OCW Load Powder Change Using Chronograph

[Spin Drift]

I have a good load worked up for my 308 using a powder which has become impossible to find here. I used the OCW method for load development. I have a magnetospeed chronograph. Can I just work back up to this same velocity using the same bullet but with a different powder and still be in the same accuracy node without group testing and finding the nodes all over again?

Has anyone here tested OCW with more than one powder but everything else the same like brass, bullet, primer, firearm?

 

[twarr1]

Every powder has a different profile and pressure characteristics which will effect nodes.
We generally arrange powders by type and relative burn rate. But there are many other factors that affect performance like brisance, specific heat, etc. Even if muzzle velocity is identical between 2 powders, the internal ballistics will be different.
My 2¢

 

[sparkyv]

This ^^^

 

[AJC1]

Your previous velocity give you a good point to start.... load around that previous velocity and find where the new powder is happy.

 

[Nature Boy]

Short answer is no. The speed of different powders is not a common denominator when it comes to finding the accuracy node

 

[Spin Drift]

@Nature Boy
I'm not talking about the burn speeds of the powders. I'm talking about loading to the same bullet velocity with a different powder (if safely attainable) and hoping to still be in the OCW node. Maybe you knew that but just thought I should make sure we are on the same page.

 

[lordpaxman]

Has anyone here tested OCW with more than one powder but everything else the same like brass, bullet, primer, firearm?

This is the OP’s question. I’d love to know if anyone else has actually done this? I tried it with a 30-06 load, the velocity node I picked was an accuracy node as well, or at least for my shooting. Perhaps I got lucky?

 

[Hugger-4641]

I've had hit and miss. It worked when I reverse engineered the Hornady Precision hunter in my 700cdl sf 30-06. It happened to be in an accuracy node and I matched the velocity with Superformance and got about the same sub moa group. It did not work with Stabal 6.5, but I did find a seat depth that did work with Stabal at the same velocity. My Howa 30-06 was a lot more finicky, had to increase the speed a little with Stabal and RL 17 to get the sub moa group.

 

[twarr1]

As @AJC1 commented, starting around the old velocity should get you in the ballpark. Closer than starting from scratch.

 

[Nature Boy]

@Nature Boy
I'm not talking about the burn speeds of the powders. I'm talking about loading to the same bullet velocity with a different powder (if safely attainable) and hoping to still be in the OCW node. Maybe you knew that but just thought I should make sure we are on the same page.

I wasn’t talking about powder burn speed either, I was referring bullet speed.

My comment stands. If velocity was all there was to it, load development would be a piece of cake. It’s not that easy or simple. When you change a component you have to perform another OCW cycle to find the node.

 

[AJC1]

It is a simple as barrel harmonics and timing... if you can measure and match that you will have it made.

 

[Spin Drift]

Well thanks for the insight guys. I will run another ocw test with the different powder. I will make sure I cover the velocity that worked well with the other powder.