Does anyone have first hand experience with this product?

Ballistic Bullet Testtube (http://www.thebullettesttube.com/index.html)

Have not used it but thanks for the link. It looks interesting. Was researching balistic geletin which seems like a PITA to create. At least this can be resused.

I've wondered about that, too, but don't know anyone who's tried it yet.

I have used stacks of wet newsprint that I get for nothing, are completely "adjustable", work in a wide range of temperatures, and which are very tolerant to shot placement. I think relative performance can be quite reliably observed, and that the wet paper is at least as relevant a measure as their special goop.

Seems like a very expensive way to get information that is no more meaningful than many other cheaper methods.

The difference between the goo and newsprint is that the cavity can actually be measured by volume, with liquid, and then captured as a cross sectional view for comparison. Most places I've found the item, sell them at about half what the manufacturers web site suggests. I do notice that some of the larger retailers are no longer stocking the items. I haven't found any reviews online against the items but not sure why the retailers are not stocking it.

How do you compress the newsprint so that it can be reliably measured?