Green788 - I think I'm getting closer to catching on to the OCW thing

[royinidaho]

Green788 - I think I\'m getting closer to catching on to the OCW thing

Green,

I think I have been way too technical/anal regarding my approach. So here's what I did:

Had enough experience with the rifle from doing a ladder test which showed me that all the "books" except Hogdgon's was way off w/4831 and the 243 Win.

Selected 3 powder weights 0.2gr between them, towards the high end of the "book".

Shot them in the round robin fashion.

Studied the results and determined that halfway between the mid and upper powder weight would be best. Chrono velocities showed a good pattern around a certain velocity. The middle powder weight corrected what was wrong withe the lower powder weight's group. The highest velocity with the upper powder weight was definitely a flyer. The lower upper powder weight velocities grouped with the mid powder weight velocities. Thus the final selection of a powder weight half way between the mid and upper test loads.

I picked the load mentioned above and fired three shots. Looked good. Seated a the bullets a schosh deeper and tried that. Things looked better, in fact good enough.

Then I figured (this is a new concept for this old geezer) that this OCW load should handle reasonable variances in temperature and powder and brass. So I loaded 5 with the new seating depth, OCW powder weight and mixed brass, 3 W-W (lighter) and R-P (heavier). Result was about a 1 inch group at 200 yds. Velocities, as expected, were higher w/R-P brass but those shots did not excessively influence the group size.

Is this the right kind of thinkin' or am I like I was in high school when I caught on to alg I half way through alg II then it 'all' came togther.....

Neverthless I liked the results. My son-in-law will too. It's his rifle.

 

[green 788]

Re: Green788 - I think I\'m getting closer to catching on to the OCW th

"So I loaded 5 with the new seating depth, OCW powder weight and mixed brass, 3 W-W (lighter) and R-P (heavier). Result was about a 1 inch group at 200 yds. Velocities, as expected, were higher w/R-P brass but those shots did not excessively influence the group size."

That's pretty much it. /ubbthreads/images/graemlins/smile.gif It sound like you found the OCW, and you found it by searching near the top of Hodgdon's powder charge range. That generally works--and believe it or not, many of Hodgdon's maximums turn out to be OCW load... I don't know why this is, but it seems to be the case more often than not.

I did an OCW "acid test" using some various brass cases for the .243 win. (It's important to note that I had worked up to the particular powder charge with each of the brass cases prior to this test). Here are those results...

I've also shot sub MOA at 300 yards with the 57.5 grain charge of IMR 4350 behind Sierra's 165 grain Gameking in a 30-06--using five different brass cases and/or primers.

A good load will allow moderate pressure changes and it will still perform well.

Thanks for the post Roy. /ubbthreads/images/graemlins/smile.gif

Dan

 

[royinidaho]

Re: Green788 - I think I\'m getting closer to catching on to the OCW th

Well I'll be dad-gumed!

Let's see, that was 3+3+3+5 for 14 total shots. Good deal...

I'm learning.....Slowly.......