.308 case volume

[plant.one]

with all the recent discussion on .308 brass, and whats the 'best' brass, etc... i was wondering if anyone has the case volume (in ml) differences on the various common 308 brass on the market

FGGM
LC
Lapua
Winchester
Hornady Match
Remington

etc...

Does anyone have the data laying around?

 

[lightman]

Re: .308 case volume

I've never seen it in ml,most reloaders weigh the cases capacity in grains of water.I use alcohol,as the results are more consistant.Something about the surface tension of water can be different. Lightman

 

[plant.one]

Re: .308 case volume

any solid basis for comparison is great in my eyes - weather it be volume or weigh based.

do you have any data on your alcohol tests with various brass then?

 

[BLDTYLRY]

Re: .308 case volume

Just answered this yesterday Click here

 

[plant.one]

Re: .308 case volume

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BLDTYLRY</div><div class="ubbcode-body">Here are the measurements I got. All brass was trimmed to 2.005" and were primed with CCI #200 Large Rifle Primers then filled with Varget to the brim.

Lapua Brass
Brass weight: 177.5gr
Max Powder Volume: 52.9gr

Winchester Brass
Brass weight: 159.6gr
Max Powder Volume: 54.4gr

Hornady Match Brass
Brass weight: 172.5gr
Max Powder Volume: 52.8gr

LC LR 07 Brass
Brass weight: 181.4gr
Max Powder Volume: 52.0gr

LC 09 Brass
Brass weight: 178.5gr
Max Powder Volume: 52.0gr </div></div>

using powder to measure case capacity - especially extruded powder - seems to be a less than optimal way to accurately measure volume, hence why i was looking for a liquid measurement. I have a couple of questions regarding your measurement techniques i'd appreciate a followup on if you dont mind sharing.

1) Did you do more than one measurement per case and then average them?

2) Did you take measurements on more than one case of each type? or just one random sample case per?

3) Did you 'settle' the powder by tapping the brass to make sure the voids were as full as possible or just dump powder in and go from there?

4) what scale did you use to measure the powder weight?

5) did you FL resize the brass before doing the testing? or were these fire formed cases that had only been neck sized, or no sizing at all?

 

[BLDTYLRY]

Re: .308 case volume

<span style="font-weight: bold">I chose to fill with Varget Powder as this was what I was really going to use. Did I scrape the top of each case mouth to ensure no grains were sticking up...no, but I used my calibrated right eye to measure fullness and the left eye to check.
</span>
1) Did you do more than one measurement per case and then average them? <span style="font-weight: bold">Measured 3 times for each case and all yielded the same value so Averaging was not an necessary.</span>

2) Did you take measurements on more than one case of each type? or just one random sample case per? <span style="font-weight: bold">Picked up the shiniest one from each manufacturer</span>

3) Did you 'settle' the powder by tapping the brass to make sure the voids were as full as possible or just dump powder in and go from there? <span style="font-weight: bold">Tapped side of case while filling</span>

4) what scale did you use to measure the powder weight? <span style="font-weight: bold">RCBS 1500 Chargemaster, calibrated with check weights first</span>

5) did you FL resize the brass before doing the testing? or were these fire formed cases that had only been neck sized, or no sizing at all? <span style="font-weight: bold">Brass was fully sized, trimmed and ready to go</span>

 

[Deadshot2]

Re: .308 case volume

I can't see personally how measuring by using powder would be all that consistent unless you have a way of vibrating the case until the powder's fully settled. Stick powders, and Varget is a classic example, tend to vary widely in how they settle when poured in. A long drop tube would help, so would a vibrator.

IMHO, water is still the best, if for no other reason than it's pretty much a standard for use in Internal Ballistic Programs.

I don't pay much attention to case capacity until I've fired it at least once. In my rifle the difference between F/L sized capacity and Fire Formed/neck sized is 1.5-2 gr of H20 using Winchester brass.

As for method. I use a sampling method, usually from a batch of 100 or so cases. I measure at least 10 cases and up to whatever I have the patience for. Those at the extremes of capacity spread are tossed into a bin that I load "foulers" with. Also my "teach the grandkids how to shoot" loads.

My "winnies" average 55 gr h20 in fire formed/neck sized form from my 5-R Milspec.

 

[BLDTYLRY]

Re: .308 case volume

Post your measurements and we'll compare max liquid vs powder case capacity

 

[lightman]

Re: .308 case volume

I looked,but I must have discarded the notes that I made.It probably would not help you much,as cases change from lot to lot.The cases that I played with two or three years ago will be different from any that you have.If I come across my notes,I'll post them.If I remember correctly;Lapua,Remington and Lake City weighed the most and had less volume.Winchester,Federal and Norma weighed the least and had more volume.Lake City,Norma and Lapua were the most consistent,both in dimension and volume.I think I used a random 10 from lots of 100. Lightman

 

[YAOG]

Re: .308 case volume

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: plant.one</div><div class="ubbcode-body">with all the recent discussion on .308 brass, and whats the 'best' brass, etc... i was wondering if anyone has the case volume (in ml) differences on the various common 308 brass on the market

FGGM
LC
Lapua
Winchester
Hornady Match
Remington

etc...

Does anyone have the data laying around? </div></div>


QuickLOAD users use grains of water. Per the QuickLOAD manual you scale empty fired cases complete with used primer. Fill the case with water and weight the case again to get H2O grains for use in QuickLOAD case volume calculations. I did this with 10 fired cases of some 40 year old commercial R&P brass and 10 cases of BHM brass. If was interesting to see the differences.

Both types of cases had previously been prepped uniformed primer pockets, uniform and deburr flash holes using the common Sinclair tools. The cases were full length sized using Redding Type S Match bushing neck dies then trimmed to 2.005" and loaded with the house 168gr A-Max load and fired.

I added a drop of dish soap to a small bowl of tap water and followed the QuickLOAD instructions to find H2O grain case capacity. Here are the 10 case average results:

R&P yielded 57.04 water grains
BHM yielded 54.4 water grains

HTH!

 

[timelinex]

Re: .308 case volume

I don't want to derail your post, but if anyone has any ml/grain capacity data on 338 lapue, please let me know!