Help with the results of my ladder test...


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Afy
December 28, 2008, 06:19 AM
Trying to get my loads better and groups tighter.
So loaded up a lot of 20 Cartridges with the following specs:

RP Brass, 123 grain Lapua Scenar, CCI BR-2 primers. Caces trimmed to 2.015, COAL 2.585.
Powder VV N550 39.7 grains to 41.6 in .1 grain increments.

Range 100 meters. And I ended up with a couple of Sub MOA groups...:o

http://i256.photobucket.com/albums/hh178/afy08/IMGP0437.jpg

Since shot 3 and 4 pretty much one holed, would I be right in assuming that 39.9 and 40.0 might be good loads? Simillarly shots 9 and 10, 14 and 15?
Or have I done it wrong?

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Grumulkin
December 28, 2008, 06:47 AM
The premise that you can shoot 1 shot of any load and draw any meaningful accuracy conclusions from it is laughable. And, by the way, how would you like to excuse shots 11, 12 and 13. I would also submit that 0.1 grain increments when working with a total load weight in the 30 to 40 grain load range is minuscule and pretty meaningless.

Was the point of aim the same for both groups? If so, there was a significant pressure buildup starting at shots 9, 10, 11, and 12.

Afy
December 28, 2008, 07:58 AM
The POA for shots 1-10 is the same, though different for shots 11-20.

No signs of pressure what so ever.

kelbro
December 28, 2008, 08:32 AM
Grumulkin is correct. Your tight groups demonstrate the need for stretching your ladder test out to a minimum of 200m. 300m is even better. Then repeat it once or twice. Up the increment to .2gr.

While you could probably pick a good load (or two or three) off this target, you will find that the additional range will narrow it down to the optimum load.

Ridgerunner665
December 28, 2008, 09:09 AM
What type of rifle is this???

I'm curious about the "hint" of vertical stringing in those targets.

Ridgerunner665
December 28, 2008, 09:12 AM
Never mind...I misunderstood your first post.

The stringing is there because there are no 2 rounds with the same powder charge...right?

NCsmitty
December 28, 2008, 09:56 AM
Afy, I think the 123gr Scenar is a great choice, but IMO, the .1gr spacing in loads needs to be widened to get definitive data. There are many issues, including human error,(no offense intended) that comes into play at that small differential.
I personally use .5gr differences to start, then I can concentrate on the series of charges that show promise and break those down finer if needed. IMO, it eliminates wasted time and components from the outset.
There are some fine target shooters on this site, and they have much more experience in actual competition than I. They will give you good info.

It looks like your rifle has a lot of potential and it won't be long before you have your load.
Have a great New Year and good shooting.

NCsmitty

Afy
December 28, 2008, 10:27 AM
Ridgerunner : Correct no two rounds with the same charge.
The rifle is a .260 Rem.

I currently am limited to a 100 Meter range until Spring at least. So that is going to be difficult.

Until ten, am going to try two groups of 5 each, at the following loads:
40 gr, 40.5 gr, and 41 gr. I do know that 41.7 gr groups consistently at sub-MOA so will throw that into the mix as well.

Claude Clay
December 28, 2008, 11:06 AM
friends and i have 5-k31's & a couple of k1911's.
made rounds 5 per gun on 2 gr increments starting at [varget, 168 gr bthp] 36 gr going to 46 [46.5 being a fed gold match match].
2 of the k31's are so accurate that we will work around the 42-44gr by .5 gr to find the sweetest load.

with each gun we threw the 1st round off target and counted the remaining--a called flyer would not be counted. 3 passes with a brass bristle & a hint of rem oil between groups.

1 round per charge weight may give some insight as to point of aim/POI but does not go towards group size.

-----cyber slow, i 'see' your post and seems you got the answer; good luck in the spring.

243winxb
December 30, 2008, 12:24 PM
+ 1 what NCsmitty said. Afy, the first group of 10 looks to be the best even with the .1gr powder changes. Shots 1 and maybe 2 can be from a clean barrel,or bags not settled in. My first shot always seems to go just a little high. I don't fire a fouling shot, bore is whiped dry after patching with Hoppies #9. Or do you fire fouling shots?:confused: As for testing at longer yardage, i see no need for that till you find the best grouping load at 100yds. Shooting groups of 5 shots is a good test. When you have what you feel is the perfect load, i would guess accuracy would average around 1/2" Good days a hair under, bad days up to 3/4" @100yds. Brass can be a big factor also. My best groups come when the unsized part of the neck has expanded to the chamber neck diameter when using bushing dies, 243win. caliber. So far your rifle is looking good.

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