Any ideas on measuring case volume?
- Thread starter cdn shooter
- Start date
Use an eye dropper.
Fill a glass with water and a splash of rubbing alcohol (takes the tension off the water)
Weigh the case with a spent primer in it (zero your scale if you have an electronic scale) then use the eye dropper to fill the case to the brim and re-weigh the full case.
The difference in the 2 weights will be the volume of H2O the case will hold.
Some use a ball or pistol powder or salt but I find this unreliable as you can fill a case with one of the mediums right to the rim, then if you tap the side of the case you will see the medium pack down into the case making room for more.....water will not pack down.
Have you ruled bullet runout and/or case neck uniformity from the equation?
Fill a glass with water and a splash of rubbing alcohol (takes the tension off the water)
Weigh the case with a spent primer in it (zero your scale if you have an electronic scale) then use the eye dropper to fill the case to the brim and re-weigh the full case.
The difference in the 2 weights will be the volume of H2O the case will hold.
Some use a ball or pistol powder or salt but I find this unreliable as you can fill a case with one of the mediums right to the rim, then if you tap the side of the case you will see the medium pack down into the case making room for more.....water will not pack down.
Have you ruled bullet runout and/or case neck uniformity from the equation?
I fill the case with water and then weigh the water with my powder scale
since water density ==> 1 litre=1 kilogram
1000 cc = 2.20462 lbs and 7000 grains = 1 lb
1000 cc = 15432 grains
the weight of water in grains divided by 15.432 = volume of case in cc
for example my R-P 308 winchester cases hold 54 grains of water
54/15.432 = 3.5 cc case capacity
I'm assuming this can be done with any medium as long as the medium
density and case filling is consistent
since water density ==> 1 litre=1 kilogram
1000 cc = 2.20462 lbs and 7000 grains = 1 lb
1000 cc = 15432 grains
the weight of water in grains divided by 15.432 = volume of case in cc
for example my R-P 308 winchester cases hold 54 grains of water
54/15.432 = 3.5 cc case capacity
I'm assuming this can be done with any medium as long as the medium
density and case filling is consistent
Thanks guys, I kind of fiqured this would have to be a liquid based test but there are some good ideas here. I tried this before and it is really tough with my redding beam scale. And to answer the case neck question. I am currently neck sizing with a lee collet and I havent spotted a good outside neck turner at any of the shops yet. Thats a whole different topic but does anyone know if you neck turn can you still use a lee collet? My accuracy rig is a 300wsm and that die leaves borderline neck tension as it is.
What do you mean by "borderline neck tension"?
What kind of press are you using? If you are using a press that will allow you to cam over (Lee Challenger will not do this) then set the Collet die so that the press over cams at the very end of the stroke. This will give you the same pressure on the collet everytime.
What kind of press are you using? If you are using a press that will allow you to cam over (Lee Challenger will not do this) then set the Collet die so that the press over cams at the very end of the stroke. This will give you the same pressure on the collet everytime.
Please tell us more about your rig. Rifle, barrel, caliber, scope, rest etc. How far out of the group are these fliers you speak of? And what distance are you shooting? Unless you have a custom chamber and need to neck turn, you are better off buying quality brass.
Im shooting a heavy barrel savage 300WSM 6x24 bushnell elite tactical at various distances, 100m being baseline groups. It shoots .4 to .5" with some groups approaching 1" at times. When I have a group like this there are two touching and "flyer" I'm not talking about pulled shots. The rifle has turned a few groups in the .2s as well.
Now to the neck tension issue. I started off with the die set the way lee calls for in their setup. After seating a bullet I could pull it out by hand. so I checked bullet, neck diameters and I had 1 thou tension. I then set the die a turn lower and resized. I then had 3 thou of tension but have to push into the die really hard.
Now to the neck tension issue. I started off with the die set the way lee calls for in their setup. After seating a bullet I could pull it out by hand. so I checked bullet, neck diameters and I had 1 thou tension. I then set the die a turn lower and resized. I then had 3 thou of tension but have to push into the die really hard.
It could be that with your barrel, load, bullet that's as good as it gets. What bullets are you using and have you tried other bullets? Is your action bedded and what type of rest are you using?
I agree with Cyan1de, you might want to try a bushing style neck die, but .002" to .003 isn't too much neck tension.
I agree with Cyan1de, you might want to try a bushing style neck die, but .002" to .003 isn't too much neck tension.
So I obtained volume on 40 cases last night and here is what I came up with.
Case dry weights vary from 14.8 to 15.5 grams with no one weight being common. Wet weight was from 20.2 to 20.8 grams with same inconsistency. the supprising thing however is the volume.
1 case at 5.2 g of water 16 at 5.3g 22 at 5.4g and 1 at 5.5g
I'm going to load the cases at 5.4g and then load the two oddballs to see if they in fact find a different point of impact from the rest.
I hope to get to the range today to try this out ( if it quits snowing).
And to answer your questions maynard the stock is tupperware unbedded. I have a 7mm build to do before the .30 gets a new stock but I forgot about this and your right that is quite probably the cause of the odd flyer. Bullets I have tried are 155gr-208gr. Berger, Nosler, Sierra, Hornady mostly match bullets. And I like to shoot from a set of hoppes sand filled shooting bags, I also shoot quite often prone off a harris bipod.
Case dry weights vary from 14.8 to 15.5 grams with no one weight being common. Wet weight was from 20.2 to 20.8 grams with same inconsistency. the supprising thing however is the volume.
1 case at 5.2 g of water 16 at 5.3g 22 at 5.4g and 1 at 5.5g
I'm going to load the cases at 5.4g and then load the two oddballs to see if they in fact find a different point of impact from the rest.
I hope to get to the range today to try this out ( if it quits snowing).
And to answer your questions maynard the stock is tupperware unbedded. I have a 7mm build to do before the .30 gets a new stock but I forgot about this and your right that is quite probably the cause of the odd flyer. Bullets I have tried are 155gr-208gr. Berger, Nosler, Sierra, Hornady mostly match bullets. And I like to shoot from a set of hoppes sand filled shooting bags, I also shoot quite often prone off a harris bipod.
