Linear Point of Impact Shift Issue

[kmk1012]

At the range with my TC Compass 22-250 sighting in my new scope and had a reoccurring issue with point of impact. Four different brands of ammo, warm barrel, same results. First shot would be high and left, next would be closer and the third or fourth shot would be about where it should have been. Could a muzzle break cause something like this? I was shooting off sand bags with a rock solid table (set in cement).

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[Joe13]

Scope not set solid?

Bad scope?

Break in on the barrel?

 

[Boboclown]

If everything is on solid then its due to heat. As a barrel heats up it will cause stringing. This is more likely in lightweight barrel. Yes, even bolt actions can string as a result. Faster a round is, faster the heat up, weather is another factor.

 

[MrMillspecer]

It looks like the barrel is moving as tempratures increase or it may be touching on your stock somewhere. Is it free floating ?

 

[DirectDrive]

If everything is on solid then its due to heat. As a barrel heats up it will cause stringing. This is more likely in lightweight barrel. Yes, even bolt actions can string as a result. Faster a round is, faster the heat up, weather is another factor.

This ^^^
Looks like heat and possibly a non-floated barrel.

Prove it out by waiting 3 minutes between shots.
If the group stays tight, then it's heat.
You can improve performance by floating the barrel (if it is not already floated).

 

[kmk1012]

I'll try the three minute between shots next time out. The barrel is not touching the stock anywhere. This is all good advice, thank you.

 

[DirectDrive]

View attachment 465716 View attachment 465715 At the range with my TC Compass 22-250 sighting in my new scope and had a reoccurring issue with point of impact.

So was it OK before the new scope ?

Could a muzzle break cause something like this? I was shooting off sand bags with a rock solid table (set in cement).

Have you added a muzzle brake or was it factory installed ?
I just looked and it appears that it comes with a thread protector.
If you added a brake and over-torqued it, this could have an adverse effect on accuracy.

Just a couple of possible clues from the OP.

 

[Boboclown]

Even if the barrel is floated a thin barrel can still have vertical stringing. Floating may help it, but won't eliminate it.

The following questions should be asked:
How much time was there in between shots?
Are you getting a consistent cheekweld?
Is anything loose?
Was it bedded improperly?

As well as a few more. A lot of variables are at play.

 

[MrMillspecer]

Or was there any wind or gusts ?

Did you drink coffee or Mountain Dew before shooting ?

Do you have tremors ? Or between drink shakes ?

 

[kmk1012]

So was it OK before the new scope ?


Have you added a muzzle brake or was it factory installed ?
I just looked and it appears that it comes with a thread protector.
If you added a brake and over-torqued it, this could have an adverse effect on accuracy.

Just a couple of possible clues from the OP.

The muzzle device was put on previously when it was grouping decent. Yes, this is/was a new scope. As far as timing goes, I'd fire a three or four shot group with about a minute between shots and several minutes between groups. I'm almost thinking it could have been my hold. I merely had the rifle resting on the bags and planted into my shoulder with just one hand for trigger. This method has given superb results with other rifles in the past but maybe not so much with my current one.

 

[Member 5605]

Vertical stringing is from barrel heat. I've seen them walk up in a straight line.

Left to right: wind or shooter error.

 

[DirectDrive]

Vertical stringing is from barrel heat. I've seen them walk up in a straight line.

Left to right: wind or shooter error.

I had one rifle heat stringing, walk off to 1:00 in a tidy pattern.
Depends on where the muzzle is when the bullet exits.
As you may know, the muzzle moves in a tiny circle in reaction to the bullet hitting the lands.
Newton's 3rd Law of Motion
In my case above, the barrel would bump the stock at a certain place when hot.

 

[Simonpie]

Also pay attention to how long the round is in the chamber before firing. As the powder picks up heat, it will burn faster. So waiting a minute between shots with the action open can be different than waiting a minute with a round in the chamber.

 

[Goosebrown]

Do you have tremors ? Or between drink shakes ?

I drink continually while shooting to reduce the shakes but by the end of the session the giant bats usually attack me and I pass out.