Ladder test, need advice for next step

[IllKeepMine]

I have performed an initial ladder test at 600 yds. .308 Win. Lapua case, Barnes 175 gr. bthp, fed210 and Varget. OAL is 2.810". Rifle is Rem. 700 mil spec 5R. I started with 3 rounds each from 42 gr. to 45 gr. powder. Grains varget vs vertical dispersion as follows.
This the sweet spot.
43.0 gr. 1.5"
43.5 gr. 1.8"
44.0 gr. 1.5"

I thought I would load 43 gr. to 44 gr in .2 gr increments for the next test.
What do you think?

 

[savageshooter86]

I would adjust seating depth now and shoot groups at distance. Shoot minimum of 5 shot groups. Find the seating depth test that shoots the best would be my vote. Looks like you have a good accuracy window

Donovan you got to pull out your fancy stuff don't ya. I really enjoy seeing how analytic your stuff is and your program You went with load # 9 right? I can't remember on this example

 

[Lapua40X]

While I agree that it is not technically a ladder test, (as dmoran pointed out) the data you have still has value and there is no reason why you shouldn't work with those 2 grain variables inside the two limits you listed, assuming that you're not hitting high pressure peaks. You may find a sweet spot in there. Keep in mind that the difference between 1.5" and 1.8" at 600 yards is more likely the shooter than the load. However, nothing ventured, nothing gained. If it feels good, go for it.
Hey, Donovan, I sure envy you having all that tech. stuff. IMO, it's the 8/9/10 string that gets the nod. Would that be correct? Would I be correct selection 64.2 as the working model?

 

[trailrider121]

Dmoran knows his stuff. He's program is fancy.

Illkeepmine, do you have photo you can share?

 

[LIUNA]

Very good example, that's why this site is the best, because we have the best.

 

[Nvreloader]

Dmoran,

Can you provide the name of that program you showed, and or a site to get more info on it.

VERY interesting!!!!!!!

Tia,
Don

 

[Nvreloader]

Dmoran,

Thank you, very OUTSTANDING work,

I can see that I am in the wrong crowd here, a shooter AND a puter program writer, ;D ,
I knew I was doing something wrong. :'(

I need to go back and start learning again, I am in over my head, I have a hard enough time just making this Boom Stick go Boom, and I am NOT going to learn how to write any programs, WAY OVER my head. ;D

Thank you,
Don

 

[jrm850]

Just for kicks Donovan, How does close does that great ladder node example come to an OBT node? Are you a believer in the pressure wave theories?

 

[IllKeepMine]

Wow, I just learned a ton. Thanks to all for your responses. I would have never guessed that my little request would yield so much information. Sorry that I don't have any photos. I gathered the data and disposed of the target. Will make a mental note next time around.

DMoran, Great program you have there. What language is it written in? Does it invoke some image analysis software?

 

[Rudedawg]

The game has changed so much in 30 years
I'm learning alot from you guys thanks for the info
And I haven't even asked a question yet
Rick

 

[jrm850]

jrm850 -

I did not have strain gauges/trace system hooked to that barrel. Nor did I compute the barrel time to check if it was on/off a OBT parameter.

Yes, I am a firm believer in Optimal Barrel Time and agree very strongly with Chris Long's theories. I use his OBT addition to the RSI software when ever I have my trace system/strain gauges in place.
Also, what I call OBV for "Optimal Barrel Velocity" that I believe coincides with OBT, and is where I feel there is "velocity zones" that barrels like, and will shoot about any bullet/powder combinations at those velocity zones accurately.

Good Luck......
Donovan Moran

I just switched primers from Wolfs to BR-4s and did a new ladder to see the changes. The nodes look classic and defined but they seem to fall directly in the middle of the calculated OBT and the barrel time numbers I'm getting from quickload. I'm wondering if I'm just not up to speed with quickload or my chronograph is out of whack.

28.0" Dasher, 105Hybrids, Varget 31.8 to 33.4 in .2 gr increments at 300 yds. 33.0 Looks happy to me but it is 30fps faster than the calculated 2950fps sweet spot.

 

[savageshooter86]

6,7,8 looks very good. Classic example of ladder test

 

[IllKeepMine]

After reading all of posts and doing some thinking (my brain hurts), I thought I would do another ladder test at 600 yds. Using Varget starting at 42.8 grs. to 44.2 grs. in .2 gr increments. I've tried .5 gr. increments from 42.0 to 45.0 and it looked like the sweet spot was 43.0, 43.5, 44.0 grs.

Does this sound a little over the top? What would you do?

 

[mr45man]

IllKeepMine
That's what i would do, its allways windy here so i just don't worry
about horizontal stringing when looking for the best vertical .
John H