Getting Rid of the Vertical

[Hondo64d]

I'm thinking if I can tune the vertical out of this load, it will do everything I could possibly ask of it. I'm probably going to start with systematic seating depth adjustments. Is that the right approach for getting rid of vertical stringing?

Thanks,

John

 

[doc76251]

Re: Getting Rid of the Vertical

THAT vertical isn't because of your loads, that is breathing or mounting.

To the original topic, yes messing with seating depth will give you the fine tuning you are looking for.

Cheers,

Doc

 

[Hondo64d]

Re: Getting Rid of the Vertical

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: doc76251</div><div class="ubbcode-body">THAT vertical isn't because of your loads, that is breathing or mounting. </div></div>

Maybe, but it does not do this with H4831. I just thought the horizontal spread on this load was so good that if I could tune out the vertical, I would be done with load development.

Here's a group with H4831 for comparison.

John

 

[MALLARD]

Re: Getting Rid of the Vertical

testing at 100y has its flaws , its possible the vertical is related to a parralax issue. If you want to dial out vertical you should look into a harmonic tuner

 

[doc76251]

Re: Getting Rid of the Vertical

I would look into my position and refine my technique 1st if this is a good OCW load. A 1" POI change in a group would require a variation of ~3 gr of powder to have that much effect. Parallax would do that, breathing, cheek weld and butt placement would be the 1st things I would consider. Even your 2nd photo has a lot of vertical in it for what appears to be an outstanding load.

One other option you may wish to consider is NOT shooting where you are aiming. If your bullets impact the point of aim you will subconsciously "aim to the middle" and get vertical as a result.

Cheers,

Doc

 

[Ballistic308]

Re: Getting Rid of the Vertical

As said above, if this is an OCW then bullet seating depth should get rid of it. When you shoot different powders they will have different pressure curves, whip, and barrel time, so the results will differ.

Sometimes the rifle maynot be seated into your shoulder from shot to shot and this will cause vertical stringing, so verify it's firmly seating the same way everytime regardless of when you want to "make it count" or not.

Good luck.

BTW- breathing/heartbeat is seen left-to-right impacts.

 

[Jeepocabra]

Re: Getting Rid of the Vertical

Have you ladder tested this load? Culd be that you are out of the node.

 

[Hondo64d]

Re: Getting Rid of the Vertical

Haven't done any ladder test yet. Don't have easy access to shoot beyond 100 yards. Plan on doing it, but have to have the time for the 1.5 hour drive to 300 yard range.

John

 

[Ballistic308]

Re: Getting Rid of the Vertical

This is like a mini ladder....

There are other ways to determine whether or not you're in the right spot. You could load up one round of what ever you think your load is, then load one round .3g lower and then another .3g higher...maybe even a couple of each as mistakes can be made like pulling a shot, etc. When fired note exactly what round makes the hole in the target and examine for the round that is out of the group.

For example if you load 40.0, 40.3, 40.6 and when fired the 40.3 and 40.6 load group together, the POI (Point Of Impact) is suggesting to move higher in charge weight as the low charge is not wanting to group with the others. So load up 40.3, 40.6, and 40.9 and fire them, 9 times out of 10 this will certainly proof the load when there is some uncertainty or when you are very close to a good load.

This method can also be used when changing to a different lot of powder.

I have to ask, did you happen to remove the action from the stock prior to shooting the group in the original post?

 

[bohem]

Re: Getting Rid of the Vertical

Generally for that kind of horizontal spread (super tight) but 1MOA of vertical I look to shooting position a little and then address the powder charge.

Add 0.2-0.4gr of H4350 to that load and I suspect highly that the vertical will tighten up a lot.

 

[Grump]

Re: Getting Rid of the Vertical

Yeah, all this talk of potential positional problems is all fine and good but ignores the OP's information.


ONE group with a different powder doesn't do it.

ASSuming that neither posted group is a fluke (that's why the NRA does 5, 5-round groups), then yes, look to load development.

First, clues may be in velocity spread. The slowest might not be the lowest impact, especially at 100, but DATA is your friend.

Second, clues could be in light/atmospherics. Mirage can move the image of your target that far (1 inch at 100) if it's there for some shots but not for others. Conditions can change quickly, and even heat from the barrel can mess things up.

Third, seating depth is something to try. I have no idea what to expect other than lower velocity loaded longer. I'm not the guy to ask and I wish someone who's fiddled with this a lot will chime in. The one time I saw it done it was a Rem700 with a quarter-inch of freebore and it didn't make much difference in vertical OR horizontal dispersion.

Fourth, primers sometimes make a difference. That's part of load development! Or at least fine-tuning. My favorite load seems to shoot better with regular CCI 200s than BR-2s. Yeah. Not ready to re-test WLRs, but I have about 3,000 of them...

Fifth, shooter fatigue and possible positional elements still need to be considered, especially if this is a one-group sample of each. From a stats standpoint, I like 15 total shots for accuracy testing. Groups are smaller with 3shots than with 5, so don't compare apples to oranges. But get a reliable sample.

Sixth, I refuse to speculate on the efficacy of sacrificing a spoonful of powder as a burnt offering to the Accuracy Gods, since I'm a Christian-type guy who avoids that stuff.

 

[Hondo64d]

Re: Getting Rid of the Vertical

Here's a little more to ponder on. Shot this load right before the one posted above. Powder charge doesn't seem to make much difference. Same vertical dispersion...

Here's another of the H4831 Load. While not as good as the first, I don't see the extreme vertical that I experienced with H4350.

John

 

[excaliber]

Re: Getting Rid of the Vertical

Most of the time you can get rid of verticle stringing by going up in powder charge. If you can`t go up because of pressure, change powder. What causes verticle stringing is the harmonics of the barrel with the pressure curve of the powder you are using. Just because one load from somebody else`s gun work`s for them doesn`t mean it will work for you. Who ever tells you that a certain powder won`t cause stringing is proof that they haven`t shot alot with different loads in different barrels . Good luck

 

[Cigarcop]

Re: Getting Rid of the Vertical

I would powder up a bit until it goes away and it will at some point.

 

[Boomholzer]

Re: Getting Rid of the Vertical

Reading through; Try to limit the variables. CCI BR2 is a good primer, I'd trust that. Good platform powders but no step condition in charge. You have top-o-line, assumed re-necked brass in unknown condition (virgin?). I also assume Berger in VLDs? more work to fine-tune. From what I gather it's not a simple recipe. There is also no expectation in performance across other loadings, even factory, or stated rifle/chamber.

If the brass is new, I would'nt worry about it now. If the rifle's throat is long, I would not focus on bullet seating as something to intially change although i would consider not compromising bullet seat in this condition as it is a ill with longer jump.

 

[fmelloni82]

Re: Getting Rid of the Vertical

If your using a long grain powder out of a thrower i can almost guarantee that's the problem, My rcbs measure cant meter varget the best I get is +/- .5 grains. If you haven't tried it already try weighing 5 charges and see what you get. With as perfect as your horizontal is Its hard to blame your trigger finger for ALL of it. And all the tweeks help too, pocket uniform , debur ect. Whats happening is somewhere along the line your getting velocity inconsistency. See if you can et hold of a chrono to confirm this. If your muzzle velocity is that far spread then you know its the load

 

[Dionis]

Re: Getting Rid of the Vertical

Any chrono data from the vertical string? Do you cook round in the chamber?

 

[Burleyboy]

Re: Getting Rid of the Vertical

I run 45g h4350 with 130's in my 260. It's a hot load but that's where it really came together. Sometimes higher pressure loads run more consistent.

Bb