Wanted to run this by you guys:

Normally, my CBS is 2 clicks up, one click left, then the rifle settles into the zero setting on the scope after one shot. Recently, I've not cleaned the barrel after shooting, applying a thin film of oil that gets patched out before the next outing. Everything has been consistant as far as CBS and zero for 220 rounds.

Today, the CBS was the same, but afterwards, I needed 6 clicks UP to have the rifle at zero at 100 yards. Can the drop be that much all of a sudden? Rings and mounts are tight.

Rifle is a 308, 24" barrel..load is 175 Matchking over VV140...

Thanks,
Charlie

Waldo wrote:Wanted to run this by you guys:

Normally, my CBS is 2 clicks up, one click left, then the rifle settles into the zero setting on the scope after one shot. Recently, I've not cleaned the barrel after shooting, applying a thin film of oil that gets patched out before the next outing. Everything has been consistant as far as CBS and zero for 220 rounds.

Today, the CBS was the same, but afterwards, I needed 6 clicks UP to have the rifle at zero at 100 yards. Can the drop be that much all of a sudden? Rings and mounts are tight.

Rifle is a 308, 24" barrel..load is 175 Matchking over VV140...

Thanks,
Charlie

You're saying your first round (Coldbore) was on target but after shooting "X" number of rounds at various ranges, your 100yd Zero was "6-clicks" low?

What kind of scope?

BTW we don't talk in "clicks" as "clicks" can vary by scope. Please use either Minute of Angle (MOA) or Milradian (Mils).

Leupold M1..one of the old ones

Cold bore shot was the usual one-half minute low and one-quarter minute to the right....the rest of the shots were one and one-half moa low.....

Still trying to wrap my mind around linear vs angular measurements..

was this at the same range you zeroed at, or a different range?

What about weather?
Colder than normal?

I don't think that the issue is related to the cleanliness of your barrel.

I'm leaning a bit towards not having a proper parallax or cheek weld which can offset your POI. Not familiar with Leupold's M1 but I'm sure it gives you the ability to adjust parallax.

AR15barrels wrote:was this at the same range you zeroed at, or a different range?

What about weather?
Colder than normal?

This was at one of the local ranges I go to frequently. I didn't have a thermometer to tell the exact temp, but it was similar what I usually shoot in. There was a rainstorm that passed through the day before though....maybe the barometric pressure was different?

dreka wrote:I don't think that the issue is related to the cleanliness of your barrel.

I'm leaning a bit towards not having a proper parallax or cheek weld which can offset your POI. Not familiar with Leupold's M1 but I'm sure it gives you the ability to adjust parallax.

Thanks...that's one of the things I forget to do at times..

It was consistant....I took one shot at the dots.... noticed it was low and walked away. Came back and shot four more and all five were all the same off vertically and on horizontally.

weather plays a huge difference...When we shot the last WEGC match, I was WAY low on my CBS due to rain

Thanks for the input, guys.

I'll double check my parallax the next time I'm out and come to grips that my weather/temperature sensing-fu is weak.

Try dry firing 25 times before you first shot...

If you clean your barrel the and first few rounds are off that makes since. If you have not cleaned your barrel your CB should be on. Note many believe its a cold shooter not barrel that causes the issues.

Be for any shot to "matter" you must have.

Parallax adjusted
Edge to edge site picture
correct shooting position
good trigger pulling technique
placing the shot in the bottom of your breath
understanding of how DA, temp and wind will effect your shot.

As you can see it's most likely the shooter not the gun or barrel.

264Charlie wrote:Try dry firing 25 times before you first shot...

If you clean your barrel the and first few rounds are off that makes since. If you have not cleaned your barrel your CB should be on. Note many believe its a cold shooter not barrel that causes the issues.

Be for any shot to "matter" you must have.

Parallax adjusted
Edge to edge site picture
correct shooting position
good trigger pulling technique
placing the shot in the bottom of your breath
understanding of how DA, temp and wind will effect your shot.

As you can see it's most likely the shooter not the gun or barrel.

+1 and an Amen to all of that.

Funny how I remember to do all that when I'm shooting by myself but as soon I'm under pressure, everything goes out the window.

264Charlie wrote:Try dry firing 25 times before you first shot...

If you clean your barrel the and first few rounds are off that makes since. If you have not cleaned your barrel your CB should be on. Note many believe its a cold shooter not barrel that causes the issues.

Be for any shot to "matter" you must have.

Parallax adjusted
Edge to edge site picture
correct shooting position
good trigger pulling technique
placing the shot in the bottom of your breath
understanding of how DA, temp and wind will effect your shot.

As you can see it's most likely the shooter not the gun or barrel.

Well summarized checklist..I'll try to incorporate it into the routine