quickload and water capacity variance

[SPAK]

Hey guys,

Been playing around with quickload and have question regarding water capacity. I've measuring my fired .30-06 lapua cases. 1x fired measured 69.1gr h20, 2x fired I got 69.5gr h20 and then 4th firing measured case capacity measured 69.7gr h20.

Which measurement is what needs to be used when calculating your OBT.

Brass has not been trimmed yet and the variance in length is within .005"

Any thoughts on whether or not I should use 1x fired or 2x fired cases for measuring capacity?

 

[ChrisGarrett]

Re: quickload and water capacity variance

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Frogman77</div><div class="ubbcode-body">Hey guys,

Been playing around with quickload and have question regarding water capacity. I've measuring my fired .30-06 lapua cases. 1x fired measured 69.1gr h20, 2x fired I got 69.5gr h20 and then 4th firing measured case capacity measured 69.7gr h20.

Which measurement is what needs to be used when calculating your OBT.

Brass has not been trimmed yet and the variance in length is within .005"

Any thoughts on whether or not I should use 1x fired or 2x fired cases for measuring capacity? </div></div>

Measuring water isn't an exact science. I'd just split the difference.

After 4 cycles, your brass is work hardening and not springing back as much, would be my guess for the discrepancy, so you get a larger vessel.

Chris

 

[jetsurgeon]

Re: quickload and water capacity variance

Frog,

I'll take a stab at it.....

Have the once, twice, and forth fired cases all been fired with the same bullet, powder, and powder charge?

Reason I ask is: I've noticed when I fire form cases from virgin (fired once) when I measure the h2O capacity, the capacity's are usually different (meaning higher) with cases shot with larger powder charges, then cases shot with lower charges.

In other other words, for example take 10 cases. Load 5 cases at say 25 grains, then load the remaining 5 cases 25.8 grains. When I've measured the higher charged cases, the h2O capacity is always larger. The cases are all very close within their respective 5 case lot, (either the lower or higher lots).

Myself: I take new brass, pick my starting load, shoot the cases, then measure the water capacity. Then I use that number in Quickload no matter what my later charge becomes. Also I anneal the cases every second firing.

I know this was long winded, but I hope it gives you somewhat of a direction.

All the best,
J

 

[jetsurgeon]

Re: quickload and water capacity variance

Yea plus what Chris said above.

 

[SPAK]

Re: quickload and water capacity variance

Thanks guys, yes cases we're fired with same charge and powder...good thought on the brass springback, I hadn't thought of that.

I figured the cases still needed a few firings to fully form to the chamber and perhaps that's where the discrepancy lies... It wasn't until the 3rd firing that I felt any slight resistance to the bolt closing on a fired case.

Thanks for the input!

 

[jetsurgeon]

Re: quickload and water capacity variance

Frog,

No problem, hope the info helped and you get it figured out.

J