SG,
The cases for 44 Rem are 44 Colt by Starline. .451-.452 outside dia Nom. the bullet is what makes it 44 Rem. The inside dia.of the cases are .429 (same Dia as heel Dia. of the .248 grn bullet so you bell the case just a might, seat the bullet and crimp or not. the bullet is tightenough inside the case so as not to need crimping. The Cartridges do not come apart in the chambers during firing. I have fired them both ways..
This the original loading for 44 Remington conversions and Colt Conversions.
This was made and sold by Remington(UMC?) Remington conversions and Colt conversions until 1895. This , I believe is the same as the original 44 CF, so they interchange between Colt and Rem. Since 1940 or so the 44 Colts made after this(None made between 1900-1940 as I recall) the new 44 Colt is .439 grooves. As I understand it.The 1872 Colt Open top clones shoot this bullet, but the original Colt Open Tops shoot the 44 Rem. Because they were .451 Nom Grooves. As I understasnd it, all 44 CF conversions of original 44 C&B revolvers had .451 grooves.
You are right. the 44 Colt bullet shouldn't shoot in the Rem.451-452 bbl, but for some reason the ones I have here did shoot pretty well. now whether it was tip up (expansion) of the bullet or the fouling in bbl...I haven't a clue.
Clear as mud , now. Right?