Help interpret a ladder test

[jonaddis84]

Bottom two groups are the first stage of the ladder test. Left is 40.5-45.0 in 0.5 increments. Right is 40.7-45.2 in 0.5 increments.

I liked 7,8 and 9 (43.5-44.5) the best out of both of those, so I loaded up stage two. Top left is 43.5-44.5 in 0.2 increments. Top right is 43.4-44.6 in 0.2 increments.

It was going really well for the first stage, but stage two has me stumped. These were all shot from 300 yards, no windage accounted for, and by the time you subtract the .30 for the group size they are both sub half moa and all different powder charges!

I loaded up 10 rounds at 44.2 (#5 top right) to see how they group, havent shot them yet.

These are all loaded .010 into the lands on a factory barreled recently chopped to 18.5" Savage 12. The action was just trued, a sharpshooter lug installed, and the stock re-bedded with Devcon. So I really dont expect a hell of a lot better than .5 moa anyhow, it'd be nice, but I'm being realistic knowing its a factory barrel.

What would you pick for a load to try?

 

[vman]

Re: Help interpret a ladder test

7, 8 and 9 are consistently showing similar results, in both of your main ladder tests.

I would ditch any further ladder testing to save on your sanity, and comence confirmation testing by just shooting groups out to 300.

43.4 to 44.6 in 0.2 grain increments, and 5 shot groups.

Thats 35 rounds worth.

Also, what projectile and powder?

 

[vman]

Re: Help interpret a ladder test

Also where is shot 7 on the top left hand target?

IF your shooting the 175smk with Varget, then I can see you are coming close a typical accuracy node for that combo. Ignore this statement if thats not 175smk/varget

 

[jonaddis84]

Re: Help interpret a ladder test

Some background:

175 SMK
Varget
Lapua brass
210M

The reason Im developing this load is I was previously loading 44.6 and jumping .020, when for some reason I started getting pressure signs after a few months of using the same load. Stupid me forgot to redo the load when I started a new lot of powder.

44.6 still seems on the edge of pressure with this lot of powder, so Id like to stay closer to 44 just to be safe, Im sick of ruining my friggin lapua brass.

There is not shot #7 on the top left, I didnt really want to go any higher than 44.6 and didnt see the need to go lower than 43.4 since I dont want that low of velocity anyway.

This is probably the 3rd or 4th time working up a load for this rifle, but the first time Ive tried the ladder test.

 

[m1ajunkie]

Re: Help interpret a ladder test

I have been developing a load for my .308 with the 175 and varget and found that 43.4gr is shooting very well. I have heard that different lots of varget shoot slightly different, but what kind of variation should I be looking out for?

I have been using 1lb containers until I knew the varet was good to go. Will I have to totally rework my load when I get into an 8lb container or should I be able to shoot a couple groups and verify that I am still good to go?

 

[bowslngr]

Re: Help interpret a ladder test

Throw away the rest of the clutter and focus on the relationship between shots 2, 3 and 4 in each of your refined ladder tests. I would go with 43.8 or 43.9 grains.

 

[ChadTRG42]

Re: Help interpret a ladder test

Ok, here's my perfect point on this "ladder method" of load work up. You've fired ~33 rounds on target at 300 yards in 2 range trips and don't know a thing on your loads. You have no information on the consistancy of the load (how tight it shoots) or velocity extreme spread of that load. And where are you at. Ok, you might know a little bit about where to start your powder charge tests. But it took you ~34 rounds and 2 range trips to get there. The 308 Win with a 175 SMK and Varget is not a mystery. It is probably the most known reloading combo out there with the most data. So, why a "ladder method"?? We know that 45 grains is about max for this combo. Load up 5 rounds each starting at about 43 (or even 44) grains, and work up in .3 grains til you find a sweet spot. That's 35 rounds, and now you will have data on how consistant your load is (how tight it shoots), and velocity data (extreme spead). And all of this can be done in 1 range trip in about 25-35 rounds. I truely am mistified about this method on why people use it. I see more and more threads on "interpret my rounds", and "tell me which load to try next".
OP- I'm not directing this at you. I think this method of load work up is wasteful, and has been posted way too many times.

 

[jonaddis84]

Re: Help interpret a ladder test

Im on the same page as you now Chad. I had never tried the ladder test, always read about it so I thought I'd give it a shot. I do think that it could be useful on long barrel guns (25"+), where you will get quite a bit of barrel flex when it is vibrating, but an 18" stick probably just doesnt flex enough for this test to work properly.

Honestly I couldve known just as much with this test had I only loaded half, but I havent shot in so long I just wanted more rounds to shoot, thats the only reason I did two groups in each stage.

To the guy using 1lb Varget, I would at least only load 5 or so rounds from the new lot before you go loading a bunch up and just make sure you dont have any pressure signs and that they are still grouping. I was in the same boat, using 1 pounders, but I finally got my hands on an 8lb jug.

 

[coues7]

Re: Help interpret a ladder test

I'd focus on your upper left group.

 

[bm11]

Re: Help interpret a ladder test

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: m1ajunkie</div><div class="ubbcode-body">but what kind of variation should I be looking out for? </div></div>Last lot to this one, I dropped 50 fps in the same load. I bought 24 pounds, so I don't need to worry about this again for a while.

 

[jonaddis84]

Re: Help interpret a ladder test

44.2 it is! 300yd group in gusting 10 mph wind.