Load Development (Part 1 of 2)

LoadTargetsOne of the most pleasurable parts of our journey is coming across folks who look at established methods and re-evaluate them asking if there is a better way. Load development is one of those areas where opinions and approaches vary widely. Shooting forums are replete with users throwing up groups and asking other users to interpret them because they lack an objective method.

We have been presented with an approach which we believe is objective and fact based, and corroborates some of the things that we have observed during our own load development. It’s an approach that we want to share with our audience for their consideration.

Many of our viewers are familiar with the Optimal Charge Weight (OCW) method popularized by Dan Newberry. Ed paid Dan’s consulting fee to help him develop a load and received valuable advice. Dan’s approach has lead us to some accurate loads, but there are some aspects of the approach that shooters should take into consideration:

  • OCW does not account for variances in group spread attributable to shooter error. An OCW target resembles a dot drill and few shooters, even with the same load and unlimited time, can shoot a perfect dot drill. The round robin method, which is intended to reduce shooter induced error, may actually exacerbate shooter error because it resembles a dot drill exercise.
  • OCW does not account for variances in muzzle velocity that may result in relatively tight groups at close distances but may open up at long ranges. Adherents to the approach are told to focus on group size and this presents a problem at longer distances as velocity variations lead to vertical dispersion. This is not opinion but mathematical fact – just consult your ballistic calculator. As such, velocity variations have to be taken into consideration and minimized.VelocityVarianceChart

Scott Satterlee, owner of Precision Tactical Solutions, paid us a visit to explain his approach to load development. Scott is active duty military and actually shoots for a living (some people have all the luck) and trains special operations personnel. His training is available to civilians – we took his training in December of 2013 and it was a game changer for us. But we digress…

Scott divides his approach into the following phases:

    • Phase 1 / Step 1: Establish COL for your chamber where the ogive engages the lands. Back off .020″ from this length to establish a baseline COL for a starting load. There are a number of ways to do this. In the video Scott describes how to do this without using any special tools. Note: For VLD bullets we kiss the lands and call it a day. On Berger’s web site, some shooters are reporting better results when jumping VLDs but this seems to be the exception rather than the rule.
    • Phase 1 / Step 2: Load test rounds, 5 cartridges per charge weight (start at 15% below target accuracy load and work up in .3 grain increments to 10% over target accuracy load). Target accuracy loads can be obtained from a number of sources, the most reliable being the gunsmith who built the rifle.
    • Phase 2: Fire and chronograph test rounds in 5 shot strings without breaking your position. In other words, fire each group of 5 loads into one target before moving on and completely rebuild your position between targets. Do not shoot round robin, but instead randomize the order of the loads that you shoot. Allow time for your barrel to cool. It helps to bracket your reticle versus floating it over a dot.
    • Phase 3 / Step 1: Identify the load group with the smallest SD/ES velocity variance and compare to POI spread on target. You will see a high correlation. Note: When we’ve used the OCW method in the past, our most accurate loads have always been the ones with the lowest SD/ES.
    • Phase 3 / Step 2: Chart muzzle velocity groups and identify flat areas of the curve. Charting the results in a spreadsheet makes it easier to see the flat areas. You’ll want to find a load that is in the center of the plateau as it mitigates the effects of variations in powder charge, temperature, etc.

LoadChart

    • Phase 4 / Step1: Load 5 rounds up and down from the optimal load by .1 grain increments to .2 above and below. Measure the velocity and group size to find the very middle of the curve.
    • Phase 4 / Step 2: Once the mid point of the velocity curve is established, modify seating depth of loads (3 rounds) in .005 longer increments until the load is touching the lands. Note: VLD shooters who are kissing the lands already would eliminate this step. We advise against jamming the bullets into the lands as that can create a mess if you need to remove an unfired round from the chamber – the bullet will be stuck in the barrel and powder will get in your trigger.

In part two of this series we will use this methodology to evaluate several loads. Stay tuned!

Latest Comments
  1. Jim Shepard

    Great discussion on load development. I have gone through the ladder and OCW testing and really wondered if it is really worth it. Here is my observation, why even shoot at the target, just measure the velocity of the different loads, find the plateau, refine the loading on that shelf, then tune the rifle (zero the scope) to shoot at that load? Since, (as you identified in the video) shooter variables can cause groups to open, removing the human element seems to be a gained efficiency.

    Finally, can you Excel wizards walk me through a method to plot a predicted muzzle velocity curve (line) with collected velocities in a scatter plot over the predicted curve. Excel should be able to do this but the process has eluded me. great show.
    Jim

    • 65guys

      Hi Jim,

      You are spot on. I’m getting ready to work up some loads and I don’t have a lot of time. I’m just going to look at my chronograph results and go from there. I’m going to strap on my magnetospeed and practice some positional shooting. Much better use of time and components IMHO.

      Regarding the spreadsheet, I’m going to defer to Steve as he’s the Excel Wizard.

      Regards,

      Ed

  2. Dan Newberry

    Interesting program! I think you guys have something good going here, keep it up.

    If I may, I’d like to address a couple of the concerns for OCW load development that you mention.

    First of all, as to velocity… a properly interpreted OCW test will not lead you to a load that has high velocity spreads owing to the powder charge alone. This is not to say that you can’t get poor velocity spreads during an OCW test, but this is something that would need to be fixed with better case prep, primer selection, etc. The OCW powder charge won’t be at fault in this case.

    And as to… shooter error. True, if the shooter isn’t doing his best, it’ll show up on the target… BUT 😉 …it’s easy enough to see the shooter induced flyers since they don’t trend toward or “point to” a new POI (point of impact) location. In other words, let’s say you have a high left flyer in a 3 shot group, and neither the charge weight below that point, nor the charge weight above that point is putting shots in that odd location. The remainder of the data in the OCW test will show us whether this flyer is in the scatter node area or not. If it’s not–it’s shooter induced 90+ percent of the time and needs to be understood as such as the results are interpreted. Granted, it could be a bad bullet or case or such… but it’s not the fault of the powder charge, regardless. I do encourage OCW clients to keep a 4th round of each charge weight in the test box in case he knows he pulled a shot.

    If you guys would like to start from scratch with a new load recipe, choosing the powder and bullet, I would like to work with you (free of course) as you develop at 100 yards… then take it straight to 1000. Straight to 1000 yards, no passing go, no chronograph data whatsoever… and let’s see how it looks. We will want to do an OAL phase of the test after the initial OCW powder charge work-up, but other than that, take it long and let the target decide. What do you think? 🙂

    • 65guys

      Hi Dan,

      Awesome to hear from you! As I (Ed) mentioned in the video you helped me out in November of 2013 with my .260 load. To your point, all of the optimal loads we have identified to date have had low SD and extreme spread.

      We would enjoy the opportunity to collaborate so will be reaching out to you. It would be great to work something up from scratch. We’d also be interested in your perspective on our practice load: http://www.65guys.com/developing-a-practice-load/

      Regards,

      Ed

  3. Greg Bishop

    Great article!! Always nice to see other ideas

  4. Sten Moeller

    LAH-puh-ah, Gentlemen, not, Le-POOH-ah. The Finns deserve that respect :-).

    • 65guys

      Yes you are correct – and you’ll see we’ve gotten better in our most recent videos. Thanks for watching!

  5. Tim

    Good points brought up here guys, thanks for bringing them to the fore. I also appreciate Dan’s input on what’s been said. Shooter induced error is something I wrestle with when doing these tests, especially with higher recoiling rounds like the 7mmRM or even the 270. As mentioned, positioning affects POI. But another thing I’ve been thinking about and researching is the effect of how much resistance we apply to the rifle’s recoil, and how that affects MV. It turns out that has quite a measurable effect. So if you’re not consistent in how tight you’re holding, and of course the lighter the rifle and heavier the charge, the more effect this has, you will see a greater spread in MVs. I have found shooting the same loads prone gives me lower ES and SDs than shooting from a bench.

    • 65guys

      Hi Tim,

      You are spot on. While we worked from the bench while filming our load development videos, we prefer to shoot from prone for the reasons you described.

  6. Peter A Wierenga

    I am confused. The video of Scott talking about his velocity testing system uses about 30 rounds to come up with a good load…10 initial rounds, 5 more each at two other weights and then another ten to confirm.

    But the text above under Scott’s name is COMPLETELY different, saying this:

    “Phase 1 / Step 2: Load test rounds, 5 cartridges per charge weight (start at 15% below target accuracy load and work up in .3 grain increments to 10% over target accuracy load). Target accuracy loads can be obtained from a number of sources, the most reliable being the gunsmith who built the rifle.”

    But if I follow that process I calculated that I would need to load just under 200 rounds to try out…5 rounds at .3 grain increments starting 15% below max charge (for my purposes I would start at 37 gr.) and going to 10% above max charge (which would be 47.8 gr.). So that is 36 increments of .3 grains and 5 rounds per increment or…180 loaded rounds to BEGIN the load development.

    Can you help me reconcile the huge difference between the video with Scott and the comments in the “load development” post above?

    • 65guys

      Hi – We just published a written article on the web site that should alleviate the confusion. He only loads 5 rounds within the accuracy node. Thanks for watching!

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