D.O.P.E. Advice

[NWVeteran]

Looking to get some advice.

Went out today to dial up a new rifle/scope

Caliber: 300 Win

I came out to the range today (max distance 1200 yards)

set my zero and started my dial up. I brought 60 rounds of Norma 180g bond strike ammo.

I set my zero and worked out to 1,000

Once I had my dope I worked back down to my zero with Nosler Trophy Grade 180g accubond.

The Nosler Accubond is the actual ammo I am going to be shooting and hunting with. I figured it would be more cost efficient to get a base with Norma ammo as it is significantly cheaper however, what I noticed was that working back down to my zero my data was completely off and not by a little. For example I was grouping bullseye at 400 with the norma at 7 MOA but with the Accubonds I had to drop down to 5.25 MOA. It was obviously significantly larger differences at further distances.

My question is - are the ballistics really that much different between the 2? Is this normal to see such a difference in ammo? Or are other forces at play here?

 

[mxgsfmdpx]

Did you chronograph both rounds enough to get a good velocity number to use? They are likely quite a bit different and the zero between the two also has potential to be quite different. BC will be different as well and calcs can be off.

 

[NWVeteran]

Did you chronograph both rounds enough to get a good velocity number to use? They are likely quite a bit different and the zero between the two also has potential to be quite different. BC will be different as well and calcs can be off.

I did not bring a chrono with me since I was using factory loads. I figured there would be differences in BC which is why I wanted to reconfirm after getting my data. I just did not think the differences would be as great as they were.

 

[ZipsNLbs]

I believe there is that big of a difference . Pretty hard to develop a dope card with out shooting a few for velocity. If you’re using the velocity on the box . I have noticed that mine has been +/- 150 -200 fps before which could make a pretty good difference at distance

 

[SwiftShot]

First , chrono second your BCs are different way different. One has a BC of .612 while the other is .507. Yes they will be off even at the same speeds.

 

[MarlinMark]

The bullet is the variable in your experiment....

 

[mxgsfmdpx]

I did not bring a chrono with me since I was using factory loads. I figured there would be differences in BC which is why I wanted to reconfirm after getting my data. I just did not think the differences would be as great as they were.

Factory loads absolutely require chronographing. Especially if you’re trying to shoot long range with two different bullets and loads. Going off “the box” can easily be out by over 200 FPS. Also, using the same zero for two different loads doesn’t work. They have the potential to be close to each other at 100 yards, but will likely require a decent amount of scope adjustment for a solid zero.

Shoot 10 shots with each at 100 yards and see what the groups look like comparably. My guess is your starting “zero” is off between the two.

Not factoring in the difference in the two bullets BCs into your calculation will cause significant error in the calc.

Pair that with not actually knowing what your velocity is, I can see how this would be the cause of your discrepancy at range.

 

[MuleyFever]

You really dont need a chrono. I zero at 100 then shoot out to 300 or 400 yards without adjusting my scope. I put the actual drops into my ballistics calculator and that gives me my velocity and drops out to my max distance. Then I just go and verify/tweek my data out to distance.

 

[BRTreedogs]

Do they even zero in the same spot at 100?

 

[Seeknelk]

The bullet is the variable in your experiment....

...also the powder,brass, the primers, seating depth, the velocity and the bc of said bullets. But yeah I agree, the bullet and it's speed and bc are much different.
iF you stick with one load dope could be obtained without a chrono with enough shooting. Make sure your zero is actually a precise zero centered on the bull.
But to Chrono the load will shorten the process to getting good dope so you can shoot a pallet of ammo.
Factory ammo actually requires more shots with my magnetospeed to verify ACTUAL velocity and to see just how large ES or SD it has. It's usually slower, sometimes a lot, than advertised.

 

[Yaremkiv]

Definitely common to see this. Things like powder type and amount, primer type, even neck tension will affect velocity. Then you have the projectile construction itself that affects BC which in turn affects flight and so on. Definitely sight the rifle in to the cartridge you will be using. I know it sucks to do when the cartridge you're using is a premium box of ammo.

 

[Pickettpuncher]

Do they even zero in the same spot at 100?

Most likely, no. And guessing he don’t realize that

 

[NWVeteran]

Do they even zero in the same spot at 100?

No they did not. My zero at 200 was 4 MOA on the Norma and I had to drop down to 1.5 on the Nosler.

This was the first time I brought 2 separate factory ammo loads. Usually I pick 1 and zero and use that ammo exclusively but with the cost of the Nosler my intention was to get a baseline and then tweak and fine tune the Nosler. But when I started shooting over the target even as short as 400 yards it basically became a waste of time shooting with the Norma at all. I ended up having to completely reconfigure my dope

 

[NWVeteran]

...also the powder,brass, the primers, seating depth, the velocity and the bc of said bullets. But yeah I agree, the bullet and it's speed and bc are much different.
iF you stick with one load dope could be obtained without a chrono with enough shooting. Make sure your zero is actually a precise zero centered on the bull.
But to Chrono the load will shorten the process to getting good dope so you can shoot a pallet of ammo.
Factory ammo actually requires more shots with my magnetospeed to verify ACTUAL velocity and to see just how large ES or SD it has. It's usually slower, sometimes a lot, than advertised.

I appreciate the info. I am curious to see the actual differences. I will be back at the range next weekend and am going to verify actual. Like I said I expected and anticipated differences I was just kind of surprised at how large those differences were. But now I am curious to get actual solid numbers

 

[WCB]

Box postings are usually allowed a variance. So box posted speed may be 3000fps but the company may allow 50+/- .... so if they are botj advertised the same you could have an instant average of 100fps off. Different loadings and brass sizeing etc could cause further velocity variance. Plus BCs are quite different

 

[JF_Idaho]

Actual muzzle velocity would be important. Definitely seems strange that the accubonds with a much lower bc would have less drop than the bondstrike with a much higher bc. That would indicate a huge difference in velocity with the same weight bullets.

 

[ZipsNLbs]

Just an example this is from the same box of ammo . Their claim of 2700 fps . My actual in two different rifles

 

[MojaveJim]

If you really want accuracy, probably should clean between different brands of ammo. Different powders sometimes don't mix well & the alloy of the jacket will definitely be different.
BTW the box info isn't often relevant, also you have lot to lot variance.

 

[Marble]

Looking to get some advice.

Went out today to dial up a new rifle/scope

Caliber: 300 Win

I came out to the range today (max distance 1200 yards)

set my zero and started my dial up. I brought 60 rounds of Norma 180g bond strike ammo.

I set my zero and worked out to 1,000

Once I had my dope I worked back down to my zero with Nosler Trophy Grade 180g accubond.

The Nosler Accubond is the actual ammo I am going to be shooting and hunting with. I figured it would be more cost efficient to get a base with Norma ammo as it is significantly cheaper however, what I noticed was that working back down to my zero my data was completely off and not by a little. For example I was grouping bullseye at 400 with the norma at 7 MOA but with the Accubonds I had to drop down to 5.25 MOA. It was obviously significantly larger differences at further distances.

My question is - are the ballistics really that much different between the 2? Is this normal to see such a difference in ammo? Or are other forces at play here?

It is a few things.

Yes ballistics make a difference. Not only th3 shape of the bullet but the speed.

But what most people do not realize is that different loads will have a different zero. A different load can shoot slightly left/right or up/down when compared to another.

Set up at 100 yards with a cool barrel. Shoot 3 rounds of one load into paper. Let the gun cool and shoot another load at the same target. Take note of the difference.

Sent from my SM-S918U using Tapatalk

 

[ZipsNLbs]

I appreciate the info. I am curious to see the actual differences. I will be back at the range next weekend and am going to verify actual. Like I said I expected and anticipated differences I was just kind of surprised at how large those differences were. But now I am curious to get actual solid numbers

If you don’t have a chrono I’d recommend the magneto speed . It will shift your poi but works great for getting velocity numbers . When making a load I’ll do 5 round ladders 3 for group with out the chrono on the barrel and 2 for velocity .