H2O / Powder Ratio

[Rockdoc173]

I'm preparing a 7mm-6.5 PRC project and I'm working on developing some theoretical numbers. Using a Mac means I don't have the luxury of Quickload, which kinda sucks. My reamer was ordered such that I'll be running the 180gr Hybrid in a SA, so sunk down in the case a little lower than I would've liked but remain satisfied with nonetheless. I'm trying to figure expected velocity for different powders, so I got to thinking about how I was going to do that. H20 is the obvious medium used to measure case volume, so is there a list of water-x powder ratios somewhere? For example, the first powder I want to use is RL-26, so this ratio table might say that a x measured volume of water (maybe 1in3 or 1cm3) is equal to x grains of RL-26. Obviously this is volumetric and therefore dependent on several factors, but I'm just looking for a generalized estimate. How cool would it be to have an app where in a guy could select his case dimensions, bullet, OAL, and powder and get a approximations on case capacity/volume, velocity, etc. Is that Quickload? Like I said, I've never used it. Anyway, thoughts on the ratio table would be appreciated. Or, if a better way exist please feel free to share

 

[Steel head]

As your probably aware density varies among powders.
If you seat a bullet where it’s approximately going to be and then check water capacity you’ll get a workable usable volume then this program can help you out.

P-Max internal ballistics

www.p-max.uk

With accurate inputs it’s predicted speeds and approximate pressures have been surprisingly accurate with multiple cartridges from 223 to 338 and it’s solids predictions are accurate.

 

[Bmghunter]

Quick load does what you ask. It has a case volume fill ratio after bullet seating.
You can run a VM windows to run quick load. Maybe even use Linux and wine. There's also Gordon's reloading tool that's free (but current development paused) that you can try out in this configuration before buying quickload (if needed).

 

[Rockdoc173]

Quick load does what you ask. It has a case volume fill ratio after bullet seating.
You can run a VM windows to run quick load. Maybe even use Linux and wine. There's also Gordon's reloading tool that's free (but current development paused) that you can try out in this configuration before buying quickload (if needed).

I'm looking at using Bootcamp for this purpose. It'll take me a bit to get up on the software. Does Quickload use pre-loaded case dimensions, like 6.5 PRC? Or, can you input dimensions to account for the geometry change when going to a 7mm?

 

[Tchitcherine]

What is the best method for measuring case volume fill ratio after bullet seating?

 

[Choid]

What is the best method for measuring case volume fill ratio after bullet seating?

Quickload, anybody here will do it for you if you ask.

 

[Rockdoc173]

What is the best method for measuring case volume fill ratio after bullet seating?

I figured out the case volume assuming a given COAL today simply by the cylindrical volume up to the base of the boat tail. However, I ran out of time to work on breaking down the smaller "pieces" around it. I'm not sure how that translates into fill ratio though since I have no point of reference