The Auto Prime with threaded shell holders was made by Lee Custom Engineering. For the whole story, read Richard Lee's article in Handloaders Digest, 17 th. ed. Lee Custom Engineering has been out of business since 1988, and Lee Precision does not make parts for those tools.
We do have a list of what letter shell holder corresponds to which calibers. I have provided it below for you.
A = 22 Hornet
AA = 25 Auto
B = 218 Bee, 25/20 WCF, 32/20
BB = 32 Short Colt, 32 Long Colt
C = 219 Zipper, 25/35, 30/30 Win, 32 Win Sp, 38/55
CC = 32 S&W, 32 S&W Long, 32 Colt NP
D = 225 Win, 220 Swift
DD = 32 Auto
E = 380 Auto, 221 Fireball, 222 Rem, 222 Rem Mag, 223 Rem
EE = 38/40, 44/40
F = 308 Win, 30-06, 22/250, 243 Win, 244 Rem/6mm Rem, 250/3000 Savage, 257 Roberts, 25/06, 270 Win, 284 Win, 280 Rem, 7x57 Mauser, 300 Savage, 8x57 Mauser, 358 Win
FF = 41 Long Colt
G = 6.5x55 Mauser
H = 35 Rem, 45 ACP
HH = 8mm Lebel
J = 257 Whby, 6.5 Rem Mag, 264 Win Mag, 270 Whby, 7mm Whby, 7mm Rem Mag, 7x61 Sharpe, 300 H&H Mag, 300 Win Mag, 300 Whby, 308 Norma Mag, 338 Win Mag, 340 Whby, 350 Rem Mag, 358 Norma Mag, 375 H&H Mag, 458 Win Mag
JJ = 303 Savage, 32/40
K = 30/40 Krag, 303 British, 35 Win, 44 Special, 44 Mag
L = 256 Win Mag, 22 Rem Jet, 38 S&W, 38 Short Colt, 38 Special, 357 Mag
LL = 401 Win Spl
M = 30 Mauser, 30 Luger, 38 ACP (38 Super), 9mm Luger
N = 41 Mag
NN = 224 Whby
O = 45 Auto Rim
OO = 378 Whby, 460 Whby
P = 45 Long Colt
PP = 38 Speer Plastic
R = 348 Win, 45/70 Govt
S = 7.62 Russian
T = 25 Rem, 30 Rem, 32 Rem, 351 Win Sp
U = 30 M1 Carbine
V = 6.5x 54 Mann. Sch.
W = 444 Marlin
X = 6.5 Jap, 7.65 Mauser, 7.7 Jap
Y = 9mm Luger
Z = 45 Colt
