Ooops - Sorry - I thought I WAS in the "My New Best Friend" posting. I guess that confusion comes easily at my age (and IQ)

At least this part of the posting fits this forum:

I just came across a note at the end of the section for the K-31 in the Sierra reloading manual:

" In developing the following data, we used five different Schmidt-Rubin rifles. Considerable difference in bore diameter caused wide variations in pressure. Therefore, we strongly urge the 7.5x55mm handloaders to slug the rifle's bore and use extreme caution in working up loads."

No that was probably my fault, I get carried away, and I apologize for steppin on toes. Thanks for the heads up on the rifle bores 44Marty.

Suz

Vince, I'm with you........ 43.5gr should be the OCW load !!! ( I think I got the tops of all the targets right.....did you ???)

One must remember that while studying the targets we are not looking for the best group. We are looking for what groups impacted the same area of the target.
Typically the groups will start high left and work down to the right with 3 groups impacting in the same general area.
If you test the entire min. to max. range you should see 2 OCW loadings. The second will most likely be near max. charge.

chambered221 wrote:

One must remember that while studying the targets we are not looking for the best group. We are looking for what groups impacted the same area of the target.

No sooner than you get back, your in the saddle challenging us. I'll have to think about this some more. I use OCW to help find the sweet spot, but if a few tenths of a grain one way or the other provides tighter groups that remain consistent .....

Slim, This link from Dan Newberry gives a better description and understanding of OCW !!!

optimalchargeweight.em...space.com/

Well...using 43.9gn of Varget as my start load I went .7% either side...and also tried one at 41.5gn of Varget (the load Nosler claim to be their most accurate). Loads were all Varget...43.6gn, 43.9gn and 44.2gn. I also shot 5 shot groups rather than the three shot groups used previously.

To be honest...I am a little disappointed with the results. The conditions on the day were a little different to the initial test day...wind was up and coming from left to right, and the light was also different. I know it sounds like I am making excuses...not so...things were just...different.

Oh well...I have revisited all the posts on here, and taken into account all the suggestions, including Chambered's late entry...and I think that I now have enough data to make a more definitive and objective decision on the load that most suits my rifle.

Before I air that decision I will post the final group of targets for you guys to peruse and comment on.

Cheers, Vince

Last two targets.

The dark art of load developement. "A hijacking"
My history with the 243 cut short,
tried to many powders, to may projectiles (weights and manufacturers)
Primers, cases, OALengths. Days and nights examining charts, loads, targets and listening to expert advice. I believe I wore the barrel out.
But out of it I learnt alot about myself and reloading.
A quick rebarrel to 7/08 (another $$$ lesson).
All problems solved.
Actually I was going to suggest you try 06H, less pressure more velocity?
But then I don't advise putting in to many variables or options.
Pick a bullet, pick a powder and try your best to make it work.
Sometimes it happens, sometimes it don't.

What you say makes a helluva lot of sense Tiks...but I have this thing about making a powder/load work.

I am doing my best to work out a combination whereby I have only one powder on the shelf for all my reloading needs...and it appears that 2208 is the the one. I load 30.30 and .243 Win and it it working well in both, albeit with heavier bullets in the .243, so....I'll just keep plodding along and see where it leads me mate.

As an aside....you freezing your butt off down there mate? I've heard that it is getting below zero in the western suburbs of Sydney.

Cheers, Vince

Vince wrote:

you freezing your butt off down there mate? I've heard that it is getting below zero in the western suburbs of Sydney.

Wow, a good example of polar opposites. The East Coast of the US has been "enjoying" 100+ degree days! Even hotter than down here in Texas.

Back to the post at hand, I've experienced these disappointing days too, mate. Unlike you, I gave up. Sold one rifle and went back to factory loads on the other.

I still like 43.9 (maybe 43.8). I checked the earlier post and didn't see whether you crimp or not. If not, that could help. Also, maybe load up some 43.9 again and try several seating depths. Oh, I remember another load I had that went south like this where I didn't give up. I changed from Remington to Winchester brass, did OCW again, and found a very tight and consistent sweet spot. The type of brass has been the biggest effector of group size for my loads.

Vince, It appears to me that you have some serious vertical stringing occurring, although I still believe 43.5 to be the load.

Part of the problem may be in your choice of target.
Whenever shooting for the smallest group possible one should use a target sized for the crosshair at the distance being shot.
Focusing on the smallest target possible helps shoot small groups by eliminating the unintended issue of not getting the crosshair in the same place each time.

optimalchargeweight.em...space.com/
optimalchargeweight.em...4529817134

Anyone interested in OCW please read these 2 links, I think there is some confusion on what it is and how it works !!!

Please pay particular attention to steps 15, 16, and 17 in the instructions.

Yes it has been frosty down here Vince
Attached is my last OCW test for my 444,
OAL is fixed and to my way of thinking the only variation is powder.
I'm leaning to 49.5 which is half a grain over max but may settle for 49.

Chambered have I got it wrong?

I don't think so. You are lucky enough that your tightest group is also the one that matches the consisent POI.