Load Development

[19818119]

I've noticed there are a number of different Load Development methods in use. I'm interested in what is recommended and why. I've used a Ladder test before, as well as simply trying some recommended loads and am just starting out trying the OCW method.

Opinions appreciated.
Rath

 

[Mag 300]

Re: Load Development

there are a lot of threads, I have tried the ladder test to then go to the OCW test . sometimes it gets to the point of just trying loads. to date I have found them effective in narrwoing down the spread in the powder for each bullet but need a day at the range to finalize it .
just bought a chrono to try and see what shoots the best with
the best repeatability
Bill

 

[Michael]

Re: Load Development

Take your loading gear and chrono to the range. You can have a finalized load in an hour.

 

[myerfire]

Re: Load Development

I really like the OCW method. I expend less components with this method.
myerfire

 

[308sako]

Re: Load Development

Deleted in protest!

 

[maccrazy2]

Re: Load Development

What is the ocw method? I did a search but got a million results.

 

[Witch_Doctor]

Re: Load Development

Short version; start with begining load, move up in .3gr increments until neccessary. The more loads the better, I usually will use 10 loads increased by .3gr consistanting of 3 shot groups. Shoot said rounds in a round robin fashion. Once you have put 3 rounds into each target, you will see three loads that are consecutive and have very similar POI. Take the middle load as your OCW, then play with OAL.

Example: my last OCW test started at 41.1gr of Varget and went through 43.7gr. The result was 42.8gr, 43.1gr, and 43.4gr were all in the same POI, eerily similar. By using the round robin method you take a lot of variables out of the equation. By choosing the middle load you get a bit of leeway with the load; ie change of brass, etc.



Click here

 

[mattkarstetter]

Re: Load Development

so are you trying to match the speed. my question is if my 308 shoots a load very well with varget, should it shoot well with a charge of rl 15 that matched the velocity.

or does the different acceleration of varget and rl 15 make it so that the bullet may not fly as well?

I hope this question makes sense.

i forgot to mention that i would be sure to stay within pressure limits

 

[mattkarstetter]

Re: Load Development

i read dan newberrys article from above and am curious if the initial shock wave is consitent for different powders.

 

[Witch_Doctor]

Re: Load Development

With each powder having different characteristics, you would need to chrono the loads to see if MV is similar. Does 44gr of Varget give you the same MV as the same load of 4895? With the OCW you utilize less components in the process. You will also have different OCW's throughout the spectrum of MV.

The idea behind OCW is that if you change up the brass, primer, or your hopper dumps a bit too much or not enough the load will be within the range of consistancy. Say you work up a load with a Winchester brass, BR2 primer, 44gr of Varget, and 175 SMK, and that load is your sweet spot, but you know that .5gr up or down opens up your groups or moves your POI then you have a very narrow window. If that same group maintains that same consistancy with those variances than you widen that margin.

 

[ReaperDriver]

Re: Load Development

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 308sako</div><div class="ubbcode-body">After the recent good fortune I have had with the OCW method it will be a very long time till I use any other method. </div></div>
And see, I had the completely opposite experience with my 1st OCW try. I just don't think I shot enough groups - so maybe I'll try again with more loads.

I think what surprised me was when I did my 5-shot ladder test previously, I could see obvious small groups and groups that opened up a bit larger - but rarely was the total 5-shot group size greater than about 1 to 1.25 MOA. But when I shot my OCW 3-shot groups with 2 min spacing between shots - I had several that had two shots touching and a flyer almost 2-3 MOA apart.

 

[magyarbetyar]

Re: Load Development

My take on the testing is this. Using the Ladder method gets you in the ballpark as far as powder charge. After that I switch to the OCW method and work up a few 5 round batches and go with what works best.

 

[gnfiter3]

Re: Load Development

Check the thread on Underderstanding OCW. The information here is going in the same direction as the one I started. I like magyarbetyers idea, with a modification.

My 40X shoots a five shot ragged hole with 43.0 grs. of IMR 4064.(slightly vertical) I assumed the vertical track was my breathing.

So I'm going to try the OCW with: 42.4, 42.7, 43.0, 43.3, and 43.6. It has been suggested, more than once. that for 168 HPBT's 43.5 is the sh**. I was so happy with the results of the 43.0 group, I went back to shooting my AR-15. My AR-10 likes 41.5 of IMR 4064, so that will be my midpoint for that one.

OCW seems to take into consideration, factors not addressed by the ladder, but newbie as I am to the process, I just keep reading here, and making better decisions.

It's like going to school and loving the classes.

 

[DaveV]

Re: Load Development

Keep in mind that with the OCW method you are not looking for tight groups as much as you are looking for a trend line. If you start low enough and finish high enough, you will clearly see a scatter group somewhere near the bottom and another scatter group somewhere near the top. Along the way, you may see some very tight groups but, initially, this is not the goal. As you locate a resilient load between the scatter groups, you then work on your seating depth. This will dramatically close up your groups. You then know that you have an accurate load that will withstand differing variable (ambient temps, case capacities, powder lot differences, etc.)

As to the shock wave question, Chris Long seems to prove that the shock wave is consistent in relationship to powder, however, the velocity changes from powder to powder will interact with the shock wave with different results. Remember that the shock wave is traveling up and down the barrel 5 to 6 times before the bullet exits.