Federal .308 brass question

[mcgiiver]

I scrounged some .308 brass from the range, to add to my collection. I was about to reload some and noticed my old brass was headstamped FC .308 Win. The found brass is headstamped FC 14. Other than the crimped in primers on the FC 14, are there any differences I should know about? I am thinking differences like the .223 vs 5.56mm and Lake City brass issues.

 

[rcmodel]

Just weigh the two cases.

If it weighs the same, it is the same.
If it doesn't, it isn't.

rc

 

[Rule3]

One is probably Commercial the other (14) is military. There may be slight differences as mentioned in weight, but once you size and reload there isn't much. The whole debate like 223/556 if one is thicker or case capacity and all that may or may not apply. You would have to do an exact water volume test to be sure of the inside capacity. Is it worth all this. I don't think so, some might.

I just load and shoot.

 

[mcgiiver]

I tried some experiments based on your suggestions.

I weighed five groups of 3 shells each on the scale at same time. Here is what I got.
FC 14 headstamps 526.5 grains for 3 shells, 525.8, 527.2, 526.1, 527.1

FC .308 Win Headstamp, 488.2, 508.8, 490.3, 525.6, 525.0

So I am thinking trim length is affecting my weights. Then I chose, three shells from each headstamp group, with the exact same length. and get

FC 14, 527.1 grains for three shells
FC .308 Win, 507.9 grains " " "

The three conclusions I get are:
The two different headstamped shells are not the same.
The FC 14 ones are heavier, therefore thicker, therefore less capacity.
The FC 14 ones are very consistent in terms of weight.

I tried to fill one shell with water and poured it into the other to compare capacity, and then swap the order. This method was way to hokey to yield any good results.

 

[rcmodel]

If you have any ball powder, do it with that.

Stick type won't give nearly as consistent fills.

rc

 

[Reloadron]

Were the cases run through a full length sizing die? Generally you take the brass and full length size it, then trim them and then weigh them. Some will argue that a fired case should not be sized and will give better volume indications. I never saw much difference. You should have no problem filling the cases with water. I just place a case on the scale using less than a drop of candle wax in the primer cup. Weigh the empty case, then fill the case with water. A meat injector works well for no mess. Adding a little dish washing liquid should help the water "lay flat" in the case necks. "A Little" defined as a drop in a large syringe of water. Subtract the empty case weight from the water filled case weight. On average the mil brass is 54 grains of water and the commercial is 56 grains of water. However, that is not always the case and mil brass will not always be the lower number. Really doesn't matter because you want consistency.

When I load I want all my cases to be the same, I really don't care if they are 52 or 54 or 56 as long as I get uniformity. If you are just loading plinking ammunition even that is not a big factor. Anyway, for future reference, the water weight method is likely the best way to determine case volume. That combined with RC's advice.

Ron

 

[mcgiiver]

Thanks for the great advice.

 

[farmerboy78]

The fc14 is very consistent for you! And yes the thickness difference can matter... I too pick up range brass and have about 4 different headstamps... my charge that I use with my lapua brass will over pressure LC brass and make it difficult to extract so I have to downsize my varget load if I use LC... anymore I use the LC for subsonic loads and use the lapua for range work...