308 v 7.62 case capacities

[wascal]

Being new to reloading I've spent a fair bit of time researching on the net

 

One of the often quoted facts was 7.62 military brass is thicker , the case capacity is lower so watch for overpressure !

 

being bored tonight I decided check this out.

 

Using brass fired through the same gun resized , trimmed and primed identically, I measured the capacity of 3 types of cases averaged 20 times

The result were

 

Hornady match 308 - 54.24 grn

GGG 7.62 - 53.47 grn

PPU 308 52.86 grn

 

I know this is not an exhaustive test but seems to confirm my suspicion that the primers on my PPU brass were just starting to show "signs" when everything else looked fine.

 

 

[rem708]

I think the above statement is true. If you compare companies which produce military and commercial brass (generally USA based) such as Winchester or Federal there is a difference in cases.

 

I found if you started to push into the area of high pressure - flattening of primers, military brass, headstamped "WW" for instance, would NOT easily rechamber after firing. This then required a slight full length resize. On the other hand brass stamped "Winchester" would rechamber just fine and only need a neck resize. I have always put this down to military brass being thicker and softer - hence less spring back after firing.

 

I have never mixed military and commercial to do a comparison by charge so have never been worried by case volume.

 

Comparing different manufactures may not be a valid comparison but a good piece of research.

[wascal]

 

I have never mixed military and commercial to do a comparison by charge so have never been worried by case volume.

 

 

I have now acquired enough cases to batch by type so this won't be a problem Now.

[figgy]

I watched a online video on this not long ago about how interchangeable the brass was. Not very was the conclusion for .308 recipe's use .308 brass. If you want to 7.62 bras work a load up as case volume is different and over pressure was biggest issue.

[Harnser]

The best all round load that I loaded for .308 was 45 grains of vit 140 with 150 grain bullet . I have shot all British deer species with this load and it never let me down ,ever . A very hard hitting and accurate round travelling at about 2800 ft per second . When I gave up stalking I gave a friend of mine a couple of hundred rounds of this ammo and he said that it was the most accurate ammo that he had ever shot . He shot a big red stag at 150 yards and killed it on the spot .

 

Harnser

Edited April 16, 2016 by Harnser

[Vince Green]

Harnser is absolutely right. There is no reason to be using loads where overpressure might be an issue. If you are target shooting most people actually download slightly to save on cost and shooter fatigue unless they are shooting at ranges over 1000yds

 

45grn Vhit 140 with a 145-150grn bullet is the 'old faithful' load for .308/7.62 used by practically everybody I have discussed it with. Of course we have all tried other powders but nothing betters it. 40grns with a 168grn bullet is equally as good and a bit cheaper.

 

for 200yds we use 16grns of Alliant 2400 and it is very accurate and very cheap.

Edited April 18, 2016 by Vince Green