OCW Test (30-06, H4350, 165 Sierra Gameking)

[richardca99]

I decided to give the OCW test a try with my .30-06, and I was hoping some of you might help interpret the results. If you're not a fan of this approach, I'd also be interested in hearing your thoughts.

H4350 was the powder, and the 165 Sierra Gameking was the bullet. If you look at the first picture, I loaded from 56.9 to 59.0 in 0.3 grain increments. Hodgdon lists 59.0 as their book max with this bullet (49,400 CUP), while Sierra (inexplicably) lists max as 54.1. I can't find another load book that even comes close to that absurdly low number, so I went with the powder manufacturer's max charge. I had no pressure signs whatsoever.

Looking at the results, it appears to me that there's a range from 57.2 - 57.8 where things are very consistent, and I saw very, very little deviation in velocities across the chrono with these three charges. The POI of the three groups is within 1/8 - 1/4" of one another, which would equate to clustering in a standard ladder test.

I'm inclined to call 57.5 the OCW and experiment with seating depth. Here's a zoomed photo of the three groups in question:

Thoughts, criticisms, or does anyone interpret the groups any differently? This is my first OCW test.

 

[Red River]

My .30-06 load is 57 grs. of H4350 with the 165 gr. GameKing bullet. That gave the best groups in my rifle so your analysis seems right. I didn't do the OCW test...just worked up to the 57 gr. load as it is one of the "go to" loads for the .30-06 that most rifles seem to like. I may have to push the load a bit higher after seeing that 57.8 gr. load, but velocities are already around 2830, so I figured it was good enough. Using some old stock IMR 4350 I drop a grain lower.

 

[richardca99]

What is your seating depth with that load? I'm at 2.630" (measured to the ogive). I think I'm going to move down to 2.615" and up to 2.645" in 0.005" increments and see what happens to accuracy -- holding the charge constant at 2.630".

 

[Red River]

I don't have the right tool to measure from the ogive, so I seat them to chamber easily in two rifles. The brass is simple Winchester full length resized. I recently bought an S-die so I can tinker with neck tension. The rifles are hunting rifles, a pre-64 Win. 70 and a Classic Model 70 bedded in a McMillan stock.

 

[richardca99]

This is Remington brass and Fed 210 primers, and the rifle is a Cooper 52, also a hunting rifle. Have you been happy with the 165 Gameking in the woods? Would you hunt elk with that bullet?

 

[bozo699]

richard,
I have used 165's w/good sucess on game.OCW?

 

[richardca99]

Optimal Charge Weight...it's a variant of the Audette Ladder test developed by a guy named Dan Newberry.

 

[necchi]

57.8 by all means looks to be the better group. The idea is to get the best grouping for the gun then adjust the scope to center.

What kind of pressure signs did you see in the cases as you progressed?

If it where me, at this point, I'd load,, 57.7-57.8-57.9,, go back to the range, and shoot the groups further out. Then start messing with seating depth using the optimum load from the second run.

 

[bozo699]

57.8 by all means looks to be the better group. The idea is to get the best grouping for the gun then adjust the scope to center.

What kind of pressure signs did you see in the cases as you progressed?

If it where me, at this point, I'd load,, 57.7-57.8-57.9,, go back to the range, and shoot the groups further out. Then start messing with seating depth using the optimum load from the second run.

Richard,
I thought for a while before asking what ocw was,I guess I do about the same thing.I use a chronograph,when I stop climing in velocity Im @ my ocw Anyway it looks like its working good for you good luck in the woods this fall.
Wayne.

 

[necchi]

Here it is;
http://www.optimalchargeweight.embarqspace.com/#

actually makes sence, I thought I'd try it myself, I've got some 165's to work up soon also. I've been useing the Audette with success, but never too old to learn. ;D