Anyone do OCW test at further than 100 yards?

[SWThomas]

I'm going to conduct an OCW test this weekend for my new bolt rifle. I was wondering if there would be any advantage to doing it at say 200 or 300 yards? It seems like you could get a better handle on the longer range accuracy of a load and also allow the bullet some more distance to stabilize.

What say you?

 

[amlevin]

I've pretty much stopped doing load development at 100 yards. I use 200 yards as a minimum and 300 yards if I can.

It's easier to sort out things like vertical spread when you shoot the longer distances. With my rifle, a group of 3/4"-1" at 300 yards is often a "bug-hole" at 100 yards. I might have just accepted the "bug-hole load" from a 100 yard workup but at the longer distances I'll fine tune it more.

 

[BradY]

I have done it at 1000yds BUT you need very very still conditions to do it. Any slight puffs of breeze or boiling mirage and its a waste of time. I also had an electronic target system to do it with.

300yds is fine, Im liking 100yds as its easier to find places to do that. And its fairly easy to see when you have a load in tune. It just starts bugholing and if your using it at long range if you have a good ES to go with it, then generally thats quite good- as you will note from Erik Cortinas thread on load development.

On occasion at 100yds with something like a 6BR, dasher etc I do find 100yds a little harder to read out- as generally they go into a nice cluster anyway.

 

[Alex Wheeler]

I don't use OCW but I do shoot groups incrementally at 2-300 yards. You will not always see what your looking for in the OCW method. My best barrel at 200 yards for example. Every charge printed slightly higher than the previous group. No flat spot at all. By picking the flattest group and tuning it from there at 1k, that barrel will agg. 4" or better.

 

[Jeffvn]

I do velocity testing @ 100 yards. For actual load testing I use either 300, 400, or 500 meters (the furthest that conditions will allow). The results will start to show through significantly more clearly at distances beyond 300 yards.

JEffvn

 

[Warren Dean]

I'm going to conduct an OCW test this weekend for my new bolt rifle. I was wondering if there would be any advantage to doing it at say 200 or 300 yards? It seems like you could get a better handle on the longer range accuracy of a load and also allow the bullet some more distance to stabilize.

What say you?

The OCW procedure isn't about accuracy. It's about consistency.

It's about finding a load that your rifle shoots very close to the same point of impact in a +/- .3 gr. charge weight range. Getting the harmonics right is the first step.

When you find that load, then you start tuning for precision with seating depth adjustments at longer ranges.

Tune for precision, adjust the scope for accuracy.

 

[amlevin]

I'm going to conduct an OCW test this weekend for my new bolt rifle. I was wondering if there would be any advantage to doing it at say 200 or 300 yards? It seems like you could get a better handle on the longer range accuracy of a load and also allow the bullet some more distance to stabilize.

What say you?

The OCW procedure isn't about accuracy.

It's about finding a load that your rifle shoots to very close to the same point of impact in a +/- .3 gr. charge weight range. Getting the harmonics right is the first step.

When you find that load, then you start tuning for precision with seating depth adjustments at longer ranges.

Agreed. I just believe that you can get better results if you use a range longer than "point blank".

 

[SWThomas]

Thanks for the input fellas. I think I'll go with an OCW at 300 yards and see what I come up with. I'll post up the results.

 

[4xforfun]

"OCW"???

Color me stupid, but I have never herd of it. It sounds by your responces like a "ladder test". Is that what we are talking about??

Tod

 

[Warren Dean]

http://optimalchargeweight.embarqspace.com/

 

[amlevin]

"OCW"???

Color me stupid, but I have never herd of it. It sounds by your responces like a "ladder test". Is that what we are talking about??

Tod

In a way it is. Rather than one shot per powder charge, looking for nodes, OCW uses three shots per load to reveal the nodes.

For some the Audette Ladder test is difficult to decipher as it uses a single aim point. OCW uses a different aim point for each powder charge so it's easier to work with for many.

Even those who use the Audette Ladder then transition to a form of OCW for developing loads in the "nodes".

 

[M14AMU]

I do a 10X test! Get a zero from 200 yards and then go to 600 & 1000 yards. If it shoots 10s and Xs there....that's all the test I need!

 

[nhm16]

Erik Cortina's method for long range load development is a variation on the same theme.

 

[SWThomas]

In y'alls experience, is it important to round robin an OCW or is it just as effective to shoot groups with each charge before moving on to the next?

 

[Warren Dean]

Round robin is what the developer of the technique says to do. So I just do it and have had great success with it over the years.

 

[amlevin]

In y'alls experience, is it important to round robin an OCW or is it just as effective to shoot groups with each charge before moving on to the next?

Round robin shooting helps make each group subject to the fewest variables like barrel state of fouling and heat.

When I want to take the time I shoot one round from each charge weight at a different target. I'll then run a couple dry patches through the bore and let the barrel cool while I have a soda or cup of coffee.

Shoot the second round from each charge weight and repeat the clean/cool/drink process.

This way every round in each group has been fired under the same (or close to) conditions and the only variable is due to the actual barrrel harmonics, etc. Not with varying levels of fouling and varying levels of barrel heat.

Only way you could get closer (IMHO) is to "Patch" after every round and let the barrel cool to a given (and measured) temperature before firing the next round. That could turn a 25 round OCW test into a really long project and also bring some different "atmospheric" conditions into play.