Here is a set of bullets that came from sources associated with Colt, The first photo is a set of the individual projectiles that came from a collection of items included test targets and assorted material.
The second photo is a set of SSB bullets that came from the Ted Koch collection. Ted was close to Rob Roy of Colt and had quite a bit of experimental SSB material. Note that the weight of these rounds differ a great deal. on the front row, from left to right:
- 140gr-4 bullets
Second row all weigh between 103gr and 105gr with no significant differences except for some in the base of the projectiles
The last two bullets are from another collector who had close connections with Colt. These are two 115gr bullets fired down different squeeze bore barrels at Colt early in their 9mm SSB work. One is now 6.53mm and the other 7.64mm.
I was surprised to see the quadplex bullet. There were obviously a many variations attempted in developing these cartridges, and what we see is just the tip of the iceberg.