Loading low weight TSS

[ErlingElev]

Sorry for my bad Italian.
Based on sectional density SD, the size of a TSS shot is equivalent 3mm PB shot:

TSS diameter = PB density x PB diameter / TSS density

11,34 x 3 / 18 = 1,89mm

For capercaillie and woodgrouse I normally use a heavy load of 38 grams, which is approx. 240 shots. 240 shots of 1,9 TSS is 15,5 grams. This might not have the same killing effect, and it might not have the same momentum, but I leave that for now. I will do testing on this in the next phase.

The wads will be 12 and 20 cal BP steel wads with mylar wrap between and buffer.

How do I find loading data for this light TSS charge? With the buffer and both the wads the load is 18-19 grams. At 18 grams TSS this is around 20 grams. Ammox.fi has a load on that for 12/76 with 2,4-2,5 grams N320 with a speed on 600m/s. I would like around 450m/s in a 12/70.

Culot on this forum is referring to what is called “controdose” for the low weight charges.
Any suggestions?

I have A1, Longshot and the Vihtavuori powders are available here.