Adjusting QuickLoad for VihtaVuori powders

[cwsanfor]

As described in another post, I had some rounds turn out much slower than QuickLoad predicted, and am curious if you have had the same issue, particularly with VihtaVuori powders.

I was loading 125 gr HAP over VV N330, and got deviations of up to 170 fps slower than predicted chronographing the rounds on a Shooting Chrony. Got a bullet stuck in a barrel as a result. To match up the predicted versus actual velocities I adjusted the Max Case Capacity from 13.3 to 13.8 (per my physical measurement), and had to adjust the Burning Rate Factor (Ba) from 3.1 to 2.6, putting it down in the N310 range. That seems like a lot, but my predictions with N330, N340, 3N37 now jive pretty well at all loadings. I have not had this problem with Power Pistol or TiteGroup, so the issue so far seem specific to VV powder. Anyone else seen this?

 

[rcmodel]

At best, Quickload is only a guesstimate.
There are a lot of things it can't or doesn't take into account.

And you know what they say about computer programs?
Garbage in, Garbage out.

Without telling the program the actual pressure & velocity you get out of your barrel, trying to tell you what velocity you will get is garbage.

rc

 

[RidgwayCO]

Agreed, QuickLOAD is not the divinely-inspired Holy Gospel, but merely a program written by mortal men and subject to flaws. However, it's the only thing this side of a pressure measurement lab that most of us can afford. It's saved me innumerable hours in eliminating inefficient powders when developing new loads.

I've found that the single most important variable the average user should adjust is actual average case capacity. Measure the water capacity (in grains) of several fired cases and average the results. This step alone has made my actual results much closer to the computed results.

And I haven't seen the VV powders varying markedly from QuickLOAD's predictions. The powder that seems to vary the most, for me at least, is Accurate #2. Luckily, there seems to be enough pressure-tested data for Accurate #2 that I can still use it in a variety of cartridges with confidence.

YMMV.

 

[MEHavey]

I start QL for a new Powder/Lot# with a half-dozen mid range loads.

Using actual case capacities, then adjusting burn rate (Ba) to match measured velocity at the shooting temperature, I find QL to be very reliable for other bullets/velocities/OALs/powder weights/reasonable temp changes, etc.

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