Velocity ladder es/as ?started at

[earlcurtis67]

so I did a quick velocity ladder on Sierra 52g HPBT (#1410) I started at 23.5 and ended at 25.9 using LC brass , 450 primers and 8208. Brass necks were skim cut and powder was carefully measured. Below are the chrono readings. I know that getting good ES’s w a 223 is difficult but there isn’t really a flat spot to go from, is this “normal” or should I scrap the 8208 and try a different powder. I would prefer to stick with only one 223 powder since it shoots the 69SMKs very well. I’m not looking for bench rest accuracy just a varmint/paper gun. Thanks in advance. E

23.5 2891
25. 2913
24.1 2982
24.4 3001
24.7 3049
25 3110
25.3 3190
25.6 3210
25.9 3292

Factory savage 9 twist

 

[Ned Ludd]

A "flat spot" in the velocity curve isn't always easy to spot, especially in a cartridge with small capacity like the .223 Rem. Sometimes using a different primer will make it more obvious. Regardless, I've often found the charge weight window for .223 Rem with heavies (80/90 gr bullets) to be quite narrow, often 0.3 gr or so, which is the charge weight increment you used in your test. Observing a minimal (or zero) velocity change over 0.3 gr or more (i.e. two successive charge weight increments in your test) is asking a lot for such a small cartridge.

I'd suggest using a smaller charge weight increment, perhaps 0.2 gr, and using either a traditional ladder test or Optimal Charge Weight (OCW) approach. Although subtly different in how they're carried out, both of those approaches are based on finding the charge weight region associated with the most consistent point of impact on the target. In other words, if you aren't seeing a velocity flat spot, perhaps velocity isn't the best indicator. You may well have covered a region of charge weight in your test where the vertical and/or grouping was optimal, even though it didn't show up as a flat spot on the velocity curve. It sounds as though you're more concerned with producing a load that groups well, even if not quite at the level of BR precision. So using vertical impact (ladder) or the center point of a group may be a more useful approach to optimize your charge weight. Using either one of these approaches, you can still monitor velocity to assure the load exhibits minimal ES/SD within the charge weight range associated with the most consistent vertical and/or grouping.

BTW - 8208 XBR is a fine powder for .223 Rem...I'd be surprised if you couldn't get good results with it. H322, Benchmark, or even H4895, might be alternatives if you do find the 8208 unsatisfactory.

 

[earlcurtis67]

By using the velocity ladder i was hoping to at least narrow down a charge weight for an OCW, I assumed .3 grains would be narrow enough. I think I’ll try loading at .2 grains and put some more effort in brass prep then try again. I’m curious now to see where this goes. Thank you for the assistance. E