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Posted: 4/11/2013 4:29:41 AM EDT
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Short Version: Do you test to the sweet spot and a few rungs past it and then stop or do you shoot the entire ladder?
My thoughts and why I am asking: I have not really needed to work up a ladder before as most of my loads have been starting loads that worked or pet loads from people I trusted. I am now getting into the experimental side loading for the .300 blackout trying bullets that either don't have a lot of data or none at all. Factor in differences like the barrel length, suppressor use, etc testing it yourself is the only real way to know. With the price of powder/bullets I am trying to conserve as much as possible. I found the starting load for a similar bullet and worked up 50 rounds. 10 steps in .2 grain increments, 5 rounds each. What I am curious about is while testing, if I start at the bottom and work up and find on say step 4 that I am getting accurate results and then it gets worse after is there any reason to keep going? Would you stop and rework the remaining rounds around the step 4 load? I am thinking that if say 5-7 start deviating that its not going to get better by 8-10. 10 is the max load recommended for the comparable bullet anyway. My thinking is that I could use the remaining rungs, pull the bullets, dump the powder, resize if needed, and reload them with rung 4 data +/- .1gr increments to see if there are improvements using smaller steps. |
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I research and know where the likely sweet spot will be (based on posted data from others on this and other forums), so I load most of the ladder
below that number, hit the "supposed sweet spot", then go one or more rungs past the sweet spot. This works for me. I generally shoot ALL of my ladders b/c I'm an optimist and believe that the next one COULD be the best one yet! 
-ZA ETA: I also shoot ALL of my ladders b/c I don't make pet loads for specific rifles. I like to have "common" good loads for both of my 5.56 AR's, and both guns run the exact same ladder loads (gets time consuming doing everything 2X). I make the decisions on which load is best based on comparing the results of the two guns. Most of the time, they will both love the same exact load. Seems like a "node is a node" in my guns. If one of them hates a particular bullet or powder combo, I'll move on to a different combo to try to find a different common load. |
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I am not as lucky on some of what I am prepping to do. There is not a lot of data on the bullet/powder combos that I am working with and the sweet spot is not listed. To limit the variables I am dealing with 1 rifle right now and I will probably not be adding another for a while. My plan is to work the load up for this rifle and if I get another I can work from its sweet spot.
I guess my bigger question is if you test the load to 100 yards and once you are past the sweet spot, is it likely that there is a second sweet spot? I understand ballistics/optics and how if you sight to 25 yards that you can be 2inches high at 100 yards and drop back to zero at 300. I am just trying to figure out if anyone has seen loads work the same way. For the .300BLK there is not a lot of wiggle room as the difference between my starting load and max is roughly 2 grains of powder or so with the bullets I am testing. |
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To really settle one's mind, I think a full ladder is necessary for two reasons. First, I have found that some cartridges have multiple points of low E.S. Usually, these points are not too far apart, but they are sometimes clearly separated by a load that is not near as consistent as those above and below it.
Second, the harmonics of your barrel, rather than internal ballistics, will usually determine accuracy. You might have a fantastic load, with extremely low E.S. that goes at just the speed your rifle does not like. So, for these reasons, covering all the bases is the only way to assure yourself that you've found the point of best performance for a given rifle, bullet, and powder (to say nothing of bullet seating). |
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Quoted:
I guess my bigger question is if you test the load to 100 yards and once you are past the sweet spot, is it likely that there is a second sweet spot? From my research, it seems that most barrels will have multiple harmonic "nodes" where they will show optimum accuracy. Bullet speed, bullet weight, barrel length and barrel stiffness are some of the main variables. So to answer your question, yes, there is more than one sweet spot generally speaking. However, those other nodes may or may not not be practical for various reasons (too hot or too light of loadings). -ZA |
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