OCW spreadsheet

[gmelahn]

I have been steadily getting more and more involved in reloading over the past six months and have learned a lot of great information form this website.

In my research I have found two main ways to work up a load, Optimal Charge Weight(OCW) and Ladder. Since I don't have the required 300 yard distance readily available to preform the Ladder I opted for the OCW.

The OCW however required a little more calculations so I decided to make it easier for myself by formatting my own spreadsheet with all the calculations taken care of by the computer. All you have to enter is the max loads from the different sources for your bullet and powder and it does the rest.

- After entering max loads from your various sources the spreadsheet averages them out.

- sighter rounds start a minus 10% from average max then move up by 2%.

- loads start at +2% from #3 sighter then move up in 1% increments.

- All charge weights are rounded to the nearest .01.

- when a charge exceeds the average max load the box turns red.

Please review the spreadsheet, any critiques are appreciated. PM me if you want me to email it to you.

Let me know what you think.

Thanks, G-

 

[azar]

Hmmm, I don't see a spreadsheet...

It's funny, but I recently did the same thing with a few minor differences. It does simplify things doing it that way.

 

[gmelahn]

don't see a spreadsheet???? I poster a screenshot of it. What were your differences?

 

[USSR]

In my research I have found two main ways to work up a load, Optimal Charge Weight(OCW) and Ladder.

In my experience, there are two kinds of people: those that believe in OCW, and those that don't. Count me with the later.

Don

 

[gmelahn]

Since I'm pretty new at this whole reloading thing care to share any knowledge?

 

[azar]

gmelahn,

Nevermind. After I posted I realized it is probably my connection. If it's not hosted at thehighroad.org but instead at some external site (like photobucket, et al) then I won't be able to see it. I'm on a filtered Internet connection right now and the image is likely blocked for me.

 

[WNTFW]

Gmelahn,
I have used the OCW method with good results. It is a variation on the ladder method that tries to fix the ladders downsides. I believe in aspects of it and some aspects I don't buy into. There are some points that I found helpful. Bottom line for me is it is a method - so you are ahead of the game.

What it is for me is a quick way to find a decent load that will work without going through hundreds of components. The load is not necessarily the ultimate load and may need some refinement. It is a good quick path to a solid starting point. Nothing beats sample size in the long run to see which loads shoot better over time. Some guys seem to jump around too much. I'm not smart enough to keep up with all the variables. Sometime conditions are just not conducive to load testing. I've come to realize a lot of load development is decision making. Picking between groups can be hard. Knowing when to quit tweaking and settle on a load is not always easy. And lets face it, we as shooters induce some error into the equation.

Spread sheet is cool. I usually just do mine by straight calculations. Seating depth is not listed. (COL) I usually include my weighing method. "All charges trickled" or "All charges thrown and spot checked". I write the Charge weight & load # on the target as well. That way I verify that I am shooting load 1 (42.8 gr) on target 1. If you lose your paper/laptop battery you still have the targets labeled.

 

[azar]

BTW, now that I'm home I can see the spreadsheet and it looks nice. Sorry for the earlier confusion.

 

[gmelahn]

Thanks for the info, I decided to use the OCW because I don't have a level 300yds to work up a load on. I agree that its a good starting point and I can tinker with the load from there. I'll ad the COL or OAL to the spreadsheet. let me know if you want one.

G-

 

[Kernel]

You should be consistent with your precision and list charges only out to a tenth of a grain. Anything more is just silly. A long string of numbers after the decimal point is meaningless. Stick to SIGNIFICANT digits, it will make your work look neat and more professional. Otherwise, it looks pretty good.

 

[RKRCPA]

Ok, maybe I'm just not as technical as I should be but what is the point of the spreadsheet? What does it demonstrate or prove or... ? Does it provide some useful information?

 

[Tim the student]

Does it provide some useful information?

It has his info for OCW in a handy spreadsheet. I don't know how to explain it differently - not trying to be snarky.

If you are not familiar with OCW, check out this site. It may make more sense then.

 

[gmelahn]

The purpose of the spreadsheet was to make the process a little quicker. Nothing really more. I thought I would post it here to see if anyone wanted it?

 

[WNTFW]

The spreadsheet or any form is good because is standardizes the data and you won't forget something. The spreadsheet can also calculate the charge weight incriments and flag loads exceeding max charge weight.

---------------

"You should be consistent with your precision and list charges only out to a tenth of a grain. Anything more is just silly."

True - You are trying to identify the middle of a "sweet spot" that will tolerate some variance.

----------------
Keep up the good work GMelahn

 

[gmelahn]

Thanks everyone I hope this can make things just a bit easier for people. I have sent out about 30 email to various people and they all seem to like it.

Thanks Guys,

G-

Have a great 4th

 

[gmelahn]

Here is the updated spreadsheet, I changed it to only round to the .1 and added a place to input OAL. Thanks for the input.

G-

 

[MCMXI]

In my experience, there are two kinds of people: those that believe in OCW, and those that don't. Count me with the later.

Don, I have a lot of respect for you as is evident from our personal correspondence and posts on THR. However, I respectfully count myself with the former i.e. I DO believe in the OCW method.


gmelahn, are you making up five rounds for each sighter # and load # listed? You have (load 3) shown in the Charge Weight box which makes your method look more like the ladder method. Also, what is "Adjusted Charge Weight"?

 

[Walkalong]

Nothing beats on target results.

As you work up the load there will be "sweet spots". Pick one. Tweak it to see if it can get better.

 

[gmelahn]

I put a place for adjusted charge weight just incase someone wanted to change the calculated weight they had a place to write it in.

I believe as per the OCW method that you load one round for each sighter and three for each graduated load.

BTW this is by no means "my method" I am still learning to reload and I thought this might help a few with the OCW process, thats all. I wish I had 300yrds readily available because I would like to try the ladder as well.

Any help from the more experienced reloaders is always welcome.

Thank you Sir

Respectfully,

G-

 

[USSR]

Hey, if you believe in it and it works for you, great. But I am able to find sweet spots in the velocity range I want without the hassle.

Don

 

[gmelahn]

Don,

Whats your method? Like I have said I'm pretty new at this and OCW was one of the methods I could use at 100yrds, any suggestions?

 

[USSR]

My starting point is selecting a suitable powder/bullet combo, and determining how much powder I need to reach a certain velocity range that is predetermined to be safe and doable. This starts with loading cartridges and varying the charge weight by .5 grain, and then running them over a chronograph. The reason I do this is, I find no satisfaction in finding an accurate load that is hundreds of fps slower than what the cartridge with that particular bullet is capable of. Of course, I start by shooting the lighter loads over the chronograph, and I stop when I reach a predetermined velocity. For example, for a .308 Winchester with a 175-178gr bullet, I am looking for a load in the 2700-2750fps range, so I will stop when I get velocity readings near 2750fps. This often entails having to break down cartridges with too much powder in them, so be sure to have a tool to pull bullets. Once I have an idea as to how much velocity "X" amount of powder yields, then I play around with 5 cartridge loads that vary by .3 grains lighter of heavier, yet that remain in the velocity range I am looking for. These 5 cartridge groups are shot over the chronograph, except now I am looking for low SD and ES numbers, as well as accuracy on target. Unlike many people, my COAL is fixed so that my bullets ogive is .010-.012" off the leade for cartridges designed to be magazine fed. If I am making competition cartridges that are to be single loaded, I usually load them .020" into the leade with light neck tension. Whether you fix the charge weight and play with the COAL or fix the COAL and vary the charge weight, you are still searching for the combination of the two that produces accuracy and low ES and SD numbers. There are many ways to skin a cat, that's just the way I do it.

Don

 

[gmelahn]

Thanks for the information, I have not bought a chrono yet looks like that may be my next purchase.

Thanks again

 

[BigBob3006]

gmelahn,

I've been loading for over fifty years, and I still make mistakes. I just don't make the same one twice. With all those years of firing test loads I just wish I understood all I have been exposed to. One thing I am very sure of is the OCW method doesn't come close to giving me the information I want. And it doesn't give me the most accurate combination of components in my particular rifle. One thing I have learned time and time again, is that each rifle is an individual. A load that has worked in one rifle may or may not work in another rifle of the same make and model. The ladder method is the only method I have found that does work. A chronograph is almost an necessity. The greatest eye opener I've come across in reloading is the actual velocities factory ammo delivers. I think the .270 Win. was the biggest disappointment. Bullets come in a close second place as to what a barrel does or doesn't like. Primers are also in that list. At one time I'd buy a pack of all the primers I could find and run test loads wit each primers. I eventually stop doing this when I discovered that CCI always seemed to furnish the greatest edge of accuracy. I bought Sierra bullets. But either Sierra lost their edge or other others have improved their accuracy. I used the Nosler Partition for several years until Hornady brought out their Inter Bond. It gives the improved ballistic with greater aerodynamics and terminal performance and switched everything I loaded for to that bullet. I had to work up new loads for all of them. It took me almost a year. Everything that is, except the 55gr .224 varmint bullet in my .22/250. That still likes the Nosler. I hope that this is of some help.

 

[Dave P]

In my mind, OCW and the Ladder (from Creighton Audette) are very similar. And I firmly believe in them. I have had very good results on bolt guns, by just shooting 10 rounds (308, .3 grain step size).

Quick, fast, and repeatable. A lot easier than shoot-and-pray, which burns up a lot of barrel life - ask me how I know!

200 yard range is what I use.