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?

 

[varmint slayer]

Most people do them farther than 100 yards. I rarely see one inside 200 for that matter. Lots go out to 4,5, or 600 yards pending caliber.

 

[Recreational Shooter WA]

Dan Newberry addresses this on his website.

OCW Overview - Dan Newberry's OCW Load Development System

 

[steve123]

OCW at 100Y

Ladder at 300-400Y in .1 grain increments will tell you everything you need to know in 20 shots or less. You must pick a calm day and let the barrel cool after each shot so results are uniform.

The last one I did with my AR in 223 with 70 gr vld and H-4895 netted a load in 12 shots showing 3 consecutive shots into 1.2" wide by .6" tall.

 

[SWThomas]

OCW at 100Y

Ladder at 300-400Y in .1 grain increments will tell you everything you need to know in 20 shots or less. You must pick a calm day and let the barrel cool after each shot so results are uniform.

The last one I did with my AR in 223 with 70 gr vld and H-4895 netted a load in 12 shots showing 3 consecutive shots into 1.2" wide by .6" tall.

So if you did a ladder in .1 grain increments and only fired 12 shots, you found "the load" in only 1.2 grains?

 

[waveslayer]

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?

I do the initial at 100 and once I narrow down my node I move out to 2 to 3 hundred yards. Then I do a seat depth test...

 

[Steve Williams]

Dan Newberry addresses this on his website.

OCW Overview - Dan Newberry's OCW Load Development System

I recently had to switch to a different load (.308 LC LR 178 A-Max & 4064), my Savage (tight chamber) was over pressure
with the 185 Bergers. Not to mention a case head separation. No more .308 Win Mag Loads for me...

So I narrowed it down to a charge, then Dan told me to run it out to 900, and check for vertical dispersion.
So we did, and the vertical was very consistent at that distance.

I jokingly said to him "who does an OCW test @ 900", his reply, "we just did".

There is merit to testing/confirming at longer ranges (if you can), as the deviations show up more readily.

 

[steve123]

So if you did a ladder in .1 grain increments and only fired 12 shots, you found "the load" in only 1.2 grains?

Absolutely correct concerning the powder charge!

Next trip out I used the middle charge of those 3 consecutive shots. Here's a pic of the steel. Top 3 shots were 285Y - far left was cold bore, middle three at 400Y, last four at 589Y. It was very windy thus the wide horizontal. I was aiming 4-5 feet left to hit that steel at 589Y. Note how tight the vertical is though.

Yes I could have stopped with load development right then but I experimented with seating depth with 3 more 5 shot groups at different depths at 100Y on the next outing. 2 of those three groups had 4 shots touching but one group was .4" with 4 into the high .1's. The AR only has a 15" barrel and I will rarely be shooting it at 600Y so I'm done now.



I also did this same method with my 6x47L barrel. The upper node was 5 consecutive shots into .9" at 400Y. I picked the middle charge and did not change the seating depth. Then went on to win more than a few matches with that load.

 

[Recreational Shooter WA]

I recently had to switch to a different load (.308 LC LR 178 A-Max & 4064), my Savage (tight chamber) was over pressure
with the 185 Bergers. Not to mention a case head separation. No more .308 Win Mag Loads for me...

So I narrowed it down to a charge, then Dan told me to run it out to 900, and check for vertical dispersion.
So we did, and the vertical was very consistent at that distance.

I jokingly said to him "who does an OCW test @ 900", his reply, "we just did".

There is merit to testing/confirming at longer ranges (if you can), as the deviations show up more readily.

But the initial testing was done at 100, correct? Then confirmed at longer range?

 

[Steve Williams]

But the initial testing was done at 100, correct? Then confirmed at longer range?

I had previously done some testing at the next higher node, but they still showed pressure signs (this was done @ 100).
I then loaded 3% down to the next node for this trip, fired a few @ 100 to re-zero, and then on
to 900.

Dan has an extensive mental database of charge weights/calibers, so get in touch with him if you can.

 

[SWThomas]

Thanks for the info gents! I think I'll shoot an OCW first and then do a ladder to confirm and see what my results tell me.

 

[waveslayer]

Thanks for the info gents! I think I'll shoot an OCW first and then do a ladder to confirm and see what my results tell me.

Do the OCW and the move out to at least 300 and do another Ocw test.

 

[Recreational Shooter WA]

Dan has an extensive mental database of charge weights/calibers, so get in touch with him if you can.

Agreed, he's the man!