spring when going down or left. That is why the old Best of the West videos show the scope being turned up past the desired range and then back down to it. Most newer scopes includng the NF generally have stiffer springs that eliminate the need to do that. On the groups being a little high, a MOA is 1.047 inches. Did you multiply by 1 ", 1.04" , or 1.047". Take the group height in inches for 30 MOA and divide by 120 clicks and you will have the true click value for your scope!
Phil Conklin.... Shooting Instructor for The Best of the West
I did use 1.047". Gonna try it again today. Paper I used was 18" wide with alittle cardboard left over on both sides. I did find another target from last year where I shot the BOX test with this scope and both shots left of center were there. Since the left 2 were present it must have been me. Box target showed some evidence of canting.
this is a great test, and one that few scopes will pass. if you're only off .53 at 30 moa, you're better than most. and yes, i try to stay 10 moa away from either end of travel in the scope. i've heard many say their scope tracks right on, but they just mean it repeats. i do the same thing, but just shoot 2 groups, one 20 moa higher than the other. they should measure a shade under 21" apart. i have an 8-32 sightron that i've tested 4 times, and it moves the poi close to 22". Allan at sightron wanted scope, tested perfect on his collumator, or whatever it's called, then he shot it and poi was perfect. i don't want to say he's lying, but it's tuff to not believe my 4 tests. would like to hear about others doing this test and how i might be messing up.
i'm going to do this very test today with a viper HS.
Shot again yesterday. Looks like it was me that screwed up the other day.
Right windage was of by -.36" and left windage was +.11"of what they should have been for 5 MOA. Clicked up 10 MOA and fired once, clicked down 10 MOA and then back up 10 fired 1 shot and it was touching the one 10 clicks up. They were 10.375" high= <.095" than 10 MOA.
Which raises another question that might not be appropriate for the optics forum, but I'll raise it any way.
How of you have noticed that different lighting conditions(angle,amount) can change were you're zeroes are on target.
Gonna have buy some more match bullets.
Last edited by Trikstr; 12-27-2011 at 09:01 AM.
Reason: added info
FWIW for high end scopes a lot of times it really helps to run through the adjustments all the way a couple times. This helps lube the mechanics inside. It sounds like this is the real issue. My NF had tracking issue out of the box and I ran through the adjustments twice it now it tracks like a Swiss watch.
"Let glorious acts more glorious acts inspire,
And catch from breast to breast the noble fire!
On valour's side the odds of combat lie,
The brave live glorious, or lamented die;" - Iliad, Book V