Any Tips for a New Loadbase User?

[Broz]

Just to keep the numbers fresh. At the beginning you had a Station pressure of 25.63 Broz, in the last post you had it changed to 25.3.

So. could you confirm the most accurate data for the day that is a known, this is what I come up with.

300 gr Berger bullet with a G7 BC of .455 and using .500 for a drag.

Clicks are at .250 with a sight height of 2.1.

Sight in is at 300yrds and is .5 in high.

Environmental is a Station pressure of 25.63, a temp of 70* and a Humidity of 30%.

The unknown is the Muzzle velocity.



So I re did my Loadbase tract to these numbers and used a MV of 2750 and I get 20.1MOA for a come up. If I go to a MV of 2740 I get 20.3 MOA. I would guess your MV somewhere in the 2750-2740 range. We will get to do this all over again when you get a chronograph and don't get 2750 fps

The data in these threads kinda gets out of wack and you have to update it to keep it accurate!!!!

Sorry, the 25.3 I typed was a Typo..My keyboard is fussy and you need to hit the keys firmly. The 6 didnt print. It indeed should have been 25.63 at sight in.

I believe you are correct with 2740 to 2750 MV I will chrono as soon as I get the new one.

So you are correct except for the temp at sight in. It was 75 at sight in and later when I shot to 1000 it had cooled a bit to 68. All other FC was the same or very close for the 1000 yard group as they were for sight in.

Thanks ! I hope I didnt make any more typo's , or mistakes as I appreciate everyones help here. All of this discussion has been great! I have learned a ton about this program and I appreciate it alot!

Jeff gun)gun)

 

[Broz]

Phorwath, Its all good! and I think I have it now. Granted, I will have more questions as I use this more but for now I'm confident. Doing this back and forth in a few different manners has helped me immensely in familiarizing myself with the functions.

Thanks to all!!

Jeff gun)gun)

 

[Broz]

OK, my 338 Lapua /300 Berger track is updated with the changes. I even entered the stability factor for this bullet in my rifle in the data/drift tab.

Now my dope for the 1000 yard group is 20.2 moa and checking the spin drift gives me .7 moa. That I would say would get me "Ground Squirrel" close at 1000 yards...

Thanks!

Jeff gun)gun)

 

[bigngreen]

OK, Broz I'll edit the post to reflect the info. These kind of things can get really twisted by the end of a thread, as the thread continues there is always more info.

I notice that your change of temp from 75 to 68 made a 1/10 MOA change during your time shooting, I think in MT you have to watch that you don't take a 10 or 20 degree change into account, some of us don't have a gun that will hold to that kind of accuracy but yours is.
I put a MV of 2745 and a 75* temp in and saved track then I turned on the field tab and just change the temp to 68* and the results were right where we are trying to be.

My corrections come out best at 2745 fps, I believe Loadbase can give you a close MV by doing it this way. But, the program is designed to have accurate sight in numbers and give you a spot on correction with no tweeking. I have gotten to the point that if my correction is not on target and my data is good I find what is wrong with my gun or my shooting position!!!

I found that I was not getting good corrections with Sierra bullets till I corrected to ICAO standard, I have been using a G7 BC of .381 for the 300gr Seirra with excellent results.

Phowath's work with Loadbase has inspired a lot of this confidence in Loadbase for me.

Glad you managed to get something from all our mess , you going to love Loadbase when you start getting into it!!!

 

[Autorotate]

I differ on the position that field drops are an equivalent, or better method, to establish MV than the chronograph. If you're doing everything else correctly with LoadBase 3.0, then an accurate MV input is the key to accurate long range dope predictions. I know some advocate relying on field drop data to infer a BC or MV. It's true that if one develops a good drop chart at a known set of environmental conditions, that that drop chart can be good-to-go under those environmental conditions, without any chronograph, known MV, or even known atmospheric conditions. Because atmospheric density generally doesn't change so greatly from day to day to cause a miss if one remains at the same elevation. However, having and entering good, accurate data into an accurate ballistics program will allow for accurate predicted dope under any future atmospheric conditions, angled shots, differing elevations, tropical depressions, or high or low pressure systems, and account for spin drift and coriolis affects as well.

I agree with what you wrote here 100%. You are absolutely correct that a gnats *** accurate MV (corrected for the effects of temperature and bore condition will have on MV or at least validate your system is "temperature tolerant") is key to LB being able to spit out ballistic data when the enviornment/range change.

My previous statement was in the interest of getting Broz mystery solved, as his zero and extended range conditions are in the same location (and hopefully environmental data), that he could quickly derive what his velocity should be using drop data. Then once he get's his chrono in a week or two, he should know what to be looking for within 25 fps.

 

[bigngreen]

OK, my 338 Lapua /300 Berger track is updated with the changes. I even entered the stability factor for this bullet in my rifle in the data/drift tab.

Now my dope for the 1000 yard group is 20.2 moa and checking the spin drift gives me .7 moa. That I would say would get me "Ground Squirrel" close at 1000 yards...

Thanks!

Jeff gun)gun)

Right on!!! Make sure to input your Coriolis it will make a difference!! Also check out how the multiple wind zones works, I shoot a lot of canyons and found that I use multiple winds more and more.

 

[Autorotate]

Notice that Barns, Hornady and Sierra have metro based BCs and when using LB3.0 you need to convert those BCs to ICAO by doing what it says on the third paragraph.

Thank you Eaglet for that important tidbit.

In a shameless plug for Bryan Litz's book, here's yet another reason why 40 bucks spent on his book is a better value than 1K F215GM primers

Bryan provided G7 derived BCs from his experimental testing that is already referenced to the ICAO standard atmosphere for a large library of nearly every popular bullet in his book, ready to plug into LB Data > Sight-In page, without concern to whether you did the conversion correctly, or if the factory "juiced" the numbers for marketing purposes.

 

[Pdvdh]

I can't believe I was so late to the dance. Well, looks like all is good now!

Just some extracts that are good to keep in mind. Notice that Barns, Hornady and Sierra have metro based BCs and when using LB3.0 you need to convert those BCs to ICAO by doing what it says on the third paragraph.

Great photo-post Eaglet. I consider you to be our in-house (resident) LoadBase guy, with the knack for Posting the good visuals! I was waiting for you to jump in yesterday. See what happens when you take a day off from prowling the LRH Forum!

 

[Broz]

It was totally beautiful this evening. Not a hint of wind at the gun or target. It is not often I see the streamers hanging straight down at my targets in the hills. So I decided to take a few shots at 1000 and at my 1395 yard target using loadbase.

Let me first say that I am still very impressed with the 300 gr 338 Bergers. They are consistant and tight. I still feel that I can improve my load with tweeking the seating depth and maybe the charge too. Plus I havent tried the Fed GM215M primers yet. So for just a quick load I put together these bullets are doing the job!! Thanks to the folks at Berger Bullets.

OK, Loadbase results. I did the dope for 1000 and to my surprise I was left and low about a foot. So I dialed it in.

Using that windage for a start I did the dope for 1395 yards and added .25 moa more left for spin drift to the windage that was on at 1000. Load base gave me a come up of 36 moa. Here is the target after I fired only 3 shots at it.

So the ups were right for 1395 but not for 1000. The spin drift was off or maybe the corialis will fix it as I am not using it yet.

The plan now is to get the chrono, fine tune the load, check the scope tracking values, and keep dialing in till the first round cold bore shots are spot on.

See, my .338 Lapua is not quite a 1/2 moa rifle all the time..

jeff gun)gun)

 

[bigngreen]

That may not quite be quite 1/2 MOA but it is 1/4 MOE if ya know what I mean .

Once you get used to the program and running it then the fun starts!! I'm liking the looks of the 338 LM and the 300 Berger combo. What twist rate is you barrel?

 

[Broz]

What twist rate is you barrel?

1 in 10

Jeff

 

[japple]

That is some seriously good shooting! Keep it up!

 

[Pdvdh]

So the ups were right for 1395 but not for 1000. The spin drift was off or maybe the coriolis will fix it as I am not using it yet.

The plan now is to get the chrono, fine tune the load, check the scope tracking values, and keep dialing in till the first round cold bore shots are spot on.

See, my .338 Lapua is not quite a 1/2 moa rifle all the time..

jeff gun)gun)]

Hey, I'd take that 3-shot group at that distance any day of the week. I'd still trade my chrono's!

Coriolis & spin drift will play a significant role at 1400 yds. Even at 1000 yds. Spin drift rate increases at increasing distance. I can't remember well enough to explain why, but it does. I get a little more coriolis at 61 degree North Latitude than you will down there. But do incorporate the spin drift and coriolis dope for - I'd say - 800 yds on out. Especially anything from 1000 yds on out.

Pretty sure that if you get all your stuff confirmed and entered properly, LB3 will put you on the mark. Yes - check your turret values and ensure that the real-life correct value is entered correctly in LB3. Nightforce is supposed to have their act together, but you never know until you field check your turret/click values.

Since you've been an Exbal user for quite some time, be sure to let us know how the two measure up after you get more familiar with LB3. I've got a hunch you're gonna be one of our LB3 experts in short order. I'll be the one asking you questions. Seems like you shoot more than most.

I went with LB largely based on the Threads and Posts Eaglet provided over the years. He's used a number of different ballistics software programs and boasted about LB to the point I couldn't stand it any longer - had to buy it. And no regrets from me. The customer support is the best. This thread is just one example of "Gus to the Rescue".

 

[Broz]

So, I really need to take a good look at several things. But lets just for conversation sake say that the dial ups loadbase gives me for 1000 are 1/2 moa low but are on at 1395. What can one do, if anything with loadbase to correct this? Fudge the BC??

Jeff