260 Rem Ladder test- Help understanding results

[seanhagerty]

I have a 260 rem that I am trying to work up a load for. I have shot basically the same ladder on two different days with similar results. I need help figuring this out.

The load

RP once fired brass
CCI LR Primers
H-4350
Berger 140gr VLD's

The load is 0.3 grain increments between 40.5 and 43.2 grains. On the first day I only went to 42.9grains. On the second day I started at 41.1 grains.

OAL was 2.950 +- 0.005"

These were all shot at 400 yds on different days. The results are similar, so I am pretty sure these are valid representations of where the charge will place a round.

I need help figuring out which charge to use.

Day 1

Day 2

 

[jcampbellsmith]

What I do to get some clarity on the ladder is to graph the results in Excel as attached. I then look at the graph and try to identify powder weights where the elevation hasn't moved dramatically. I then go away and retest any likely looking plateaus from the graph. On this graph I have circled 2 likely looking areas.

Good luck. JCS

 

[Hondo64d]

Great idea on using excel to graph results. I will definitely keep that in mind for the future.

John

 

[in2deep]

It really looks like it wants to shoot for you. The problem (good problem) is that with so many shots inside an inch it get's hard to refine too much since your node is fairly wide which is great. I would use the longer method of firing 3 rounds of each load in round robin fashion for loads "E" through "I" and that will smooth out some of the inconsistencies you have where the charges didn't repeat in order.
It's easier for my brain to process all the holes if I aim each group of 3 shots at different dots running accross the paper and you end up with a nice graphic displaying vertical groups which usually give a better average or confirmation that a single shot is not an outlier.
If you do the 3 shot test you will probably end up with a couple different loads (hopefully in order of increasing charge) that print waterline groups and this will further refine the good information you already have. You want a tolerant load so you choose a load that is in between 2 other groups so your not on the edge of a node but more in the middle to get a wider window that is not so critical to maintain. Google "Audette Ladder" tests and it will be better explained than I can do.
If your real confident some people will go down to 2/10 grain increments on the final ladders further refine the load.

 

[seanhagerty]

I am not sure what you are explaining. I understand I can decrease the charge seperation for 41.7 thru 42.9 grains (E thru I). Make up three rounds of eash weight then Round robin shoot them.

Do I set up three ladders with these loads? And run them side by side?

Or do I shoot each charge weight at a different spot?

Im easy. Plus I get to shoot.

Life is good.

 

[necchi]

Remember the ladder test isn't the end of it all, it's a method used to find accuracy "nodes" the rifle likes, there can be a few of these "nodes" found during any given test,, anyway's the test is just to get you close to what the rifle likes, then you work on the narrower window of charges and then play with seating and charge again to find the sweet spot.

in2deep touched on it, now it's time to work beyond the ladder,,
Shoot each charge weight at a different spot and see how they group''

Only I'd narrow the spread a bit, I'd go 41.7 through 42.3 (E-G) in .2 grain increments to narrow down any really nice nodes,,(41.7-41.9-42.1-42.3)

I changed to the Optimal Charge Weight system and found it much easier to nail down a load or at least narrow the specific load range.
http://optimalchargeweight.embarqspace.com/

 

[brian427cobra]

what are your repeatable chronograph numbers, and you might want to find another bullet, COAL of 2.950 is way beyond mag length.

 

[seanhagerty]

I agree. It is way beyond mag length, but I love that BC of the Berger 140 VLD.

I am looking to single load this for F class or from the bench.

Sean

 

[oneflyer]

Take a look at the ladder test/load development link on this website written by Jason Baney. I have used it successfully many times and I have deviated from it with less than satisfactory results. Its simple when used properly, will tell you immediately what load is best for your rifle and leaves you only with the simple process of testing seating depths. Saves you tons of time on the reloading bench, head scratching, and barrel life.

 

[JohnMill]

I'm with oneflyer. Read Jason's article and then read it again and then in a couple of days read it one more time. I have found several shooters on the range that did not understand how to do though they swore they had read it. It took only a few minutes to clear up their misconceptions. High lites are single aiming point. Rouund robin to spread the conditions equally. You're only trying to guage vertical dispersion. color only the front portion of the bullet. If you color the bearing surface the colors will combine in the barrel and it will all show up black. Longer range works better. 300 is almost too close.
Hope this helps someone.
Not to take credit for myself I got it from Jason and Frank Grappone at the BR school in Williamsport.
Pay it forward

John

 

[seanhagerty]

I thank you all for your help. I have settled on a load after playing with the Ladder test. 140 berger vld over 42gr H4350, gives me about 2700 FPS. OAL of 2.850"+-.005" I have shot 0.75" groups at 200 yds with it. I just need to do my part more better.......

 

[Erik Cortina]

OAL of 2.850" +- .005"

You need to work on loading more consistent ammunition if you want consistent and accurate results. .010" difference in seating depth can make a huge difference in accuracy.

 

[jcampbellsmith]

OAL of 2.850" +- .005"

Agree with Erik, I am aiming for less than +/- 0.002 inches variation in seating depth. Brass prep is the key thing to focus on. Also good seating dies. I read an article once that said that 4 thou was a significant change in seating depth. Reloading (and shooting) is all about consistency. Regards JCS

 

[seanhagerty]

Wow. Thanks for that. I will look at seater dies, got any good recommendations?

 

[Erik Cortina]

Wow. Thanks for that. I will look at seater dies, got any good recommendations?

Wilson inline seater.

 

[Yellow11]

... and another thumbs up for Wilson's seating dies

 

[Dirtfarmer]

+1 on the Wilson inline seater.

I like to have one cut when I build a new rifle. Both rifle chamber and Wilson Seater, cut with the same reamer, seems to work well, loading very concentric rounds.

DF

 

[joejo]

i just bought the forester micrometer seating die for the 260 and like it alot. i checked concentricity on the loaded rounds and found that it seats very true and have .0005 to .001 runout at the bullet ogive. also seating depths are all measured using a comparator and are spot on.
btw i would maybe try the 130 vld's, you lose some in bc but you can push them in the 3000 fps range.
mine is running 3050 out of an 8 twist 28 inch krieger

 

[seanhagerty]

I looked at the Wilson Seater. It says they need an arbor or hand press. I am not familiar with an arbor press. Don't have a hand press, the only one I know of is Lee's.

The Forester is an option for the equipment I have, I also looked at RCBS's micrometer type seaters. Anyone have any thoughts on them?

Sean

 

[Dgd6mm]

Out of those 2 I'd go with the Forster.