ladder test results

[Catfish26]

Let me start by saying I think I have a pretty good load, just may be too finicky. Lapua brass, federal gold match primers, 41.5 H4350 with 140 SMK's that measure 2.200 to the Ogive. This load is for my DPMS 260, stock 24 bull barrel, 8x32 nikon monarch scope, Geissele national match trigger. I am getting 2600-2650 out of this set up. I full length size, seat with a redding comp die, check run out on loaded bulletets they are good, powder is thrown from an RCBS beam scale, I trickle and count every grain to be exact as I can be on the load, on 5 shots I see SD at 21 Es at 7. I have tested through a led sled and also off a Harris bipod with spikes and a rear mono pod. At 400 this has produced groups around 2.5 to 3.0; this is inches, not MOA. My issue is the **** flyers, several times I have shot groups that are 4 inches or so, if you minus the one flyer, 2.0-1-3/4, and 4 out of 5 look great. The flyer will be just about anywhere and come from any shot, I do not believe it's me, that why I tried the led sled. I also have similar results from 43 grains of H4350, RP brass, 123 scenar, at 2750 fps, so that's why I developed the 140 gr load. So after reading tons of articles on ladder testing and OCW, thought maybe my load is just on the edge and needed to refine it. For today's test it was a little windy, winds were 10-15 mph out of the south, which creates a right to left wind for me, so I was only concerned with the horizontal strings. So it would seem that shots 1, 2, 3 for sure, maybe throw in 4 but figured I would go back and try 40.3, and maybe play with seating depth if needed, pretty slow but had a great horizontal spread and looked good. But if you measure shots 5, 6, 7, 8, 9 its 3.631, not too bad, Thoughts? Thanks in advance for your help and suggestions. Chrono didn't capture 2 shots.

40.0-2509 fps
40.3 na
40.6 na
40.9-2604
41.2-2599
41.5-2624, Not that used it for the 2 sighter's and 2599, 2604. Today was 45 degrees.
41.8-2640
42.1-2650
42.7-2704 no pressure signs yet.

 

[FearNoWind]

... on 5 shots I see SD at 21 Es at 7....

IMO, you can't get much useful data out of 5 shot groups. For MV data I typically suggest a minimum of ten rounds
With an ES of 7 I don't see how you could have an SD of 21.

Take out the wind and 1,2,3,4 look pretty good. I assume that "N/A" means no chrono data. Still, that's the region I'd stick with for the load you're testing.

 

[Catfish26]

Correct for on the NA Chrono didnt capture it for some reason. Thanks for the info. I usually shoot 5, 4 or 5 shot groups, but i have always just checked the 5 shots for ES and SD. I will run a longer string and see what I get. I just checked a few more notes and I have 21 and 7 and 16 and 8 for ES and SD. Are those just way to high, or did i get the SD and ES reversed? What would be good ES and SD for a 20 shot string?

 

[FearNoWind]

... Are those just way to high, or did i get the SD and ES reversed? What would be good ES and SD for a 20 shot string?

I don't usually worry too much about SD, but ES gets my attention when a load isn't working quite right. I've found that if I focus on ES, the SD falls into place quite nicely. I also don't work on the load from a SD/ES perspective. At the start of load development I'm interested exclusively in how it prints on target. If I can print 10 rounds in .5 MOA I'm happy as a pig in clover. Then, and only then, do I consider SD/ES. I would hope to keep ES under 25 .... and with groups at <.5 moa I'm confident that my ES is pretty darn stable. If I'm curious about SD, at the ES level of 25fps it's typically around 8 - 10.
But that's just my style. It shouldn't be considered superior to the way others approach load development.

 

[Catfish26]

Thanks for the input, I will check some 10 shot groups and see what I get. Will also run on it on a few other loads out of curiosity.

 

[Catfish26]

Got back to some testing today, very happy. Turned out 40.3 at 2.210 seems to be the ticket. Will need to do a little more testing to confirm. These were shot at 225 yards today.

 

[Catfish26]

FearNoWind, I did have them reversed as notes were not in front of me at the time of the post, thank you for pointing that out I should have paid more attention. During yesterdays test, I did do a 10 string and ES was 20 and SD was 8. For what its worth more times that not my best groups don't seem to have the lowest ES and SD....now that could just be blind luck? In each 5 shot groups I have one that got away. Since the shot felt good at the break, I couldn't call it a flyer. The high left shot was the first shot, barrel was warmed up but not hot. Don't recall the other group. Do you or would you consider either of the shots in the photos a flyer or just part of the group?