Help Needed with LB3.0 and .338 Bergers

[Eaglet]

I just loaded the perimeters into Loadbase and I now get the same come ups as you do Eaglet. I believe them to be on track and will be shooting again very soon to document this and test new distances.

Interestingly enough, I loaded the same 2705 mv into my Nightforce exbal program using the G1 BC of .891 and it is spot on too at these ranges of 700, 1042 and 1342 yards.

I am focused to make my self use LB so I can build confidence and smoothness with my operation of it. If nothing else, I do feel the spin drift, corialis and wind part of he LB program has something to offer. However I find inputting the wind to be confusing using the number of degrees instead of simply using the clock method. Not to mention if you are at 330* (11:00) and want to return to zero you have to go back all the way arond counter clockwise. Would be nice if it would just cross 360* to 0* again.

I am learning!

Thanks again!

Jeff

I know what you're saying! Keep in mind that you can highlight and just type zero. You don't have to wait on the little arrows to go up and down; if you're at 330 and want zero just highlight it, bring up you screen keyboard and type zero. You're a fighter, you'll develop the confidence, don't worry.

 

[Broz]

Thanks Eaglet and BnG. Got it on the wind direction..


Well for the sake of "wanting to know" I guess I will change and input the new BC of .419. Then adjust MV to see what the new mv is.

I was really having a hard time with one grain loosing 100 fps. Now I know why the 300 smk come ups were so good using 2805 for velocity.

This explains a lot and raises new questions as well.

I had a lost bullet on a large target and wrote it off to my error in shooting. I could be on the verge of the "nose slump" I know the standard lapua is suppose to be fine, but I go up one grain and see pressure.

The future of the bullet? If it is going to change do I want to perfect the load and program just to have to change it soon?

As many may know I am a Berger fan. 100%. But I may want to wait for the VLD and just do this once more.

Jeff gun)gun)

 

[Eaglet]

Yes, I just read it. I think this definatly explains some of my problems and the reason for need to use such a low MV.

I need to think this over here. Not sure what I want to do. I have lots of these on hand but why would I want to spend anymore time and barrel life if the design is to be changed and I would need to start over.

Hmmmmm.

Jeff

You are right on the money!!!!!!!!!!!!!!!

I'm working on the new info.... We need t o remember that before in their testing they confirmed the BC we have been using... Did they? either way
keep the info you have right now because it could be right! Then again you'll have the new info if that does not work!

I really never expected that one!!! LOL but we're narrowing it down!!!

 

[bigngreen]

I was working around the 2750fps range with the new G7 BC but I ran out of battery in my PPC so that was as far as I got.
The earlier data seemed to be a real good match though.
These soft nose Bergers may be the ultimate long range game bullet, terminal performance should be of the chart!!
I'm going nuts not having a 338 to shoot these out of, I'm kinda waiting for Carlock to spill the beans on the 338 Edge + P and if that don't pan out I'll go with a 338 LM Improved. I missed my chance earlier this year on a 338-378 Mark V for 850 dollars with only a half a box of shells through it

 

[Pdvdh]

The only way one could ID MV with drops is if one absolutely has the correct BC entered into the ballistics software, has properly accounted for atmospheric conditions, operates the software correctly, and is a dead-eye of a shot (you pass that last one with flying colors).

The current evolving value of the BC for the .338 Berger Hybrid is a real life example of the flaw associated with identifying MVs based on measured drops. The presumption was that the Berger .338 published BC was correct. Now the presumption is that the original Berger BC is incorrect. Taking a flawed BC value and tweaking the MV in a ballistics program until it matches your drops produces a drop chart that will only be valid at the range and environmental conditions under which the bullet drop data was collected. Because now the input values for BC and MV will both be flawed. Take that drop chart, or the ballistics program with the faulty BC and MV to another set of environmental conditions, and there can be no expectation of correctly predicted dope.

So as inconvenient as this exercise is proving for Broz, it clearly demonstrates my preference to tie down the MV with chronographs during load development right from the get-go. Then when the field drops versus predicted dope inconsistency rears its ugly head, less guessing and speculation is required because the MV is more or less a known value.

I tend to believe if LB predicted dope isn't matching the carefully collected and documented field measured drops, then there's a problem with the quality of the input values entered into the program. And an accurate MV is vital to the whole process. Rant off! gun) gun)

 

[bigngreen]

Would this all be avoided if we would shoot and gather MV data at several different yardages and use the Analyzer feature to calculate the true BC and DC for that particular rifle and bullet. I think this is a valuable feature of Loadbase that may not get used much.
I think that two proven chronographs or one Oehler 35p with the proof channel is the way to go as Phorwath has high lighted in his work with Loadbase.

I was wondering about the accuracy of our predicted trajectory when we tweek numbers and then move to a way different environment, it makes me feel uneasy about what I'm getting when I know I had to fudge something up front, even if it matched on that day.

 

[Broz]

Phorwath, Your point is more than valid and the more I work with this, the more I understand your method. I have a gun club meeting tomorrow night. I hope to locate an Oehler to shoot through. If I do, and when this all irons out, I will buy one. You are convincing me on the oehler. Why? Just like Eaglet and others on the LB3.0, you are well educated with it. Kinda like I feel I am with the Lieca Swaro thing. Once again yesterday on the target at 1342 in mid day neither would get the target till I attached my Licence plate off my truck to the target. Then they both did and were in agreement. The Leica just did it easier and faster.. You bought one yet?

Thanks!
Jeff

 

[Broz]

Right now these number look good to me.

MV=2770
G7 BC=.410
DC= .495

I will see what Eaglet comes up with.

Jeff

 

[Broz]

I was wondering about the accuracy of our predicted trajectory when we tweek numbers and then move to a way different environment, it makes me feel uneasy about what I'm getting when I know I had to fudge something up front, even if it matched on that day.

Not to beat a dead horse, but this is what I do, or have done in the past. Day efore the hunt in the new envirment I fire 3 at 700 to 800 yards using my pda program for ups. At 7 to 800 the group should be fairly small and provide an easy and accurate center of group. Then a simple Tradgectory validation with exbal and I am on. I hear what you are all saying about "changing mv is a bad practise. But I still need convincing. That will come when the new program earns my trust.

Jeff

 

[bigngreen]

I think there is a lot to getting to trust your Ballistics program, having to work through Station vs. Corrected Baro is a prime one. I have had a lot of problems that were caused by a low end wind meter, I was at first ticked with Loadbase but then I figured out the meter was consistently reading low and it cost me a couple long range kills. Having a good crony,at least for me is like having a Kestrel.

I'm running the top of the line ballistics program but using sub standard equipment to gather the data, the saying "junk in,junk out" comes to mind. Not to mention this is always in the back of my mind when I'm lining up a long range shot and I know it affects how I shoot by making me second guess the data and then I make a last second change in my hold.

But until I can get it all bought I have to shoot a lot of shots to validate my data.

 

[Eaglet]

Right now these number look good to me.

MV=2770
G7 BC=.410
DC= .495

I will see what Eaglet comes up with.

Jeff

I'm late... spent time with the mechanic working on my Trooper and took the wife to dinner and before that bought some parts for my vehicle...

Broz, you're playing the game!!! That's alright!

In the results below you're giving a little more preference to higher velocity and I'm sticking a little longer with the BC...
I guess either one can be used.
I'm being... Interpolating a bit for the last two... you know between the 5's

Just a gut feeling, I think the bullets you have are more like the previous BC7 we used.

Phorwath's rant is very valid. Now, when it comes to buying a Chronograph let me tell you what Bryan Litz said about that in his book:
I'll be quoting him here.

After a couple of years of hauling the Oehler around with its 8 foot rail, I began considering other options. The CD Millenium Chronographs were becoming popular, and Oehler wasn't making chronographs anymore. So I bought a CED, but before using it for serious testing work, I compared it to the 8 foot Oehler first...

And then down lower...

The velocities measured by both units agreed within 8 fps. After repeating tha test several times, I was confidentthat the CED was capable of the same accuracy and precision as the big Oehler...

If you find an Oehler you'll be paying a whole lot more and for what?... now the M2 is out which is way superior, more sensitive than the former one and for less than $200.00 bucks. Why going back in technology when you can go forward. That's why I got me a CED M2...

Len Backus has written some place also, something similar about the CED and the Oehler. Well... let's just say he's using a CED chronograph.

Just go with your guts feelings though!!!!!!!

 

[Eaglet]

Ladies and Gents:​

Correction:​

In one of the former posts I made a wrong statement. I need to correct it!​

When you use a DC (Drag Coefficient) greater than 10, it places a lot of doubt on the bullet's BC; as you can see we're looking good there.​

CORRECTION: "The greater than 10 above is wrong" it should say: a DC change Greater than ±10% of 0.500

 

[Pdvdh]

Ladies and Gents:​

Correction:​

In one of the former posts I made a wrong statement. I need to correct it!​

When you use a DC (Drag Coefficient) greater than 10, it places a lot of doubt on the bullet's BC; as you can see we're looking good there.​

CORRECTION: "The greater than 10 above is wrong" it should say: a DC change Greater than ±10% of 0.500

Wondered what you were trying to state there Eaglet. I figured you'd straighten it out so I was patient. And sure enough you came through.

 

[Eaglet]

Wondered what you were trying to state there Eaglet. I figured you'd straighten it out so I was patient. And sure enough you came through.

Friend, I hope I got it right this time... When I wake up I'll check on it again!