Range Report Case volumes for different .308 cases

[ReaperDriver]

Hey guys, I'm playing around with QL and measuring my various cases doing the water volume thing. What are you guys getting for case capacities so I can see if I'm close and doing the process correctly?

For comparison. my measured max case capacity (overflow):

Lapua = 57.11 grs of water
Winchester = 58.47

Is this in the ballpark for what you guys that have done the water measurement thing have come up with?

 

[Grump]

Re: Case volumes for different .308 cases

Did you even try your Search-fu?

 

[ReaperDriver]

Re: Case volumes for different .308 cases

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Grump</div><div class="ubbcode-body">Did you even try your Search-fu? </div></div>

Yes, both mine and SH's search fu is weak.

I think where I am confused is when QL states to measure the "overflow capacity", yet that's not defined anywhere. I took it to mean that you add water until it overflows, but because of the surface tension of the water, I end up with a pretty pronounced "bubble" above the case mouth (that what the #'s above are based on). I also tried to measure where the water is just level with the case mouth and that got me closer to the correct velocities in QL.

I did read on another forum where one guy suggests seating a bullet at the correct depth in a case without a primer. Then you fill the case with water from the flashole. I may try that technique too. The problem is QL already subtracts the bullet volume when you tell it the seating depth.

 

[Swan]

Re: Case volumes for different .308 cases

maybe this?:

http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1448406

 

[MontanaMarine]

Re: Case volumes for different .308 cases

I get around 56.0gr in milsurp, and 58.0gr in Win.

 

[ReaperDriver]

Re: Case volumes for different .308 cases

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Swan</div><div class="ubbcode-body">maybe this?:

http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1448406 </div></div>

YES! My search fu is weak and yours is obviously strong, swanny

Thanks, that was exactly what I was looking for. I was trying to figure out how much of a convex meniscus they meant by overflow. Because with a syribge, I could get a ridiculously high meniscus due to surface tension (I was also a bio/chem major in college). But that big bubble didn't make sense. I think I have it now and some cases I re-measured last night with a very slightly convex meniscus seems to get my QL numbers much closer to my chrono data.

 

[Grump]

Re: Case volumes for different .308 cases

Reaperdude:

Try this one, too: http://www.snipershide.com/forum/ubbthre...rue#Post2115884

It's only a week old.

SH search started working for me after I finally read the instructions and learned that it's NOT a Google-style "and" in between every term, but "OR". To make it "and", add + with no space to the front of every required word.

Hope this helps.

Grump the impatient.

 

[Grump]

Re: Case volumes for different .308 cases

This one started two days earlier but apparently drew only yawns. http://www.snipershide.com/forum/ubbthre...rue#Post2106270

Same data was reported in the other thread.

Since then, I re-checked a few more FA63s and they came out to...get this...exactly 56.0. I even checked the spreadsheet's math, and also made sure the source data was NOT the same as for the LC86. It's correct for that new sample.