Which OCW spread for .308

[fear-mn]

About to load up for an OCW test on my .308 bolt gun. Pretty new to it. Ran one OCW test with good success on my AR so far. The max loads for .308 vary widely by publisher. So, which OCW spread would you use??

Using imr 4046 and 178gr hornady a-max out of a 1:10 20 inch bolt gun.

40, 40.8, 41.6 for sighters.
42.4, 42.9, 43.2, 43.7, 44.1, and 44.6 for test loads.

OR

39.6, 40.4, 41.2 for sighters.
42, 42.4, 42.8, 43.2, 43.6, and 44 for test loads.

Not really sure which way to go. Powder and dies are all set up to load 'em up!!

Thanks all!!

 

[Twoboxer]

I don't like 0.5gr increments in 308, IME 44.0gr is about all depending on what case you are using, and FGMM 175gr ammo uses 41.75gr of IMR4064.

So I like your second set to which I would add 41.6gr.

I would probably just make all my sighters/foulers at 41.2gr to get more info on that end of the spectrum.

 

[fear-mn]

I don't like 0.5gr increments in 308, IME 44.0gr is about all depending on what case you are using, and FGMM 175gr ammo uses 41.75gr of IMR4064.

So I like your second set to which I would add 41.6gr.

I would probably just make all my sighters/foulers at 41.2gr to get more info on that end of the spectrum.

This sounds like a solid plan here! I was struggling with the # to subtract from to start the testing, and where to end it given that the published max's varied so widely.

 

[sib1948]

My 308 loads for IMR 4064 are 42.8 gr. for 168 & 175 gr. SMK and 43.9 gr. for 185 gr. Berger VDLs. Didn't find that primers or seating depth made significant difference. New Lapua and once fired Win brass were the same. COAL 2.86". No pressures signs and get 8-10 or more reloads before primer pockets loosen. Good luck.

 

[fear-mn]

My 308 loads for IMR 4064 are 42.8 gr. for 168 & 175 gr. SMK and 43.9 gr. for 185 gr. Berger VDLs. Didn't find that primers or seating depth made significant difference. New Lapua and once fired Win brass were the same. COAL 2.86". No pressures signs and get 8-10 or more reloads before primer pockets loosen. Good luck.

That is some really good mileage out of your brass!! I've only just begun so the most I've gotten is 2 firings on some 223 reloads so far.