Switching bullets effecting zero?

[aushunter1]

Next time try the same process again but with an already fouled barrel from the onset.

Re zero with fouled barrel then see what happens!

 

[T3ninja]

I'm going to clean it again tonight. I will confirm zero, then make sure nothing changes in the first 8-10 rounds. I can shoot about 460 off the back deck, I'll see if I can duplicate it at closer range.

 

[imyourhuckleberry]

After re- reading your post again another possibility that could affect the impact of your 215 grainers is the time of day your fired your last rounds . You mentioned day and night in your post so assuming day was early and a littler warmer, the air might have been less dense when you started shooting during the day and than you wanted to finish off the "night shooting" your 215 grainers depending on the time span between beginning and end if it was several hours the air temperature could have decreased some, making the air more dense thus affecting your trajectory and accounting for your lower impacts especially at those distance.

The kestrel is only good for where you are but at 800 yards atmospheric conditions can be totally different from where you are. Though you might have felt that conditions were the same where you were I assure you it might not be the same where your target was almost 1/2 a mile away.

 

[WildBillG]

Were the Nosler bullets coayed in any thing. As the coatings could cause a sudden change of impact.

 

[T3ninja]

The temp thing may possibly have something to do with this . However it was steady in the low 60's I can't imagine a few degrees making that much difference. Unless..... a thought just popped into my head as I was typing, the ammo was warm/hot from the trip to the range and I got lucky on the first 3 rounds, and the later rounds wore in fact the "correct" impacts and my data is off.... my shooting position was shaded and cool. Hmmm


No coating on any of the bullets.

 

[Doom2]

Maybe a dumb question, you have dope for 600 and 1000yds but have you previously verified it at 800?

 

[Winkfish]

I have seen this before when I was doing a bunch of bullet testing on a 308. The different guilding metals was changing impacts.

I found that I had to clean the barrel, perform all my testing, then clean again when switching to a new bullet or I see odd behavior as you are seeing. I used boretec copper remover and got it as clean as possible. Then I would shoot 10 rounds with the bullet I was going to test before I did my ladder tests.

Just something else to consider.

 

[Jeffrey Van Zandt]

I'm your huckleberry: I'm comparing impacts only from the 215 Berger, they were spot on for the first 3 shots. Then I shot up some 190 noslers, just for getting my brass back (adg) then switched back to the bergers.

Wildbill: I actually never pulled out the data for the 190's, But I did double check that.

Country: This is what I'm referring to, I'm wondering if anyone else has seen this. Im sure there are, Nosler/Berger. I've heard of different powder causing something like this, but it's all the same powder/lot from an 8 lb jug . I'm going to go again next week and see if I can mimic these results.

different bu;;et lots same with powders if not from the same lot brass all the same temps up down primers differemt lots ect can all make your round hit different

 

[JustMe2]

Absolutely changing bullets back and forth will affect the previous bullets. This is why you always clean your barrel between sessions when changing bullets during load development. Cleaning is common practice when changing bullets.

 

[R2rr]

Quick comment regarding Cody's Ruger Mini 14 'scope killer' comment:
I used to shoot the Mini 14 at my job. I disliked it because the recoil, though light) would kick the sight picture high and left after the ****. Hated that. Come down after the shot and found the sights pointed well left.
It was due the rotating bolt. At rearward travel, the bolt rotates counter clockwise and smacks the stops,kicking your sight alignment.
I suspect that to be Cody's 'scope killer' culprit.
We always used iron sights, so scope killing never was a factor for us.

 

[25WSM]

I would bet that the copper is different on the 2 bullets and is causing the issue. Next time out do the same test. And after you verify the 215s are low again clean the barrel. Put a couple 215s through for foulers and I bet they start hitting where they should. Just a tip is that when you shoot a clean barrel at 1000 yards it will average about 18 inches low on that first shot. Then on the second shot it will be close and the third shot usually is right there. Some barrels take a few more shots to settle in but most are going to settle in 3 shots.
Shep

 

[Steelflight]

Try hanging your tongue out next time.lol

It is curious. I wonder if even the environment changed enough around you. But thats grasping at some long straws. Assuming you have a hefty barrel and its not whipping on you from heat. (Yes you set it down to cool.) There are a dizzying amount of factors to consider.
Good luck

 

[T3ninja]

Ok, so last night I gave it a good cleaning. I'm going to try to do this whole thing again next week.

I fired 3 rounds after cleaning to confirm that the cold and clean shot was within the group, and centered on target ( all at 100 yards) cold/clean included group was .62, discounting the cold clean it was .32... weather isn't good or I'd shoot a little tonight.

Barrel is a 28" proof sendero, so it's not a light profile.

If the weather is better tomorrow I will try it out at 450 tomorrow, and hopefully get to the big range next week! Thanks fellas

 

[User4302021]

Light change can easily cause this.