Ladder Test Analysis

[cmat1120]

Hello, I just finished up a couple ladder tests(I think that's the right term). Anyways I was looking for some second opinions on my data. The RL17 data seems pretty clear to me with a good flat spot at 41.4gr, but the H4350 flat spot at 41.5gr is a little too low of velocity. Should I test out to 43 gr to see if 42.7gr is a good spot? I don't really want to use a really hot charge as my final load, but I do want at least 2700 fps. Another option would be to switch to RL16(I want to get away from RL17 due to temp issues I guess). All brass showed zero signs of pressure(checked primers and around the shoulder/neck area).

The RL17 was pushing a 143 eld-x and the H4350 was pushing the 140 eld-m(I'm probably going to stick with the M based on terminal ballistics reports). All of them coming out of my Ruger American Predator chambered in 6.5CM with a 22" barrel. Also, this barrel had a total of 68 rounds fired through it before starting this test, so I do realize its possible fps will climb a little more over time, but it seemed to have leveled out before I started the tests.(Saw a 100fps rise in the 41.7 RL17 load from start to pre test and then it leveled out)

Charge-FPS
RL17:

39.6-2629
39.8-2629
40-2619
40.2-2656
40.4-2650
40.6-2666
40.8-2715
41-2699
41.2-2732
41.4-2715
41.7-2743



H4350:
40-2588
40.3-2574
40.6-2604
40.9-2619
41.2-2645
41.5-2640
41.8-2672
42.1-2699
42.4-2715
42.7-2732

 

[retired]

well charts and graphs are nice, where are the targets ?

 

[Jet]

#s and data are great but targets tell the tale. post some targets if you have them and you will get the help you are seeking.

Rich

 

[cmat1120]

Target was irrelevant in this testing(it was a rock lol). I'm doing my initial load development based solely on fps until I narrow it down to a good flat spot of low SD. If you've never heard of this method here's a good explanation

 

[David Christian]

Hello, I just finished up a couple ladder tests(I think that's the right term). Anyways I was looking for some second opinions on my data. The RL17 data seems pretty clear to me with a good flat spot at 41.4gr, but the H4350 flat spot at 41.5gr is a little too low of velocity. Should I test out to 43 gr to see if 42.7gr is a good spot? I don't really want to use a really hot charge as my final load, but I do want at least 2700 fps. Another option would be to switch to RL16(I want to get away from RL17 due to temp issues I guess). All brass showed zero signs of pressure(checked primers and around the shoulder/neck area).

The RL17 was pushing a 143 eld-x and the H4350 was pushing the 140 eld-m(I'm probably going to stick with the M based on terminal ballistics reports). All of them coming out of my Ruger American Predator chambered in 6.5CM with a 22" barrel. Also, this barrel had a total of 68 rounds fired through it before starting this test, so I do realize its possible fps will climb a little more over time, but it seemed to have leveled out before I started the tests.(Saw a 100fps rise in the 41.7 RL17 load from start to pre test and then it leveled out)

Charge-FPS
RL17:

39.6-2629
39.8-2629
40-2619
40.2-2656
40.4-2650
40.6-2666
40.8-2715
41-2699
41.2-2732
41.4-2715
41.7-2743
View attachment 1042685


H4350:
40-2588
40.3-2574
40.6-2604
40.9-2619
41.2-2645
41.5-2640
41.8-2672
42.1-2699
42.4-2715
42.7-2732
View attachment 1042684

How long is your barrel? I wouldn’t be too concerned with finding a higher velocity node, as hotter loads also equals a shorter barrel life.

You seem to have good flat spots with both powders. Why not test both flat spots in .1 increments (-.2, -.1, 0, +.1, +.2), 5 shot groups each on actual targets to see if the groupings confirm the FPS data?

 

[cmat1120]

Target was irrelevant in this testing(it was a rock lol). I'm doing my initial load development based solely on fps until I narrow it down to a good flat spot of low SD. If you've never heard of this method here's a good explanation

To clarify, based on this data I'd go back out with a target and play with small changes in charge and changes in bullet depth around the 41.5gr mark for H4350 and 41.4gr with RL17. I'm more or less just curious if these velocities seem accurate for these powders and a 22" barrel in 6.5CM. It seems to me like most people get between 2700-2800fps, but they probably have longer barrels as well. Looking at ballistics it looks like it might cut my max range for elk and deer by 50-75 yards each, which really isn't a big deal since I don't plan on shooting deer at 850-900yds and most elk areas in az seem too dense for shots over 300yds. I just wan't to make sure I'm getting as much as I reliably can out of my rifle and components because that's part of the fun of reloading for me.

 

[cmat1120]

How long is your barrel? I wouldn’t be too concerned with finding a higher velocity node, as hotter loads also equals a shorter barrel life.

You seem to have good flat spots with both powders. Why not test both flat spots in .1 increments (-.2, -.1, 0, +.1, +.2), 5 shot groups each on actual targets to see if the groupings confirm the FPS data?

Didn't see your post before making that post above, it's a 22" barrel. And that's exactly what I plan on doing. Looking at the ballistics the difference between 2640 and 2750 for elevation is .2 mil at 500 yds and finding somewhere to shoot further than that is a struggle of its own around here anyways

I may still try to get my hands on RL16 since I've heard such good things about it being more consistent and a little faster than H4350.

I really appreciate the confirmation on those flat spots. I think I'll probably do the -.2 through +.2 on the h4350 and with the RL17 I'll just shoot 5 of the 41.4gr. After that I'll play with bullet depth if there's any accuracy left to be desired. Should be able to get something dialed in before the middle of next month for a hunting trip which is what really matters lol.

 

[David Christian]

To clarify, based on this data I'd go back out with a target and play with small changes in charge and changes in bullet depth around the 41.5gr mark for H4350 and 41.4gr with RL17. I'm more or less just curious if these velocities seem accurate for these powders and a 22" barrel in 6.5CM. It seems to me like most people get between 2700-2800fps, but they probably have longer barrels as well. Looking at ballistics it looks like it might cut my max range for elk and deer by 50-75 yards each, which really isn't a big deal since I don't plan on shooting deer at 850-900yds and most elk areas in az seem too dense for shots over 300yds. I just wan't to make sure I'm getting as much as I reliably can out of my rifle and components because that's part of the fun of reloading for me.

@cmat1120 I have 2 different 6.5 CM’s. The first is a GAP Crusader that shoots lights out with a 26” barrel and it likes 39.9 grains of H4350 and it average 2740 FPS. I also shoot my current custom f-class gun with a 30” barrel that likes 41.2 grains of H4350 and it averages 2830 fps.

I think it is your 22” barrel that is giving you your perceived lack of speed. Seems about right for that short of a barrel.

 

[cmat1120]

@cmat1120 I have 2 different 6.5 CM’s. The first is a GAP Crusader that shoots lights out with a 26” barrel and it likes 39.9 grains of H4350 and it average 2740 FPS. I also shoot my current custom f-class gun with a 30” barrel that likes 41.2 grains of H4350 and it averages 2830 fps.

I think it is your 22” barrel that is giving you your perceived lack of speed. Seems about right for that short of a barrel.

Awesome, appreciate the info. I wanted a rifle with a medium-heavy contour barrel for target shooting, but still light enough for hunting so I knew I was going to have to compromise somewhere. As long as I'm getting the kind of velocity I should for the barrel I have I'm happy.

 

[22DASHER]

Target was irrelevant in this testing(it was a rock lol). I'm doing my initial load development based solely on fps until I narrow it down to a good flat spot of low SD. If you've never heard of this method here's a good explanation

That’s only a good explanation when it works and it does sometimes but not always. You should be utilizing your chrono as well as your targets. Your targets will trump everything else.

 

[cmat1120]

That’s only a good explanation when it works and it does sometimes but not always. You should be utilizing your chrono as well as your targets. Your targets will trump everything else.

I agree a flat spot in fps won't always equal accuracy on paper, but one of the key components to a small group is a low SD and this method helps me get that. If I could've set up a target as well I would've, but the place I tried today was not conducive to that.

 

[cmat1120]

Cmat1120
I've had flat spots in velocity during test as well that with further testing never came together group wise. You have had two responses to your post offering help that I would listen to. JMO
SPJ

No I completely understand that, like I said I have no expectation that just cause I have a flat spot I'll have a good group. They're just my starting points. I do appreciate the helpful comments, my plan is to go back out and do exactly what David suggested.

I just didn't appreciate the "if its not on paper its meaningless" comments as they were very unhelpful. I'm working with what I've got and if I can't shoot on paper the one day I have free to go shooting then I'm just going to work with what I've got. Today that was a chrono and a rock lol.

 

[dmoran]

What are using for a chronograph?

If your going to base your starting loads on SD, you need no less then 10-shots per increment.
If you want to do it more efficiently, with less costs of components and barrel life wasted, dispersion data to go along with the velocity data is a must.

Or so is my experience.
Donovan

 

[cmat1120]

I'm using a prochrono, and this test isn't giving me an actual SD. What it does is it finds the spots where there is little to no change in velocity versus change in charge. Within that zone the SD should be small since even changing charge weight has little effect. Of course I'll have to go into further testing using smaller increments and more shots per increment, but instead of taking 100 shots I'm taking 10 and then 50(if I'm taking 10 shots per increment). That's the idea at least. This is all a learning process and I really like the theory and science behind this method so I'm giving it a go. If it doesn't work out then oh well, I get to go shooting more to continue load development. And like I said before, if I could've recorded dispersion data I would've but I didn't have somewhere to put my target. I also didn't have enough brass. I had to use half my brass just to break the barrel in enough to start shooting consistently today. To test this wide of a range of charges like that I would've needed twice the brass I own and more time than I have free(I might be spending more time than necessary letting my barrel cool, about 2 minutes a shot or 10 minutes per 5 shots)

 

[CharlieNC]

With each velocity you measure and plot, there is an associated es and sd. You may not have taken enough measurements to calculate, but it is there. So there is an error band associated with each point, and likely the "flat spot" you seek to identify is just luck of the draw. Before you make a significant decision to move forward, repeat the trial to see if it replicates. I would be surprised if it did.

 

[Raythemanroe]

Here is something that may help with the "ES" crowd, I know it won't change the minds of juice drinkers.. You shoot through your chrono and get a group /ES that performs excellent.. You setup at longer distances and still looking good.. Then temps go up and the environment pushes that low ES load you had off into la la land.. This is where I feel a ladder test that you visually see a cross reference of powder charges printing similar at that given distance will show you a much more forgiving/consistent load.. Yet not always the lowest ES either..


Ray

 

[dsculley]

One thing about the method you have chosen, your reloading skills/technique have to be top notch and you need a very accurate chronograph as well. Even a +/- error of 1% will provide erroneous information with just one string of shots. I know this is an appealing method for technically minded shooters, but it does have downsides as mentioned. On the other hand, I have never seen a properly developed OCW load that did not shoot well at range.

FWIW

 

[Nude nut]

Hello, I just finished up a couple ladder tests(I think that's the right term). Anyways I was looking for some second opinions on my data. The RL17 data seems pretty clear to me with a good flat spot at 41.4gr, but the H4350 flat spot at 41.5gr is a little too low of velocity. Should I test out to 43 gr to see if 42.7gr is a good spot? I don't really want to use a really hot charge as my final load, but I do want at least 2700 fps. Another option would be to switch to RL16(I want to get away from RL17 due to temp issues I guess). All brass showed zero signs of pressure(checked primers and around the shoulder/neck area).

The RL17 was pushing a 143 eld-x and the H4350 was pushing the 140 eld-m(I'm probably going to stick with the M based on terminal ballistics reports). All of them coming out of my Ruger American Predator chambered in 6.5CM with a 22" barrel. Also, this barrel had a total of 68 rounds fired through it before starting this test, so I do realize its possible fps will climb a little more over time, but it seemed to have leveled out before I started the tests.(Saw a 100fps rise in the 41.7 RL17 load from start to pre test and then it leveled out)

Charge-FPS
RL17:

39.6-2629
39.8-2629
40-2619
40.2-2656
40.4-2650
40.6-2666
40.8-2715
41-2699
41.2-2732
41.4-2715
41.7-2743
View attachment 1042685


H4350:
40-2588
40.3-2574
40.6-2604
40.9-2619
41.2-2645
41.5-2640
41.8-2672
42.1-2699
42.4-2715
42.7-2732
View attachment 1042684

Carry on your on the right track but as it ha been said try use a target I did a ten shot load test last thursday with my new 308 barrel with my new labradar then friday just gone loaded 5 rounds where I thought I should be shot them at 100 yards got one hole.
Loaded 24 rounds for club match Saturday shot them at 900yrds clean barrel my es was 12 and my sd was 4 I think or 4.1 and that included my 2 sights so that's 12 rounds.
Am I finished load testing NO the second round after the temp reached 37 c my e's jumped to 20 a bit more tuning I think so it does work to a degree.
But it's funny how we get told numbers never lie and their relied upon for just about everything in life but you mention load data and crony said this it all of a sudden is a lie don't mean nothing.
Oh I won the day with my off hand score.
Cheers Trev.

 

[dmoran]

To go off velocity data exclusively, the type of chronograph and there setup, will determine how factual the resultant data will be. Especially with "eye sensor" types, where setup and lighting control is critical.

Have used and tested many chronographs over the years (have tested as many as 7 inline at one time). From which (IMO) there are some that I feel don't have the accuracy and/or consistency to do such testing justice. And some that will only do so, if "false lighting" is implemented in there setup.
Donovan

 

[cmat1120]

I appreciate everyone's comments and I respect that you don't all agree with my approach. However, that's not really something I was asking about. I'm trying this method because I wan't to. I don't care if it's not the "best" method or if I should be doing it differently according to ____. All I wanted was to know if my data seemed reasonable and I got a few responses that addressed that directly which I appreciate a ton. I understand even the people telling me I need to do everything differently are still trying to help, that's just not what I wanted in this thread. I understand I'm new to this forum so I'm not trying to just brush off the help of those more experienced than myself. I just want to learn on my own with a little confirmation that what I'm doing made sense so far. Thank you all.