Load development what do I do next?

[Lonewolf74]

Ok so I've been working on loads for 2 rifles using more a less the 10 round load development technique. Each round I fire has a half grain charge increase, I'm shooting through a crono to a target at 350 yards. My question is should I pay more attention to the chrono data or what the paper tells me?

For example (don't have exact numbs in front of me right now) in my 300 mag all rounds velocity increased 20-40 fps with each charge increase until the last 2, number 8 and 9. I actually got a 15fps loss in velocity with the increased charge in shot 9 so I'm thinking there's a node there. Velocity kept rising up to that point. However on paper there is about a 2" rise from shot 7 to 8 and another 2" rise from 8 to 9. I also got on paper shots 5, 6 and 7 on about the same vertical line but there was a pretty big velocity spread between these 3 shots. So based in the paper I would look at #6 charge weight but going off the chrono I think it should be #9 charge, which should I look closer at?

Also I never hit pressure signs with my charges so I could continue to increase a half grain for 2-3 rounds and see what I see.
So any input is appreciated

 

[savagelover]

why worry about the speed? It's the accuracy i'm after...Like an old fellow told me one time. Shoot'em slow and and put'em in the same hole..Only time I see speed important is in the wind..Think how slow an old lead round ball traveled..Killed a lot og game with that big slow ball..Anyway,I always try for accuracy first..A chrony is a nice tool to have..One you get an accurate load and check the speed it will let youknow how much drop you will have and how much you need the increase elevation..Just my thoughts on the subject..But what do I know?

 

[Lonewolf74]

Savagelover thanks for your response but I don't think you follow what I'm trying to do. I don't care much what the speed ends up being, obviously I want my load to perform well within the capability of the cartridge I have but I'm not looking to squeeze out all the speed I can.

I use the chrono looking for a velocity flat spot between 2 or 3 charge weights because in theory that should be a node. And in my way of reasoning this velocity flat spot should be confirmed on paper by very little vertical stringing of those shots.

However the problem I have is the paper isn't really reflecting what the chrono is telling me. I have successions of shots with little rise or even drops in velocity but a few inches of vertical stringing on paper. And I have the opposite where a succession of shots has 40-50 fps increase in velocity but very little vertical stringing on paper.

So my question is should I go off the chrono or the paper? I'd like to do both but I don't want to burn up that much time and resources.

 

[Rich Coyle]

Paper. Go for some more powder and see if you can get the chrono and the paper say the same thing.

 

[dsculley]

You are trying to use Scott Satterlee's method. For this to be successful you need VERY consistent load technique. Now, to answer your question: I will always believe my target over my chronograph. Of course, you have to critique your performance as well. I guess I should say that if I feel that I have executed my shots well then I will believe my target over my chronograph.

I would suggest that you load 3 rounds of each of those loads and shoot an OCW at 100 yds. You have already done a 300 yd ladder and it told you that your node is 5-7. See if you get the same results with an OCW. If you do, then load 10 or 20 rounds of #6 and take it to the longest distance you plan to shoot. See if the performance is acceptable for what you plan to do.

Don't try to overthink things. Trust your shooting and your target. Theory is good for discussion, but my target is always my final arbiter.

 

[L.Sherm]

Usually there is a lower node and a higher one. sounds like 5-7 maybe your lower one. If you had no pressure at 9 i would go up to 10 and maybe 11 and check the vertical a velocity plateau is usually a good node.

 

[Buck Buster]

You didn't say how long your barrel is or how much powder and type your using ,when your bullet speed stops increasing it could mean you are blowing the powder out the end of your barrel, ( not burning all of it ) . Good luck hunting and be safe.

 

[codyadams]

I would continue what you were doing, and work up until you find pressure. As stated, you will probably find a higher node. So say your loads came out like this....

1. 70
2. 70.5
3. 71
4. 71.5
5. 72
6. 72.5
7. 73
8. 73.5
9. 74
10. 74.5

And 8 and 9 had the best chrono readings, but were spread out on the paper. Was your shooting the same? Was your barrel getting warm, causing some mirage to distort the target? Or some other issue? That could cause the higher impacts. If your shooting form was solid, trust the target. What I would do is load this....

11. 75
12. 75.5
13. 76
14. 76.5
15. 77

And do the same method as you did. You will either find pressure, another node, or find that you still haven't found pressure. Either way, it is always good to KNOW where your max pressure is, that way you know how much wiggle room you have.

But say you find another flat spot in velocity at loads 11, 12, and 13, 14 has a rise in velocity, and load 15 leaves an ejector mark, with slightly heavier bolt lift, but still not a hard bolt lift. You can either pick a load out of the middle of 11-13, and shoot 5 shot groups at 100 or 200 yards, and stick with that if your happy, or if you REALLY wanted to get the most out of it, I would load this

1. 75.3
2. 75.6
3. 75.9
4. 76.2
5. 76.5
6. 76.8

And do the same thing. This will help you dissect your node, and give you the absolute best charge. After I do my ladder tests, I always shoot at 200 yards on a calm day, with a 3 or 5 shot group to confirm my load is accurate. I have yet for a load to perform well on my 500 yard ladder test and then not shoot good at 200, but anything can happen. It seems like a lot of shooting, but this part usually only takes me 15-20 rounds.

And that's how I do my load development....My last ladder I did actually gave me a 1.5" 4 shot group with 4 different charges that varied .3 grains each, with under 1" of vertical spread (at 500). Needless to say, the target made my choice of what charge to pick pretty easy.

Keep in mind, I do my ladder test AFTER finding my optimum seating depth. When you change your seating depth, it can change pressures, thus making your ladder testing void.

 

[Lonewolf74]

You didn't say how long your barrel is or how much powder and type your using ,when your bullet speed stops increasing it could mean you are blowing the powder out the end of your barrel, ( not burning all of it ) . Good luck hunting and be safe.

My 300 wm has a 26" barrel my load is the Berger hybrid 215 and RL26 powder.
My last (#9) shot was 77 grains RL26 velocity was 2945 shot #8 was 76.5 grains with velocity of 2960

 

[Lonewolf74]

Thanks for the replies guy's and I know what I'm gonna do next.

First I'm gonna get a beam scale to double check the charges from my rcbs charge master and make sure the charge is what I think it is and accurate.

Then I'm gonna redo my ladder starting at charge #6 and go up 1 to 1.5 grains past what I did before

 

[RockyMtnMT]

What chrono are you using? Will make a difference in whether or not I put more trust in the target or the vel data.

Steve

 

[Lefty38-55]

Look up Dan Newberry's "Optimal Charge Weight" (OCW) method ... it will resolve all your questions and give you PHENOMENAL results!

 

[dsculley]

For me it all boils down to: Do you believe your chronograph or your target? I do read and stay up on things in the shooting world. I understand the concept of Satterlee's 10 round load development. I understand ladder tests. I still prefer the OCW method when done correctly - 100 yds, 3 rounds per charge shot round robin. I don't think the 6.5 Guy's criticism of the OCW is valid. I have never had a problem finding a good node using Dan's OCW method. Some people will tell you that a load developed at 100 yds may not shoot well at longer ranges. I have seen that happen using the OCW method. For me, the downside to Satterlee's method is you have to be VERY consistent with your reloading process. Yes, we all strive for it but a minor error will effect the outcome. With a ladder test, a single errant shot, whether shooter induced or otherwise, can change the outcome of the test.

Another thing with the chronograph based tests - we don't test enough rounds to develop truly statistically significant results. If we did, we would lose too much barrel life. To see just how consistent your loads are, load up three sets of the ammo you are trying to test, then use these for three separate tests. Does your data agree across all three tests? I don't think you can run one set of test rounds over a chronograph and call it good. Just my opinion.

 

[Lonewolf74]

What chrono are you using? Will make a difference in whether or not I put more trust in the target or the vel data.

Steve

One of the pro chronos I believe it's called. The white one with the diffusers you shoot through. I know there not the most accurate out there so my actual velocity may be slightly different but I believe it's giving me consistent data and I never get a mis read or a way out in left field reading from it.