Bizarre Accuracy Problem

[Doug]

I've been playing around with an old Winchester 67A with a 6-21 mil-dot scope.
It likes CCI Mini Mags and shoots them well.
Today at the range I was right on at 100 yards and hitting 1 inch targets from a rest at will.
At 25 yards, I could do 1/2 inch targets easily.
At 50 yards, I am getting good groups, but they are about 2 inches left of the point of aim!
Perfect windage at 25 and 100; 2 inches left at 50.
The scope is adjustable for parallax and I carefully focused it at each range and test for parallax by moving my eye side to side and up and down in the field of view and the cross-hairs did not move on the target.
I would take several shots at each distance and move back and forth between the shooting points and got consistent results.
I am totally bumfuzzled.

One old timer suggested the shooting gods were angry and blowing on my bullets when I shot at 50.
I would prefer a more logical explanation.

Anybody got any ideas?

 

[x10]

couple things,

when you changed to 50 I assume you had to change your position and in doing so did the bags, sling, or contact points with the rifle change, If so a little pressure on the stock can change a lot

scope, did you move the adjustments, is it a quailtiy scope ect. you would have had to change PA, as stated, sounds like you have a scope P/A problem ,

did you make the proper sacrifice to the accuracy gods, if not now you have to find a Clinton to sacrifice on the alter, if you've angered the god's not any normal Democrat will do

 

[Doug]

I tried to keep the gun position on the bags consistent.
At 25 and 50, I shot from the same bench and simply changed elevation position.
I did not adjust the scope; I used one of the mil-dots as the aiming point at the closer ranges.
I moved from the 50 to the 100 yard benches and back 3 or 4 times and had the same results each time.
By P/A problem, I assume you are saying the point of aim changes as the scope focus changes.
Hmmmm, next range trip I'll try finding a compromise focus setting and see what happens.
Thanks.

Any other ideas?

 

[Tombs]

I tried to keep the gun position on the bags consistent.
At 25 and 50, I shot from the same bench and simply changed elevation position.
I did not adjust the scope; I used one of the mil-dots as the aiming point at the closer ranges.
I moved from the 50 to the 100 yard benches and back 3 or 4 times and had the same results each time.
By P/A problem, I assume you are saying the point of aim changes as the scope focus changes.
Hmmmm, next range trip I'll try finding a compromise focus setting and see what happens.
Thanks.

Any other ideas?

Your scope is canted, or at least the reticle.

 

[Doug]

Your scope is canted, or at least the reticle.

Visually, the mil-dot I am using as an aiming point at 50 yards is directly above the the cross-hairs I use as the aiming point at 100 yards.
I use the same dot at 25 and don't seem to be an inch to the left.

 

[top hat 45]

best guess!!!!! i also like minimags for some rifles. try shooting 25, 50, and 100 without adjusting scope at all. have a long enough target to accomodate the drop from 25 to 100. see if results are the same. if no change, just grabbing at straws, change ammo for a test. if no change still i've got another scope to throw on it to continue testing if interested.....daryll

 

[OVERTHEHILLGUY]

I for one believe "The old timer" is right. Proof, e-4s + .3.1416 = 50yds. Reason...I AM that person!!

 

[karl77]

thinking he scope has broken lens(es).

 

[gunman41mag]

Maybe the barrel was hot by the time you started shooting at 50 yards, clean the barrel & shoot the rifle again

 

[Doug]

I got back to the range today.
I tested at 25 and 50 yards and the gun was still shooting to the left. Previously, I had shot bits of clay bird at 25 and apparently they were big enough that I was hitting them on the left edge.
I moved the target to 100 yards and found the gun was shooting to the left.
I adjusted the scope to hit point of aim at 100 yards.
When I moved to closer ranges, the windage was right on.

The only solution I can come up with is that when I was at the range earlier, there was an undetected wind from the left between 50 and 100 yards.
The firing points for the closer ranges are closer to the board fence on the left side of the range than the firing point for the 100 yard distance. I guess it is possible the wind came over the fence and blew the bullets to the right.
So, it was either the shooting gods being displeased, or the wind whistling over the fence from the left, or a really bad shooter consistently pulling every shot almost exactly 3 inches to the right, but only when shooting at 100 yards.

Anyway, today, my old Winchester is putting them right where they're aimed.

 

[BE Mike]

In my experience, unexplained things like these, usually are the result of the loose nut behind the trigger.

 

[Doug]

OUCH!
You're probably right, but, ouch.

 

[BE Mike]

OUCH!
You're probably right, but, ouch.

I came to that conclusion after a lot of first-hand experience
.

​

 

[1911ly]

I had a similar issue last year. I was shooting 3 round groups groups at 100 yards. every group was in a different spot. I thought I knocked the reticle loose because it would not hold zero. I walked out to 100 yards to pick up my targets to find out the wind was gusting from behind the trees a the 100 yard back stop. Next time out it was a calm day and all was well. I was shooting .22lr.