Switching bullets effecting zero?

[BK6x47L]

Shooting different manufacturers bullets without cleaning the fouling will cause impacts to be off for 5 to 10 rounds until the new fouling is laid down. Not a good idea to switch bullets without cleaning. Had you continued to shoot, your zero should have walked itself back in.

 

[sea2summit]

Not to be harsh-- you are shooting at 800-1000 yards and not only dont realize but expect both 190 nosler and 215 bergers to hit the same spot without adjusting your scope zero? Something seems amiss, or I'm misunderstanding

Yeah^

Not sure if OP is serious.

 

[T3ninja]

Yeah^

Not sure if OP is serious.

Yeah, I'm serious, not sure you read the OP... or any of my other ones .

 

[codyadams]

Yeah^

Not sure if OP is serious.

Go ahead and re-read the original post, and read the rest of the thread, and you will understand what he is saying.

 

[LaHunter]

Light change can easily cause this.

Can you explain this? I've not heard of this.

 

[misterc01]

Every different bullet has a different effect.

 

[Slibey]

That's strange, would think that something came loose from torque, 190s fouled barrel or optic screwed up.

 

[T3ninja]

So I shot 2 rounds last night at 460 yards, I'm confident to say the scope is tracking (this far anyway) correctly. I had just a slight R—-> L wind 2-3 mph so I didn't bother holding /dialing. Here's the results and a picture of the target before to show I'm not pulling a fast one .

 

[Hatrick]

I would say your back. Nice shooting. I am still going with different compositions of copper in the barrel.

 

[T3ninja]

Thanks. I think I'm still going to redo all of this next week ...then we will all have an answer to this specific situation, and maybe learn something I hope

 

[User4302021]

Can you explain this? I've not heard of this.

The air is a reflective medium which light passes through. It has mass, it has refractive properties, just like glass...A change in light angle changes where you percieve the target to be.

It is an optical effect, it doesn't change ballistics at all...it changes the point of aim, because the target appears to be in a slightly different place than it was an hour ago.

Changes of .2-.4mil (.6-1.3moa) are extremely common. In extreme cases (for instance, shooting down into a shadowed valley, facing the sun low on the horizon), I've seen as much as 1mil (3.5moa) change.

Without being there it is impossible for anyone to say that is what it was. However, it might be repeatable if you shoot again at the same place under similar conditions and time frames.

 

[IHFarmer07]

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.

Been there done that the other day, I have been shooting 147eldms in my 6.5prc for a while but the other day I got the federal 130 terminal ascent bullet and I started to do load development without cleaning the barrel completely.......I found out that I'm going to have to do this above^^^^^my velocities where higher than advertised but everything seemed fine otherwise, although there was a time or two where my pressure obviously was on the edge because I was getting that extra "click" ppl talk about when extracting the case, (so keep in mind for safety sakes, clean your barrel before switching bullets), now back on topic, so I loaded more in my "nodes" and my velocity's where way down from where they should've been in the powder charge, so @Winkfish is on the money, I've heard about this before just never seen this personally.......they say the same for changing powders and primers also but I think I'd just remove powder fouling for those, I think, idk, I guess when in doubt, clean.

 

[LaHunter]

The air is a reflective medium which light passes through. It has mass, it has refractive properties, just like glass...A change in light angle changes where you percieve the target to be.

It is an optical effect, it doesn't change ballistics at all...it changes the point of aim, because the target appears to be in a slightly different place than it was an hour ago.

Changes of .2-.4mil (.6-1.3moa) are extremely common. In extreme cases (for instance, shooting down into a shadowed valley, facing the sun low on the horizon), I've seen as much as 1mil (3.5moa) change.

Without being there it is impossible for anyone to say that is what it was. However, it might be repeatable if you shoot again at the same place under similar conditions and time frames.

Appreciate the explanation. Now my next question is: How do I anticipate this or predict this? I'm assuming when the sun is low in the sky the refraction 'illusion' would be greater?

 

[Ranger Rick]

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.

I thought "getting lucky" only applied to horseshoes and the bedroom Great discussion - I continue to learn from LRH