Does anyone know of something to add to water to make it less "sticky/clingy" to the brass cartridge when testing water capacities? I did some capacity testing some years back and remember adding something to the water but can't remember what it was. I'm thinking alcohol or dishsoap. Any thoughts or procedures for testing capacities using water would greatly be appreciated.

Get yourself Quickload or Loadfromadisk. These programs will calculate case capacity for you. Much better than fooling with water and its adhesion.

But I'm only interested in the capacity up to the bottom of the neck - what I call usable capacity. Besides, I tried using Loadfromadisk in the past to determine water capacity and it needed many dimensions of the case that I couldn't give unless I sectioned a case and took measurements. It just seems easier to insert a spent primer, weigh the case, then fill it with water to the base of the neck and reweigh.
I added dishsoap and went with that for my measurements. It worked well.

Stick,
Just a thought when I test for water capacity I zero my scale with the brass and then add the water. This way it right on the monney.

good luck.

big

I don't know if such places exist anymore, but there used to be photography stores that sold enlargers and film developing supplies for do-it-yourselfers. They had small bottles of some magic stuff that you'd put a drop or two in your developing tanks and it would break the surface tension and keep the water from beading up on your prints. Don't know what it is called but if you can find one of those old-fashioned stores the clerk should know what you're talking about. But, those stores have probably gone the way of everything else from my era.

ray

Spray the inside of a new case with mold or frying pan release. A light coat of W-D 40 followed with a swab will do. Get your self a small eye droper to extract excess water to the neck shoulder line. Th water will come out relatively easy. Weighing the case and than the case with the water as previously suggested is also a neat way. roger

I just use a very fine ball powder & a long drop tube.

Like Fred said H380, works way better than water

You should be able to use a normal detergent (washing up liquid)it will stop the surface tension of the water tension. That is what makes it stick and bead.
You will only need a tiny amount.

quote:

Originally posted by Blueprinted:
Like Fred said H380, works way better than water

Got a question
Using H 380 ball powder. Am I correct. This means H380 has a specific gravity of 1.0 (same as water). Are you using it to get a volume of powder to measure in cc and convert to weight. If so that is a good idea!
James

Thanks for all your input.

Johnny foreigner - The dishsoap worked well.

The reason behind my case capacity comparisons is that I'm trying to decide which case to neck down to 6.5mm. I'm looking at the 270 WSM or 7mm Rem SA Ultra Mag. Want something that betters the popular 6.5x284 by a couple 100 fps with the 140-142 gr. bullets. Most manuals only show the 6.5x284 achieving 2700-2800 fps with a 24-26" barrel using the 140 gr. Sierra MK. I want 3000 fps with the 142 gr. Sierra MK. I will shoot them moly'd which should help in the velocity department. I'm also looking at getting a 28" barrel. What do you guys think about this?

The 264 Win Mag gets 3000 fps with a 140 gr. out of a 24" barrel but I wanted to go with one of the short-fat cases that are more efficient and possibly more accurate than a run of the mill 264 Win Mag.

Thanks.

Because the 264 Win Mag will get more velocity than I want with moly'ed bullets & 28" barrel and the fact it has a reputation for being hard on barrels, I'm looking for something with 10 gr. or so less case capacity. I measured a 7mm Rem Mag case up to the bottom of the neck (same body as 264) and found it had a water capacity of 78.8 gr. So, something in the high 60's to low 70's should fit my requirements. The 7mm Rem SA Ultra Mag (Remington case) has a capacity of 68.6 gr while the 270 WSM (Norma case) has a bit more capacity at 72 gr. Since the two are so close, my decision as to which one to use is more difficult. I thought the Norma case would be more uniform than the Remington but upon measuring the neck thickness of both cases at 14 points around the circumference of the neck, the Remington was more uniform. Of course, this was with just one case and may not hold if I measured all of the cases I have from both manufacture's. Norma and Winchester make 270 WSM brass while only Remington makes the 7mm SA Ultra MAg. If I went with the Rem SA Ultra, I would purchase 1000 cases to ensure I have a sufficient quantity in case Remington decides to stop making them at some point down the road. Midway has the best price I've found for 1000 pieces for $299.99. Most other places want mid to low $300's.

Anyone have a suggestion as to which one I should go with and for what reason(s)?

Thanks.

quote:

Originally posted by jeh7mmmag:
Got a question
Using H 380 ball powder. Am I correct. This means H380 has a specific gravity of 1.0 (same as water). Are you using it to get a volume of powder to measure in cc and convert to weight. If so that is a good idea!
James

For me the purpose of measuring case cap. is to determine if brand X has a diff. cap. than brand Z. Any uniform measurement will give you this. Ball powder poured in w/ a drop tube gives you a specific weight/vol. measurement that is repeatable & accurate. It has nothing to do with the specific gravity of water. So what is exactly the purpose of using water as a spec. default? Do you use tap water or bottled, mineral or sparkling?

Bigstick, I have a 27" bbl. .260ai & can easily get 2800fps w/ 142grSMK. I would think the 6.5x284 would give you at least 2900fps+ w/ the same bbl. length. The 6.5x.284 has at least 8-10gr more cap. & in a std. action, you can load the long SMK out to give a bit more.

fredj338 - I am using water instead of powder because my garage is under construction and I don't have access to my bench & equipment. I'm in the house using water but jeh7mmmag is right, I could use powder such as H-380. I have used WC-860 (surplus 50BMG ball powder) in the past to compare case capacities of various cases as well as different brands within the same caliber. Why else water? Because its universal in that Barnes for instance reports case capacities in grains of water instead of choosing some powder and reporting that as the capacity. Its just a good universal substance to use that everyone can get there hands on.

Why not just go with a 6.5 Rem Mag? 350 Rem mag brass is available to neck down, pressure tested load data is widely available, the cartridge is a short action round, and 3000 fps is easily reached with a 140 bullet in the data I`ve seen. The 6.5 Rem mag was designed to equal 270 performance in a short action. It has similar capasity to a 270 win case.
The 284 Win was developed to do the same. It too has a capasity very close to the `06/280 Rem case. Benchresters report the 6.5x284 gives 2950-3000 fps with 28-30" barrels with no trouble. The 6.5x55 IMP does similar I`ve heard. IMO you won`t get much more then this without a case in the 264 win mag capasity range.

I was trying to avoid a belted case. Have had problems with belted cases in target guns. Your right though, I had seen that the 6.5mm Rem Mag could give me the velocities I was after but turned against it early on due to its belt. That's why I was ttrying to find a non-belted case with similar capacity in the hopes of equaling the 6.5 Rem's velocities. But I have no way of measuring its case capaicty for comparison purpose or have a source with this information. Therefore, I was using the 264 Win Mag capacity reduced by 10 gr. as a guide.

Stick: according to a reference I found, here are some relative capacities:

270....68
6.5RM...68
284...66
30-06....69
264...82

Have you considered a 6.5/06AI, that should get to pretty close to your goal of 10 grains under the 264, and a bit more than the 6.5/284. Plus no belt and plenty of cheap brass...

OTOH, if your goal is 3000fps with 140's, you can do that with very milds loads (read: long barrel life) in a 264WM...