So-

Did the chamber cast tonight, also measured some other features of what I have here.

To start, the rifling rate on this gun is about 1 in 40 inches. That was measured having pushed a tight patched jag through the bore on a dewey rod with timing marks drawn in pen on a piece of tape at each hundred and eighty degrees. A half revolution took about nineteen and seven eighths inches, measured once the patched jag was started and -just- got the rod turning.

The balls that came with the gun weigh in at 28.3 grams, they measure .666" in diameter.

There were two RWS gastight paper cartriges that came with the gun, they'd been cut to just about 1.695"
A cartrige with one of the sixteen bore balls set into the hull by having the ball sitting on the rifling then pushing the hull into the chamber gets the overall cartrige length from the head of the cartrige to the tip of the ball to 2.038"

The sixteen bore ball mold I got throws a cerrosafe casting of a ball at .666" in diameter.

The bore diameter of the rifle barrels is .650"
The groove diameter of these barrels is .666"

The chamber allows for a cartrige case length of 1.650"
Rim diameter is .785"
Rim thickness alowance is .053"
From the rim to the origin of rifling it's 1.666"
Diameter at the base is .756"
Diameter right at the throat of the chamber is .740"

I have yet to throw charges of black powder from the powder measure at each setting and weigh them, but I'll share that info once I do. I can't be sure the measure is the one made for this gun, but we'll just see...

Thinking about cartrige case designs tonight with an associate, we noted this thing definitely seems as if it's set up for paper hulls, the twist rate seems appropriate for one ounce balls.
I'll likely make my cases out of stainless and brass, with the heads of the cases done in stainless with inserts to hold pistol primers and the case walls made of brass, the walls silver brazed to machined stainless heads, the primer inserts done in stainless or brass (just typing this gives me the thought that brass will likely be the material for the inserts) and doing pins from a hard brazing (bronze alloy) rod. This'll make them easy to get the primers in and out, the pins will be cheap and easy to make, and the whole system should be relatively easy to load and clean.

Stuff to consider from here...

Bullet jump?
I wonder if this should be set up to slightly engrave the balls. The case walls will have miles of meat to work with and shouldn't stretch at all. They can be set up to cradle the balls -juuust right- to get the bullet jump to whatever would be optimal.
Powder charge?
The barrels and action on this gun look nearly showroom fresh. The rifle bores are absolutely goregeous. Load the thing till it hits at point of aim?
Hmm...
The powder measure that came in the case with this gun's been 'adjusted' with a cut plug of cork in the base of the cup. I found it in it's shortest adjustment. One of the cartrige hulls has what seems to be a pencil line on the outside, holding the powder measure next to that hull gets the base of that cork and the base of the cartrige to relatively the same spot when the top of the measure is at the pencil line.
Also of note about those two RWS Gastight hulls is that there's a liner of very thin sheet metal (very thick foil...) inside the hulls, it sets deep into the base of the hull and stops at about that pencil line.
For whatever it's worth, an Eley Gastight hull that I have that appears as it's never been fired or even loaded with powder or shot has a similar foil liner that is about as long as what I see in these specially cut RWS hulls.
I'd get about .330" or something like eight millimeters (or just better than 5/16") for wadding between the top of the powder charge and the ball when loaded out to where the ball just touches the rifling.

The evening's getting old, time to put the tools away till the sun comes up again.
Looking forward to what y'all you have to say about this.


thanks for your time

--John