Ran another ladder still can’t seem to find a clear path forward

[PowellSixO]

In my experience, horizontal grouping like the 8-1 through 8-4 group, have the best es and sd, and clean up with seating depth changes. Horizontal grouping is usually a result of seating depth, or shooter error. I would bet a bunch of primers, that group will clean up if you play with the seating depth.

 

[Sconnie42]

If you have time, give this a listen to. It can be found on Apple Podcasts as well. It aligns with finding neck tension, then seating depth, then charge weight and velo. I have yet to try it out as I just listened to it yesterday and it was fascinating to me

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modernzdaysniper.podbean.com

Very practical info and explains how the reloading world continues to evolve.

 

[StumpGrinder]

If I was going to shoot a match I would choose the lowest SD and do a seating depth test.
If it was a hunting rifle I would choose the highest node with SDs at 10 or below and do a seating depth test. I just did this with a 338LP and went from a 1.25 MOA group to a .25 MOA group with one seating depth change. I will remind you that some rifles just will not shoot some bullets or even some brands of bullets. I have a 6 CM that will not shoot the 103 ELD-Xs that I load but will shot factory ammo fine. However it will shoot Berger 105 Hybrids about anyway I load them.

I agree with sedancowboy, you can only do so much with powder charge. Then you move to seating depth adjustment and barrel harmonics. By the way I was born and raised in a town called Sedan, Kansas. Is that where your handle comes from?

 

[MAD10]

Randy,

If I missed what cartridge you are dealing with forgive me. It may help the forum if you listed what cartridge you are working on and components used - many will have safe starting places for you to try say nothing of the manuals or online sources from the powder manufacturers.

HOWEVER SAFETY FIRST....

obviously > what works for someone else maybe unsafe for your rifle. It is rare today that you'll be running a cartridge that someone on this forum cannot SAFELY help you get to a starting load and most if not all will caution you to start at least 10% lower than where they ended up. My point is you probably don't have to reinvent the wheel

That said what cartridge are you working on? Please include action, brass, powder, bullet, primer, barrel length and twist rate. This way if someone is familar they can advise you and or point you to a good source

 

[sedancowboy]

I agree with sedancowboy, you can only do so much with powder charge. Then you move to seating depth adjustment and barrel harmonics. By the way I was born and raised in a town called Sedan, Kansas. Is that where your handle comes from?

I am in Sedan Montana. A little place North of Bozeman, MT.

 

[david g ranes]

I agree with sedancowboy, you can only do so much with powder charge. Then you move to seating depth adjustment and barrel harmonics. By the way I was born and raised in a town called Sedan, Kansas. Is that where your handle comes from?

You say you grew up in sedan you old enough to have known Harry Kerr. David

 

[jebel]

Once you find a cluster or velocity flat, your development would then shift to seating depth test in that velocity/cluster node.
Then, start tweaking powder charges in that node in .2 increments, from low node speed to high node.

I agree with Bob's approach. In the test you're running, I only look at velocity - particularly the change in average velocity from group to group. I'm looking for a relative flat spot in group average velocity that spans hopefully several groups. You're making me do some work for you, because you didn't include average velocity or the change in average velocity in your picture.

Charge	Avg Vel	Change Avg Vel	SD Vel
70.5	2685		35.2
71	2708	23	15.2
71.5	2722	14	4.8
72	2752	29	21.8
72.5	2767	16	9.1
73	2786	19	11.8
73.5	2807	21	10.0
74	2823	16	24.6
74.5	2852	30	17.0
75	2863	11	10.7
75.5	2892	29	8.9

Assuming those numbers are right, I observe (1) I'm not seeing a super-outstanding flat spot, (2) best is 72.5-73 or possibly more broadly 72.5-74. I'd next move on to a seating depth test using a charge somewhere between 72.5-73.0. As others have mentioned, I'd use pretty gross steps initially, perhaps changing depth by 0.020 or 0.030 (not the 0.003 you mentioned). Be prepared to try long jumps, like 0.150. During that test, I would like to see groups tighten up and more importantly (for me) is to see a range of seating depth that are all pretty good. Refinement of both charge and seating depth can happen with smaller increments from there. You're looking for a spot within a range of charge and range of seating depth that are forgiving (less change from slight differences in either).

 

[coyotezapper]

It is a hunting rifle. This is also the second bullet I have tried first was 190 Berger and I couldn't seem to get it either. I have developed other loads for different rifles and either got lucky or something. Never had this much trouble. Do you have a recommendation for a seating depth test. My plan was to start at lands and work back .003 at a time

Start at .020" jump and go out in increments of .010" - .030" to .150"

Accuracy nodes at or close to jam are hard to repeat. Jump, jump, jump, the nodes are wide and repeatable

 

[skipglo]

Shot is wind less than 10 mph. From a bench with sand bags. Last group on bottom left was sighting a different rifle. But they are in order left to right, top to bottom. Starting lowest charge working to highest. 4 min between shots for barrel to cool. Started with a clean barrel

Personally I don't know what your markings on target refer to...but I'd be focusing on 6-1,2,3,4 or 8-1,2,3,4

 

[StumpGrinder]

OK, I'll try it. I'm going to get started on some load development for next year pretty soon. I assume that since I'm working with mag length as a hard stop that this method will work the same just start at mag length and go from there instead of lands.

Yes your mag length will be like jam, unless you want to single feed. For hunting that wouldn't be convenient. Also you may want to look into a harmonic balancer or barrel balancer they have different names. Basically it will allow you to tune the barrel harmonics to diffrent loads. Eric Cortina has a realy good one and videos on there use.

 

[StumpGrinder]

In my experience, horizontal grouping like the 8-1 through 8-4 group, have the best es and sd, and clean up with seating depth changes. Horizontal grouping is usually a result of seating depth, or shooter error. I would bet a bunch of primers, that group will clean up if you play with the seating depth.

Horizontal grouping is wind, a 150 grain 308 bullet moves about 2" at 100 yards in a full value 10 mph wind. I know you said the wind was less than 10 mph but unless you are in a wind tunnel they are not sustained at a given value. You may break one shot at 2mph and the next at 5 mph. Pressure has a direct effect on velocity. Neck tension, seating depth and powder charge variations will more likely give verticle stringing. If this is a hunting load 1 moa should be good enough for ethical ranges.

 

[StumpGrinder]

Do a seating depth run on the 8-1, 8-2, 8-3, and 8-4 load. That will clean right up.
View attachment 248932

I would hunt with this group all day long if it is repeatable.

 

[StumpGrinder]

Perhaps your rifle just doesn't like that bullet.

I didn't see what caliber the rifle is. Make sure the twist rate is adequate for that bullet. Bullets near the extreme of your barrels twist rate will start to show signs of instability but may not keyhole at 100 yds. Try them at 200 yds.

 

[Paladin300]

I would agree with the suggestion that you play with the seating depth. I had some issues getting the eld and eldx s to shoot in a 338. Called Hornsby! They need to be loaded at least 20 thou off the lands. Start there and work back. I would use the lowest SD which looks like group three if I am reading your data correctly. What twist is the barrel? Some 1/10 twist will not shoot the 220's. Also they just may not group well at 100 but will stabilize further out and may group at 200 and beyond as suggested above.