Scatterlee [sic] Load Dev for .270 Win

[barlowrs]

Hi Everyone. I am hoping you can help. I have never used the scatterlee method before, so I decided to give it a try. I shot 3 shot groups of 0.2gr increments for a new bullet I am trying out. What nodes would you hone in on here and what would your next step be? Would you try to do a few rounds at 0.1 gr increments in those ranges, or move onto seating depth for groups now?

Charge Weight	Avg Vel (ft/s)	SD (ft/s)	ES (ft/s)	Min (ft/s)	Max (ft/s)	Comments
54.00	2964.0	11.5	22.0	2955.0	2977.0
54.20	2985.0	10.6	20.0	2973.0	2933.0
54.40	2988.0	8.5	12.0	2982.0	2994.0
54.60	2963.3	8.0	16.0	2955.0	2971.0
54.80	2964.7	5.0	10.0	2945.0	2955.0
55.00	2988.0	20.3	39.0	2972.0	3011.0
55.20	2994.7	9.6	19.0	2986.0	3005.0
55.40	3027.0	16.6	31.0	3015.0	3046.0
55.60	3026.3	14.0	27.0	3015.0	3042.0
55.80	3036.7	4.7	9.0	3033.0	3042.0	Day 1
55.80	3044.0	5.5	10.0	3041.0	3051.0	Day 2
56.00	3052.7	8.1	16.0	3044.0	3060.0	Tight Group
56.20	3075.0	6.7	12.0	3068.0	3080.0
56.40	3082.3	5.7	11.0	3076.0	3087.0
56.60	3115.0	4.6	9.0	3110.0	3119.0	Tight Group

Forum Boss: The method is called Satterlee. See:

 

[FeMan]

You will find few folks on here subscribe to the Scatterlee method. I would chase the ones that grouped the best and not chase velocities "nodes" and ES/SD and tune with the target rather than the chronograph. There are a lot of things that matter, but in my experience seating depth has more effect on grouping than speed and the other factors.

 

[TTE]

What are the details of your firearm/cartridge ?
Do you know where your max pressure or load is ?

 

[barlowrs]

What are the details of your firearm/cartridge ?
Do you know where your max pressure or load is ?

All details are in the gordon tool picture, but summary:

Gun: 270 tikka T3x ultralight
Brass: Federal once fired, full length sized with .002" shoulder bump, trimmed to 2.53", flash hole deburred. Avg Case volume of 68.86 gr water
Bullet: 130 gr Barnes TTSX
Primer: CCI No 200 Large Rifle
Powder: Ramshot Hunter (Charges in the plots and screenshot) suggested book range is from 51.0 to 56.6 gr
COAL: 3.30"

Max pressure: Per the book 56.6 gr is max and as High as I went in this test, but there were no pressure signs at this point. Per my calibrated gordon reloading tool, it estimates I could go up to 57.4 gr before I exceed gas pressure and risk blowing things up. SO based on book, this and my actual fired cartridge's, I am still very safe.

 

[barlowrs]

You will find few folks on here subscribe to the Scatterlee method. I would chase the ones that grouped the best and not chase velocities "nodes" and ES/SD and tune with the target rather than the chronograph. There are a lot of things that matter, but in my experience seating depth has more effect on grouping than speed and the other factors.

This is what I have always done on my past rifles and reloads, but I was using pretty well known combinations so it was easy to find something that grouped well. This is a pretty new combination, so I figure I should start with velocity nodes to dial in charge, then tune seating depth for groups.

 

[Webster]

Hi Everyone. I am hoping you can help. I have never used the scatterlee method before, so I decided to give it a try. I shot 3 shot groups of 0.2gr increments for a new bullet I am trying out. What nodes would you hone in on here and what would your next step be? Would you try to do a few rounds at 0.1 gr increments in those ranges, or move onto seating depth for groups now?

Charge Weight	Avg Vel (ft/s)	SD (ft/s)	ES (ft/s)	Min (ft/s)	Max (ft/s)	Comments
54.00	2964.0	11.5	22.0	2955.0	2977.0
54.20	2985.0	10.6	20.0	2973.0	2933.0
54.40	2988.0	8.5	12.0	2982.0	2994.0
54.60	2963.3	8.0	16.0	2955.0	2971.0
54.80	2964.7	5.0	10.0	2945.0	2955.0
55.00	2988.0	20.3	39.0	2972.0	3011.0
55.20	2994.7	9.6	19.0	2986.0	3005.0
55.40	3027.0	16.6	31.0	3015.0	3046.0
55.60	3026.3	14.0	27.0	3015.0	3042.0
55.80	3036.7	4.7	9.0	3033.0	3042.0	Day 1
55.80	3044.0	5.5	10.0	3041.0	3051.0	Day 2
56.00	3052.7	8.1	16.0	3044.0	3060.0	Tight Group
56.20	3075.0	6.7	12.0	3068.0	3080.0
56.40	3082.3	5.7	11.0	3076.0	3087.0
56.60	3115.0	4.6	9.0	3110.0	3119.0	Tight Group

It's a hunting rifle not a competition rifle. You will get lost in the numbers. I need to look up what the
Saterlee Method is. Sounds like something created 50 years ago by a non-competitive shooter. I only look at group size. I don't care what the numbers are. I would look for a load that produces a small round group with a small group each side of it. Shoot your load with the best group 3 5 shot groups and see how they differ, this will tell you a lot about what your capabilities are and how good the rifle can shoot. I would think a group that is round and close to 1 inch is fine for a hunting rifle unless you want to shoot over 400 yards. I always tell guys when your hunting how big of a group do you shoot standing when you have been walking for an hour. Accuracy when a deer is walking at 100 yards?

Just looked up the Saterlee Method. There is a demo on YOUTUBE.COM. The guy on the video seems sincere but I think he should know 1 shot ignores any real variability that is occurring. I think any competitive shooter would laugh at it. He is looking for a flat spot in velocity shooting 1 shot at each powder charge. There is no such thing as a flat spot. It only exist because your plotting a small number of shoots at each load and ignoring that an ES exist. If you shot 10 shots at each load and plot all of them on a chart the flat spots come close to disappearing. The ES and SD get much worse. Speedy Gonzales destroyed the competition at 3 short range (100-200 yds.) National events in 1 year with an ES of 70.

 

[wkdickinson]

I personally don't think ladder testing is valid at all, in fact I think it can be misleading. But if you do and you need a way to analyze you results, this is a great tool:

ChronoPlotter

ChronoPlotter Easily create clean, customizable charts and graphs of your load development sessions with little to no manual data entry. ChronoPlotter is free and open source, works on Windows and MacOS, and supports most chronographs and e-targets. Download Quick Start Guide Read our research...

chronoplotter.com

 

[jelenko]

If you're using GRT and have calibrated it to a load in your rifle, you could try one of the accuracy nodes that the OBT function predicts. I've found accuracy nodes within +/- 2% of the recommendation - often right at the recommendation.

 

[Forum Boss]

We have tested a few Tikka T3s. Good rifle, but it's a hunting gun. Most would not deliver much better than 0.8 MOA accuracy and that's for 3 shots.

First, the Tikka website is not showing a current T3X "ultralight". Perhaps you mean the T3X "Superlite".
See: https://www.tikka.fi/en-us/rifles

I think chasing nodes via SATERLEE method (not "Scatterlee") is worse than a waste of time. As that production ultralight contour barrel heats, the POI can shift and accuracy can change. Your continued shooting won't prove anything.

Additionally, your Federal brass will likely loose accuracy potential after 3 firings (and maybe after 2).

I would take those Barnes TTSX bullets, seat them .030 or .040 off the lands. Work up a load on a warm day to find the very initial signs of pressure, then back off 0.5 to 1 grains.

Confirm with three shots with a cool barrel that has been fouled -- what you'll be shooting on that hunt.

Hate to say it, but it's just not worth the time, barrel life, or component cost to do extensive node testing with that gun.

Sportsman's Warehouse is showing Tikka T3X Superlilte with a fluted barrel. All the more reason you can't expect a high level of accuracy and will find that POI wanders as the barrel warms.

So, if you get 1 MOA for three shots, with a load that is safe on a very hot day, be satisfied. Go to the field and get your deer, then clean the barrel and put your Tikka back in the safe.

T3x SUPERLITE

 

[Forum Boss]

Additionally, in a previous thread by barlowrs that I deleted, he posted evidence that he had excessive loads, because of obvious flattened CCI primers and a couple blown Winchester primers. Some posters postulated that the blown primers (which damaged his bolt) may be defective, but there was clear evidence of excessive charge prior to that with the non-defective CCI primers. That suggests a measuring error or some other fault.

This is one of the flattened CCI primers. That's all you needed to see. Member barlowrs probably should never have exceeded that charge. It is complicated, as there are some other reasons for flattened primers, but it is usually an overcharge.



Again, this is a hunting rifle. It seems like, with the damage you have done already to your bolt, you might be better off with some quality factory ammunition.

 

[LVLAaron]

I'd land on 55.5 looking at your graph. - assuming it's safe.

 

[Dave M.]

Hi Everyone. I am hoping you can help. I have never used the scatterlee method before, so I decided to give it a try. I shot 3 shot groups of 0.2gr increments for a new bullet I am trying out. What nodes would you hone in on here and what would your next step be? Would you try to do a few rounds at 0.1 gr increments in those ranges, or move onto seating depth for groups now?

Charge Weight	Avg Vel (ft/s)	SD (ft/s)	ES (ft/s)	Min (ft/s)	Max (ft/s)	Comments
54.00	2964.0	11.5	22.0	2955.0	2977.0
54.20	2985.0	10.6	20.0	2973.0	2933.0
54.40	2988.0	8.5	12.0	2982.0	2994.0
54.60	2963.3	8.0	16.0	2955.0	2971.0
54.80	2964.7	5.0	10.0	2945.0	2955.0
55.00	2988.0	20.3	39.0	2972.0	3011.0
55.20	2994.7	9.6	19.0	2986.0	3005.0
55.40	3027.0	16.6	31.0	3015.0	3046.0
55.60	3026.3	14.0	27.0	3015.0	3042.0
55.80	3036.7	4.7	9.0	3033.0	3042.0	Day 1
55.80	3044.0	5.5	10.0	3041.0	3051.0	Day 2
56.00	3052.7	8.1	16.0	3044.0	3060.0	Tight Group
56.20	3075.0	6.7	12.0	3068.0	3080.0
56.40	3082.3	5.7	11.0	3076.0	3087.0
56.60	3115.0	4.6	9.0	3110.0	3119.0	Tight Group

Forum Boss: The method is called Satterlee. See:

I think a picture of the groups would be helpful in making the decision, as well as any useful info such as hard bolt lift, blown or flattened primers, or any obvious signs of over pressure.
Dave

 

[Adam in WI]

For a hunting rifle, using GRT... I've found their suggested charges in the OBT simulations to be more accurate than anything I've "stumbled on".

 

[Doom]

You will find few folks on here subscribe to the Scatterlee method. I would chase the ones that grouped the best and not chase velocities "nodes" and ES/SD and tune with the target rather than the chronograph. There are a lot of things that matter, but in my experience seating depth has more effect on grouping than speed and the other factors.

OP, Scott doesn't use this method now. The flat spots that exist are due to testing and sampling and are not real. There is a lengthy discussion of the subjectct on the thread below.

Load Development Using Chrono Velocity Ladder

Proponents of a single shot chrono ladder seem to have fallen out of favor due to the insufficient statistics, but wondering if anyone has tried this using a "valid" number of shots to find anything informative? Im trying to stay open minded.

forum.accurateshooter.com

 

[Webster]

OP, Scott doesn't use this method now. The flat spots that exist are due to testing and sampling and are not real. There is a lengthy discussion of the subjectct on the thread below.

Load Development Using Chrono Velocity Ladder

Proponents of a single shot chrono ladder seem to have fallen out of favor due to the insufficient statistics, but wondering if anyone has tried this using a "valid" number of shots to find anything informative? Im trying to stay open minded.

forum.accurateshooter.com

Keep in mind it's a 7.5 lb. Win 270 hunting rifle. No-one mentions Tony Boyers method. The OP has chosen the only bullet and powder he will use before he starts testing. It cost a lot of money and time to test 5 powders and 5 bullets. My varmint hunting rifle with a Krieger barrel shoots just about any bullet and powder under or close to 1/2". I found the 60 gr Sierra Varminter bullet clearly shoots better than any of at least 10 different bullets I have tried. This bullet shoots round groups around 1/4". Been shooting the same rifle since 1969. I keep buying new barrels.

Forum Boss: The OP is running a factory, ultra-light contour (probably fluted) barrel, with brass known to have poor longevity. There's a world of difference between a Krieger and that Tikka's factory barrel. Likewise a .270 Win is a far cry from a varmint cartridge.