What am I doing wrong? Explanations/Tips 300WSM Berger 200.20X

[64E]

Loading a 300 WSM with Berger 200.20X, 62.0 H4350, CCI 250, Norma brass, 3.266 CBTO. Disclaimer: This load is only safe in my rifle, do your own load development please. Manners EH1TK, Proof Carbon Prefit, Area 419 20 MOA rail, factory Tikka Action, Bushnell LRTSi. The Berger box G7 is .328. Selected the G7 from both Kestrel library and StrelokPro library, both list it as .328 which matches the box value.

Cold clean barrel had 170 rounds on it at the start of the day. After three rounds in the picture, settled on averaging 2900 fps as expected on the Labradar.

300 yard group dead on elevation.

Went to 600 for the first time. Dialed 3.4 to get hits and they were all low on target. Verified range as 599 with Leica range finder. Actual come up looks to be 3.6. Both ballistic instruments give me just over 3.2 for a solution. If I use the truing function on the Kestrel it’s puts MV below 2800. Surely my Labradar isnt that far off. Any suggestion?

 

[DFOOSKING]

Had to delete my original comment after I re-read post 3 times.

My Shooter app has listed a Berger 200gr hybrid with a bc of .320....

I ran that at 2850fps and my average environmentals today (its super early as I type this) and got 3.3 for 600yds.

2825fps gives 3.4 for 600yds....

2800fps gives 3.6 for 600yds....

Maybe you have slight tracking error in your optic?

Or maybe you have to do what Frank G. often says here, "believe the bullet".

Wtf do you really care what the speed is as long as it's shooting well? I mean obviously you may require enough kinetic energy on target. But 2800fps isn't exactly crawling.

 

[64E]

Thanks. I reached the same initial conclusion as you. I think my next step is a tall target test to verify the scope.

I don’t care how fast it’s going, but 100 fps off seems unlikely to me. I’ll be going somewhere to hunt with an 8k elevation difference from where I’m load developing so I need confidence in my Kestrel.

Anyone else have a real world BC for the 200.20X? I can’t access beyond 600 for a few more weeks.

 

[Slides]

Bore axis to scope is correct?

Zero distance confirmed with the rangefinder too?

 

[Seymour Fish]

Bore axis to scope is correct?

Zero distance confirmed with the rangefinder too?

Good thoughts. Wonder about his setup and delivery. Bench/prone/bipod/ rear bag/death grip first time to 600,etc. needs to be identical to his short range zero setup

 

[64E]

Bore axis to scope is correct?

Zero distance confirmed with the rangefinder too?

Yes to both.

 

[64E]

Good thoughts. Wonder about his setup and delivery. Bench/prone/bipod/ rear bag/death grip first time to 600,etc. needs to be identical to his short range zero setup

Concrete bench. Atlas bipod, schmedium waxed canvas game changer with heavy fill for both distances. Same setup on all distances.

 

[diggler1833]

A lot of good advice, so I'll just share my experience. Assuming that your shooting position and surface is exactly the same, and acknowledging that you appear to be pretty familiar with everything that your doing:

I have had this a couple of times, but am usually only .1 - .2 off at 500-600 yards. I figure it is the error in my cheap chronograph, so I use it as a baseline at 100 when I do load development, and then verify my velocity at 500-600 with drop.

You have to make sure you measured your bore centerline to optic centerline correctly, and it wouldn't hurt to run a tall target test (although most "decent" optics are off .1 or less at 10 mils...but crap breaks).

I find that once I true my velocity to drop at 500-600, that the drop in my app hasn't changed at all at 250-300 (which is what I shoot from my house usually). For example: Saturday I took my second 6.5x47 to 603. My table based off the chronograph showed me a come up of 4.0. I fired a cold bore (way left...F/U that wind call), and then 5 more for a group. Looks like I need to come up .1, so I lower velocity by 10 FPS, and I'm at 4.1 up...but at 300 I'm still at the same 1.2 mils come up that I've shot this load at a dozen times.

It was the same for my other 6.5x47 a month or two ago, but my chronograph reading was apparently a bit slow. I only got to 492 that day because of the grass height in the pasture, but I was .1 high. After adjusting the velocity, my 300 drop data hadn't changed.

Guys who shoot a lot farther than me will often true their BC once they've trued their velocity. I don't do it because 98% of my shooting is at 750 or less.

At this point, I do kind of look suspiciously at your Labradar or how it is set up because of the outputs your software is giving you...but I've been wrong before. One way to tell is to input your new velocity for updated drop data at 600, and then see how far off you are at 300.

I'll be watching to see what you discover once you figure it out as it may help me down the road. Best of luck.

 

[6.5SH]

Upload a zip file from the LabRadar session here:

Geladen | Labrabaco

You need enough shots for it to be statistically valid but the tool can also give you an idea how good or bad the tracking was if you aren't familiar with reading the raw csv files.

 

[64E]

Upload a zip file from the LabRadar session here:

Geladen | Labrabaco

You need enough shots for it to be statistically valid but the tool can also give you an idea how good or bad the tracking was if you aren't familiar with reading the raw csv files.

That’s awesome man. Thanks

 

[64E]

Update: Tall target test 10MIL dialed at 100 yards resulted in 37 inch actual come up. Should have been 36. This is a hunting rig that I will limit to 600 and in anyway and I do not think this amount of error is enough to worry about. It did reveal my scope is out of plumb very slightly. Drifted 1 inch left over 10 mils.

This result has me flummoxed. The zero at 100 was slightly high as you can see in the picture. I would have expected that to translate at 600 into a slightly high group as well. Not requiring more elevation than my solution computed.

 

[6.5SH]

Update: Tall target test 10MIL dialed at 100 yards resulted in 37 inch actual come up. Should have been 36. This is a hunting rig that I will limit to 600 and in anyway and I do not think this amount of error is enough to worry about. It did reveal my scope is out of plumb very slightly. Drifted 1 inch left over 10 mils.

This result has me flummoxed. The zero at 100 was slightly high as you can see in the picture. I would have expected that to translate at 600 into a slightly high group as well. Not requiring more elevation than my solution computed.

I was going to ask if the picture of the orange dot was of your zero. Eyeball says it is ~0.15 mils high, but like you just mentioned if this is true even with added offset to either engine it will result in the 600 yard data being even higher not lower.

Something to ponder, I know your LRF is a quality brand but stuff does go bad or give an off reading due to environment etc. Try a $20 300 Ft open tape reel to confirm your zero target distance. If you found out you were zeroing at say 90 yards with that much vertical offset a whole lot starts to line up and make sense.