Cold bore zero versus (very) Hot bore zero “test”

[HuntHarder]

I have a hard time believing mirage, 5×'d your group. Was it so blurry that you could barely make out the target?

 

[Mike Islander]

Mirage blows my groups up after 7 or 8 rounds. I must have a fan on the barrel or the chamber fan while I reload the magazine to make it to 10 shots. Even doing this the last 2 rounds I am fighting mirage from the barrel. Then I have mirage from the ground to contend with. I am very curious if the people at 5K altitude and above deal with similar issues? I am under 1000’ sea level generally with 70+% humidity. Most shots are between 6 & 10x

I use a length of narrow cardboard resting on the barrel to block mirage. Works decently well.

 

[1000yards]

I have a hard time believing mirage, 5×'d your group. Was it so blurry that you could barely make out the target?

Not at all. The target would get a little blurry from mirage, but I would wait for it to sharpen up before taking a shot.

 

[Macintosh]

I routinely deal with zero-wind conditions on the ranges I shoot at. There is 100% dense forest cover and all ranges are simply a strip of forest thats been cleared 100 or 200 yards long by 40 or 50 yards wide. So you’re essentially in a sheltered trench that blocks all of the wind, which isnt much to begin with. Mirage can and frequently does render the target un-seeable. I usually have to wait for a breath of air to clear the mirage. Any breeze at all makes a massive difference. I have no problem believing mirage could 5x your dispersion if you werent really waiting for it to dissipate.

 

[Redmcx45]

awesome thread with great info!! I'm here to be a sponge and learn.

I'm curious what you guys think about my specific case here. First some details

Rifle- Seekins PH3 in 7mm PRC- SiCo TI can, 22" brl, NF NX6- 6x36- 200-250 rds thus far.
Bullet- Berger EH 175gr. I shot 10 rds @100 yards.

POA is middle of target .First shot in green circle, proceeding 9 remaining shots in purple circle. First shot was cold bore. Remaining 9 shots were in succession with ~15-20 seconds between each round. I am working on basic fundamentals like my trigger pulls, cheek rest etc..

Is it possible I flinched on my first shot then the remaining 9 rounds were better shooting on my part? I'm thinking this is the case but, would like some feedback .

Edit: Zero wind during this string.

1.77" between furthest shots.

 

[nm.otter]

Is it possible I flinched on my first shot then the remaining 9 rounds were better shooting on my part?

What happens if you repeat it?

What kind of front and rear supports are you using? Sometimes the gun can settle down into a bag (or slide back off) after the first shot.

Is the gun suppressed?

 

[WhoGarrDen]

awesome thread with great info!! I'm here to be a sponge and learn.

I'm curious what you guys think about my specific case here. First some details

Is that your first shot after doing a deep clean on the rifle? I just clean the chamber/bolt, and if I'm not going to use the rifle for 2mo+ (unlikely), I'll put a wet patch of OneShot down the barrel. No "cold bore" variance has been observed.

 

[Redmcx45]

What happens if you repeat it?

What kind of front and rear supports are you using? Sometimes the gun can settle down into a bag (or slide back off) after the first shot.

Is the gun suppressed?

Great questions. This happened on Saturday when I was shooting a different rifle (22CM) and only had 10 rounds for the 7PRC with me. I was using a atlas bipod front and a sandbag in rear. I will 100% try and repeat it as soon as I can get back to the range. The gun is suppressed. SiCo Scythe TI.

 

[Redmcx45]

Is that your first shot after doing a deep clean on the rifle? I just clean the chamber/bolt, and if I'm not going to use the rifle for 2mo+ (unlikely), I'll put a wet patch of OneShot down the barrel. No "cold bore" variance has been observed.

Have never done a deep clean on this rifle. Just ran a bore snake through it a few times with a little hopes on the aggressive brass brushy section. Last time I ran a bore snake the rifle was at approx. 100rds.

 

[nm.otter]

The gun is suppressed. SiCo Scythe TI.

If the pattern repeats, try removing the can for a session.