Interesting ladder test results. Ideas?

[Mike Matteson]

At 79.6 you started to notice a slight increase in bolt lift or bolt lift became difficult? What powder?

He stating H1000.

 

[RUFFIAN R - NY]

what about your scale / powder and all the same lot brass -primers ????

 

[Nevrsummr]

Ladders are useless at 100 yards shoot them at atleast 500 and you will use less components to find your load.

Can you please explain this in more detail? With the first ladder i was looking mainly at velocity, not the target. With the groups i was looking for both low ES and tight grouping. At 500 yds it sounds like you would only be concerned with groups?

 

[Nevrsummr]

what about your scale / powder and all the same lot brass -primers ????

Rcbs chargemaster. I double weigh each charge and make sure it reads exact. That being said yes there is a tolerance factor there. I also leave the scale on for 24 hrs before using it. Same bottle of powder. Same box of primers. All prepped the same. The brass came out of 2 different nosler boxes. 25 rnd each box.

 

[Nevrsummr]

12fps at over 3300 is nothing.
Where did you get the load weights? Are you using auto balance/dispenser? I think the loads should be identical My Gen 6 weighs to my set target and shows me the weight actually dispensed which is usually identical for all rounds.
One thing that is a long shot is did you invert the powder can to make sure the powder is homogenous? I always do that so there is no clumping or the bottom of can has different amt of solvent than the top due to setting on the shelf. Just some ideas.
Another thought, if you do this again is do two identical loads for each step in the ladder.

Good idea, i will give my powder a mixing from now on. Rcbs chargemaster. More details in prev post

 

[ButterBean]

Just my 2 pennies, H1000 is too slow, lots of speed on the table yet and what neck interference are you running

 

[Nevrsummr]

Ejector ring/wipe is a sure sign of over-pressure, as long as it isn't a false positive.

Also, when brass is pushed like that toward the upper limit, the brass will give out, despite "functioning" correctly. This makes subsequent firings wildly non uniform. As the brass gives against the pressure, the velocity will drop, despite more powder. So, if you put in more powder, and velocity drops consistently, then you know for CERTAIN you are over pressure. That combined with ejector ring/wipe on brass is a certainty of being over pressure. Don't run there. Period.

Come down to the low node, and be happy and stable. Also, I do not subscribe to the velocity "flat spot" driven load development strategy. Not at all. How the shots print on target is the critical aspect. Velocity is not a factor other than a result.

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I didnt really see a lower node from my results but that is due to my method im sure. I guess my thought process is nosler brass shows ej marks early, and if it was 30 degrees cooler there probably wouldnt be any. I could be wrong though. I definitely agree with you on the brass life. I load sherman wildcats and i always start with a mild load to preserve brass life and fireform.

As far as the "flat spot" i needed to find out where pressure was anyways, and i do feel a flat spot is a good place to start looking. After that i look for low es and bugholes

 

[Nevrsummr]

Just my 2 pennies, H1000 is too slow, lots of speed on the table yet and what neck interference are you running

Hey butterbean! I was thinking h1000 was too fast. Lots of case capacity left but hitting pressure. If you are referring to neck interference as some people call neck tension, i run a mandrel thats .001 under. So .283 in this case. I havent tried using the FCD you made me on this rifle yet. Guess i probably should.

Two of my friends bought 28 noslers and i built a 28 sherman mag and i am doing load development on all 3 at the same time. Less range trips.

Hope you are well friend

 

[L.Sherm]

Can you please explain this in more detail? With the first ladder i was looking mainly at velocity, not the target. With the groups i was looking for both low ES and tight grouping. At 500 yds it sounds like you would only be concerned with groups?

Ladders have zero to do with velocity, your looking at vertical dispersion and a
" node". In a 28 I would do .4 spread on powder. Do 2 shots and look for almost grouping with those spreads and were it climbs again.
Most of the time theres a lower " node" and a higher one. I never do any kind of load development at 100 yards anymore. Not in my LR hunting rifles anyway.
Target tells you everything.

 

[Nevrsummr]

in short yes, generally you will see "higher" pressures or velocities in hot temps. For load dev in the heat of summer I would go back to the range in the fall or winter to check POI and grouping and velocities etc. and if anythings way off then fine tune another ladder test or seating depth.

Did you let the barrel adequately cool down before the different groups? Ive had odd velocity jumps in ladder tests when I was using only a cheap digital scale that went away when I bought an analog scale. Consistency in shoulder bumping, case trim, charge weight, seating depth, barrel temp are important. I also dont fully trust virgin brass until its at least fireformed once.

Barrel cool down every 2 shots. Did notice that hotter barrel = less velocity though. But that 3 shot group was consistently high.

 

[Nevrsummr]

Ladders have zero to do with velocity, your looking at vertical dispersion and a
" node". In a 28 I would do .4 spread on powder. Do 2 shots and look for almost grouping with those spreads and were it climbs again.
Most of the time theres a lower " node" and a higher one. I never do any kind of load development at 100 yards anymore.
Target tells you everything.

Thank you. This is an interesting method. I like it. Wish i had a place to shoot 500yd groups up here in the mountains of north id.

 

[L.Sherm]

You can either map your shots on target or color the top half of your bullets to keep track. They all should be shot at the same spot.

 

[Nevrsummr]

I learned this lesson the hard way when I switched brass in my 7RM. My #'s were all over the board with the new Peterson brass compared to my already developed load with RP brass. Once I retested with the fired brass low and behold my #'s fell right back inline with single digit SD. The Peterson brass actually took 2 firings before it was fully fireformed and settled in.

Some people dont like my wildcats because they say i have to waste ammo/barrel life fireforming. I agree with you, and i think everybody fireforms. I will check with some once fired brass before i finish though. Thanks for the reminder.

 

[Nevrsummr]

Now that your are that close, test different primers. I was very surprised how much it matters in my own testing…..

I could try cci250's but in my experience they usually boost pressure.