Need help with reading ladder tests

[ssteve]

Got a new 6.5cm and ran 200 rounds of factory match through it, now I am trying to pin down a couple loads. I loaded up four 10 round ladders with two projectiles. So two ladders duplicated so I could see how they compare to each other and possibly weed out inaccuracies in my reloading.

First two ladders were 136gr scenar L's, h4350, cci 250

41.6 2696** 2686
41.8 2686** 2728
42.0 2744** 2735
42.2 2722** 2748
42.4 2736** 2754
42.6 2766** 2787
42.8 2747** 2787
43.0 2788 2767
43.2 2830 2827
43.4 2812 2827****slight primer cratering

**first seven rounds fired my magnetospeed was loose so I don't trust that data. I'm thinking 42.6 looks like a good place to work around and possibly see what 43.2 has to offer?

Second ladder was also h4350 and cci250's but with Berger 130 vld hunting projectiles.

41.8 2678 2682
42.0 2701 2703
42.2 2705 2737
42.4 2759 2728
42.6 2734 2751
42.8 2782 2772
43.0 2776 2776
43.2 2801 2802
43.4 2797 2821
43.6 2827 2826** very very slight primer crater.

This ladder I am thinking 43.2gr looks like it has potential? Maybe even 43.6 since it will be a hunting load? First round at 43.6 doesn't show any pressure signs but the second one does and I think thats possibly cause the gun was hot and I let it cook in the chamber for a little bit before I sent it down range.

I plan to hunt with bot rounds. The scenar L will be my range bullet as well as varmint and predator round. The Berger hunting bullets will only be used for pig and deer.

These were all loaded up .025 off the lands.

 

[sandwarrior]

A ladder should tell you three things if you can get range long enough to accomodate you.

1. Pressure. -check, you've accomplished that with a good powder.

2. Drop. If you can get a long enough range, it will show a range of powder loads that will run in the same velocity. The reason this happens is powder speed/pressure vs. room to burn. In any case it helps if you note this. 300-400 yds is optimal if you can get it.

3. Accuracy. Not only are you looking for that little window in which up to a grain of powder either way, will get you the same velocity, so your drops at distance are very consistent, the general accuracy of the load is important. 100 yds. is all that's needed for this, but the longer range noted above can be used as well. How did your loads fare for accuracy?

 

[spife7980]

I don’t see any ladder test results.
Instead of hoping for good numbers to luck you into accuracy you should be looking at what the target 500 yards away says. The paper is your primary concern, numbers are ancillary data.

 

[ssteve]

I was attempting to do a Ladder via the Scott Saterlee method, pin down a node I wanted to play with and then see how that grouped. The closest range to me only goes to 300 yards so I just put the 40 rounds down range today at 100, then pick a node and see what it groups at 300. The groups were about 1 1/2" for ten rounds so I am sure whatever charge I pick will group decent at 100. Its just a matter of getting something that will shoot at distance when I don't have distance to shoot out to.

 

[spife7980]

Shoot an ocw then

 

[sandwarrior]

I was attempting to do a Ladder via the Scott Saterlee method, pin down a node I wanted to play with and then see how that grouped. The closest range to me only goes to 300 yards so I just put the 40 rounds down range today at 100, then pick a node and see what it groups at 300. The groups were about 1 1/2" for ten rounds so I am sure whatever charge I pick will group decent at 100. Its just a matter of getting something that will shoot at distance when I don't have distance to shoot out to.

At 1-1/2" I'd work on your technique of shooting at 100. A new rifle should do much better than that.

When I bench shoot for groups I shoot five rounds without moving my head or body. The only thing that moves is my hand to extract and chamber cartridges. If you are not in a position to watch the bullet make impact and not have to move around to get back in position, find a way to get that position. You really need to narrow down the accuracy for either a ladder or ocw to work.

 

[ssteve]

10 round group with 10 charges and an ES of 140+? I figured a inch and a half cluster would be about typical. Maybe not. Pretty sure my technique is decent as the gun shot Norma 130gr match at about .600-.750 at 100 and a couple at 300 just under moa before the wind picked up.

I’ve shot 280 rounds through it now with a majority of the ammo being Norma match and it shoots good.

I think of anything needs work it’s my reloading.

 

[ssteve]

At 1-1/2" I'd work on your technique of shooting at 100. A new rifle should do much better than that.

When I bench shoot for groups I shoot five rounds without moving my head or body. The only thing that moves is my hand to extract and chamber cartridges. If you are not in a position to watch the bullet make impact and not have to move around to get back in position, find a way to get that position. You really need to narrow down the accuracy for either a ladder or ocw to work.

Maybe I’m saying it wrong then cause I thought that was the whole point of the Scott Satterlee method? Accuracy isn’t really a concern, just finding a charge weight that allows for low ES’s? Then once you find that node refining it for accuracy....?

 

[sandwarrior]

10 round group with 10 charges and an ES of 140+? I figured a inch and a half cluster would be about typical. Maybe not. Pretty sure my technique is decent as the gun shot Norma 130gr match at about .600-.750 at 100 and a couple at 300 just under moa before the wind picked up.

I’ve shot 280 rounds through it now with a majority of the ammo being Norma match and it shoots good.

I think of anything needs work it’s my reloading.

These are the things you gotta tell us. So you know factory match is working good. Have you thought about trying to duplicate that? Norma GT's? i assume?. Have you pulled a factory load for powder weight? Did you come close to seating depth of factory? have you checked velocity of factory? Have you compared drops from yours to factory? Reason being, harmonics of the barrel plays a role here too. It's not just how much velocity is attained, it's how fast or slow it's attained, and how that affects barrel harmonics.

FWIW, your factory loads giving you what they do is the perfect example of OCW. Also, it's what you are trying to find out when running a ladder. I like ladders because they show all node potentials not just an OCW at the highest node. Which, is not where you should start when reloading for a rifle the first time. After you work up a load and find an OCW, then you can start there on future batches. As long as you know you have a safety margin with it.

Accuracy is a concern. If you have shot dispersion at 100, you're going to have shot dispersion at distance. You want accuracy in the end, as much as ES.

 

[ssteve]

Yeah the Norma stuff is loaded with the GT projectile. It’s loaded pretty short so the jump is pretty drastic. Its coming out at right about 2800 but ES’s are not that great, usually in the 40’s. More rounds in the 2780 range but seen plenty in the 2830’s also. Groups great at 100 but I am pretty sure I can see the poor ES starting to affect my groups at 300. When I get a group with a good es it’s tight, when I get a group with an es of 40+ it opens up some. Unfortunately I don’t have a further distance to shoot out to.

 

[Fig]

I don’t see any ladder test results.
Instead of hoping for good numbers to luck you into accuracy you should be looking at what the target 500 yards away says. The paper is your primary concern, numbers are ancillary data.

I.E. - There is no chrony, program, AP, test, etc. that will replace DOPE. Proof of how the rifle shoots in a given condition is the superlative data and result, period. Everything else is an aid to get good DOPE more quickly.

 

[sandwarrior]

Yeah the Norma stuff is loaded with the GT projectile. It’s loaded pretty short so the jump is pretty drastic. Its coming out at right about 2800 but ES’s are not that great, usually in the 40’s. More rounds in the 2780 range but seen plenty in the 2830’s also. Groups great at 100 but I am pretty sure I can see the poor ES starting to affect my groups at 300. When I get a group with a good es it’s tight, when I get a group with an es of 40+ it opens up some. Unfortunately I don’t have a further distance to shoot out to.

Hodgdon's website is a little screwy on this. It has 39.2 gr. as the max for a 130 gr. bullet and 40 gr. as the max for a 140. Since both your loads started above that, where did you get your start info? Extreme high pressures do affect barrel harmonics and how the powder burns as well. However, since you are not seeing overly high pressures until you noted so, you might change seating depth or primers to see if that will help? Hodgdon has gone way conservative on their numbers as of late.

Also, what kind of rifle with what barrel length do you have?

 

[lash]

Op, I read your posts as indicating that you shot 1-1/2" group at 300. If that is the case, maybe it was missed by a few people posting above. It might help if you verified if that's true or not.

 

[sandwarrior]

I was attempting to do a Ladder via the Scott Saterlee method, pin down a node I wanted to play with and then see how that grouped. The closest range to me only goes to 300 yards so I just put the 40 rounds down range today at 100, then pick a node and see what it groups at 300. The groups were about 1 1/2" for ten rounds so I am sure whatever charge I pick will group decent at 100. Its just a matter of getting something that will shoot at distance when I don't have distance to shoot out to.

ssteve,

As lash noted, I may have misread this. Your 1.5" groups were at 100 or 300? If at 300, my comments about accuracy do not apply. You would have the needed accuracy if that is the case.