OWC help??

[hogginhank]

Just wanted to chime in and say that this forum is packed full of great info. Been checking it out for a while and have really been reading a lot of threads. The OWC and ladder method are new to me. I always thought that when I was working up a load in .3 gr increments for 100 yard groups that I was using the ladder method?? Anyways I do have some questions in figuring out the " nodes" and all the little things that I read about and though I've read a ton about it, I'm a little lost( just a little). I am on my phone so I will have to get on my lap top to post up the pics of my groups so I can get a little help on what groups are what.

I have been reloading for 20 years so I'm not a newbie in general but this is the first time to try loading for a semi-auto gun. I have an AR 223 with a DPMS 20" bull barrel and a 1:9 twist so y'all know what I'm launching lead with. I will get on my lap top and see if I can post up a few groups that I need help with. Thanks in advance for any replies. Hank

 

[Tripwire]

Re: OWC help??

Here's some more reading OCW.........

 

[Early Cuyler]

Re: OWC help??

Here is my understanding of the Ladder and OCW tests. If anyone sees anything wrong, please correct me.

In the ladder test you load up single rounds usually in 1% increments and fire them at 200-300yds using the same point of aim. The variations in powder along with changing barrel harmonics will cause your point of impact to gradually shift vertically. In this process however you will notice groups to naturally develop indicating "nodes". For instance for a 308 you might notice the 43.4, 43.8, and 44.2gr rounds grouped together (vertically). This gives you a range to fine-tune your loads so you can go back and reload enough 43.4, 43.5, 43.6, etc. for group testing. Then you simply pick which load gave you the best group after testing.

The OCW or Optimal Charge Weight test is very similar to the ladder test except you shoot 3-5 shot groups at 100yds using the different charge weights instead. You then measure where the groups' centers to the point of aim on each target. You will notice "nodes" appear based on the point of impact (e.g. 43.4 will hit 2" high at 100yds, 43.6gr - 2.2" high, 43.8gr - 1.9" high). Now you simply locate the node of groups and find the "center" (in this case 43.6gr) and that is your load.

The idea behind the OCW test is that by this method the variations in pressure that will occur due to temperature change, humidity, elevation, inconsistent reloading, etc. is less reflected in group size. For the ladder test you might get great accuracy, but it will be for one temperature, humidity, etc.

One thing you can do to save yourself time and resources for reloading is to use the Ladder Test to identify nodes and then within those node ranges, do an OCW test. This limits how many groups you have to shoot for the OCW test. I've read and heard (real-life) of this being done to great results.

I've done a ladder test before but not an OCW test. I am going to do an OCW test for my .223 AR15 tomorrow only. The reason I'm not doing a Ladder Test is I'm changing my charges by .2gr anyway so I'm not worried about that extra bit of fine tuning (it's not a precision rig..... yet).

 

[hogginhank]

Re: OWC help??

Thanks for that link tripwire. Dans site is where I read all the info about OCW stuff.. That forum has a lot of threads on OCW and ladder testing.. Thanks again. I registered there also

A question for you halcyon?? So I "Can" do the ladder test at 200 yards?? I wasn't sure if I read that it was better done at 300 to 500? I have access to a ranch with a pretty nice 100 yard range with a huge hill(actually it's like a small mountain) as the back stop and I'm thinking that just over 200 will be the most I can get out of that spot without shooting up hill. Thanks for the info..I will be loading up some more .3 gr increments to try out on monday when I get of duty. I only tried 24.7 gr and 25.3 just to get an idea how the R-15 shot with the 60 bullets so I need to load up the 25 and 25.6 gr to round out my results..So far I have 2 Five shot groups at 100 yards that were probably .8 to .9" and had pretty much the same POI so I'm excited to see the POI's of the other groups and compare them..Adios' for now..Hank

 

[Trapshooter12]

Re: OWC help??

When I started chasing loads I did the Ladder test. It is very time consuming because you have to mark every shot you can't just shoot the paper and understand what each round did.

I went to the OCW method and it saves me a lot of time and reloading.
I do it just a bit different. I load ten rounds and shoot them for two five shot groups, this way if I have a hiccup I can rule out the load or try it again. I also do my OCW at 200 yards this way it gives me a better understanding of my groups.

 

[bgweed]

Re: OWC help??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Trapshooter12</div><div class="ubbcode-body">When I started chasing loads I did the Ladder test. It is very time consuming because you have to mark every shot you can't just shoot the paper and understand what each round did.</div></div>

One thing you could do to get around marking every shot is to get a poster board from walmart, put a grid of target dots, and then shoot each successive round at its own target dot. You could draw each POI on a clean target to get a picture of how they rounds compare to each other. A little more work, but at least you dont have to mark each round.

Something to note... if you did what I just described, but you shot 3 rounds at each target... you're basically doing an OCW test.