Slitherine

I've been studying the various armor piercing ammunition produced by Germany during the war but have been unable to find concrete dates as to when they were introduced. I was considering creating specialized elite units that would have higher hard damage values to reflect this but without clear dates as to when the ammunition was introduced I have to make assumptions with the information I have.

I was hoping someone may have some better information about the following:

3,7 cm Pzgr. 40
5 cm Pzgr. 40
5 cm Pzgr. 40/1
5 cm Stiel-Gr. 42 (did this exist?)
7,5 cm Igr. 38 Hl/A
7,5 cm Igr. 38 Hl/B
7,5 cm Gr. 38 Hl (June 40?)
7,5 cm Gr. 38 Hl/A (Late 41?)
7,5 cm Gr. 38 Hl/B (By March 43?)
7,5 cm Gr. 38 Hl/C (Spring 44?)
7,5 cm Pzgr. 40
8,8 cm Pzgr. 40
8,8 cm Pzgr. 40/43
10 cm Pzgr. rot
10 cm Pzgr.
10 cm Gr. 39 Hl/A
10 cm Gr. 39 Hl/B
10 cm Gr. 39 Hl/C
15 cm Igr. 39 Hl
15 cm Igr. 39 Hl/A

What little information I have suggests the various Pzgr. 40 rounds were in production around mid 1942.

Anyone have any information?

It might be worth trying a more specialised site like Feldgrau or search for Ron Klages Panzer.
It's quite likely you'll find a few discussions on ammunition types and introduction dates.

That suggestion was helpful, I have more of an idea as to when these ammunitions were produced. For those who are interested this is what I have:

3,7 cm Pzgr. 40 (late 1940)
5 cm Pzgr. 40 (mid 1941)
5 cm Pzgr. 40/1
5 cm Stiel-Gr. 42 (mid 43?)
7,5 cm Igr. 38 Hl/A (June 41)
7,5 cm Igr. 38 Hl/B (September 42)
7,5 cm Gr. 38 Hl (June 40)
7,5 cm Gr. 38 Hl/A (June 41)
7,5 cm Gr. 38 Hl/B (September 42)
7,5 cm Gr. 38 Hl/C (May 44)
7,5 cm Pzgr. 40 (1942)
8,8 cm Pzgr. 40 (mid 42)
8,8 cm Pzgr. 40/43
10 cm Pzgr. rot
10 cm Pzgr.
10 cm Gr. 39 Hl/A (june 40)
10 cm Gr. 39 Hl/B (1941)
10 cm Gr. 39 Hl/C (1942)
15 cm Igr. 39 Hl (1941)
15 cm Igr. 39 Hl/A (1942)