This might help out. According to the CS invoices, Samson & Pae was the only Richmond foundry making field-caliber ammunition for the imported Blakely guns. We have their month by month records for late 1861 and early 1862 when these were produced. "Steel Rifles" or "Steel guns" was their shorthand for the Blakely and other imported steel cannon. Confederates made cast iron or bronze guns. Although I don't emphasis it in the captions, I now think its possible that some of these 2.5 inch projectiles were imported with the two guns in 1861. I'm fairly certain that the two you own, Mike, are CS-made. Fired examples have been dug from Cedar Mountain to Antietam. Afterwards, into the Artillery Reserve until sent to the Western Theater in 1863. Samson & Pae were widely respected for their skilled workforce and as innovators. It would be like them to constantly try to improve their projectiles with grooves added to the base.