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View Full Version : Little esoteric, but I've been thinking



308sako
08-30-20, 19:54
Most specifically regarding the .308 Winchester, well to start. You see I have cases which vary in weight/volume and of course brand as well it is suspected from 153 grains to 181 grains, So assuming a node is found at a particular charge or velocity (barrel time:) Does in reality the weight/volume have a subtle affect on the burning rate of the powder charge? If so I am thinking that there is also a node of sorts for a particular powder as to it's most consistent burn rate.

Flog away as I am curious as to what others might postulate regarding this miniscule (?) effect.

PracticalRifleman
08-30-20, 20:37
If you are thinking one load will be good across all the stamps, you rarely know until you try. I seriously doubt it will with reasonable accuracy unless you sort by stamp. Then maybe but it will be sub-optimal I’m each. And odds are mixed stamps won’t group that well.

You see, you’ll get velocity deviation and impact shifts due to not only pressure variation, but differences in neck tension, case hardening, and so on.

So set expectations accordingly. Maybe you can make it work if 1.5-2 MOA ammo at 100 works. Yeah there may be unexpected flyers at 500 that make you miss the target entirely. But if that is a success, rock on.


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308sako
08-31-20, 00:37
No I sort brass by weight and lot so that would not enter into this. That said I absolutely concur with your response.

markm
08-31-20, 08:28
.308 unlike most .223/5.56 definitely requires sorting. My dies are set up for the thicker neck brass like MEN, FC, LC LR, Lapua, etc.

Everything else gets pitched into the scrap bucket. (Win, Hornady, etc)

Bimmer
09-01-20, 11:09
Does in reality the weight/volume have a subtle effect on the burning rate of the powder charge?


No. As I understand it, it's NOT "subtle." It's a BFD.

I haven't started loading .308 yet, but I'm already sorting brass by headstamp...

Nightvisionary
09-02-20, 09:24
I guess it all depends what your expectations are. About half the 308 brass I load are range pick ups. Just about every head stamp under the sun. I loaded several hundred using MK-316 clone load data. I am getting about 1 MOA through a Savage 10FP. I used to weigh and sort brass and 175 SMK bullets. For me it's just not worth the effort. If I ever get into match shooting that might change.

Bimmer
09-03-20, 14:50
I am getting about 1 MOA through a Savage 10FP. I used to weigh and sort brass and 175 SMK bullets. For me it's just not worth the effort.

You're getting 1moa using random brass? I'm impressed...

I figured I would start with one headstamp to eliminate that variable (I have some Lapua!), but I wasn't going to bother sorting bullets or brass by weight.

Nightvisionary
09-03-20, 15:10
You're getting 1moa using random brass? I'm impressed...

I figured I would start with one headstamp to eliminate that variable (I have some Lapua!), but I wasn't going to bother sorting bullets or brass by weight.

I was very surprised when I zeroed my Savage FP to the new load last week as I loaded it for my AR-10 and FAL and the bullets were pulls albeit with no observable pull marks. I would have been happy with 2.5-3 MOA.

ubet
09-07-20, 12:20
If you’re running it as blasting ammo why the fvck cares? If you’re running good ammo and want precision though you should be running one headstamp, same powder, primer, and bullet.


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