I think I've got an odd one:
I reload 7.62x39. Since the only gun I have in that caliber is an AR-15, (they're all ARs, and not a one in glorified-22) I've bought the "modified case" to see how long the chamber is -- and the bullet won't touch until COAL of 2.5"
On small problem: if I want more than two rounds in my magazine, I'm limited to 2.46" which is the internal length of the D&H/ASC mags I have.
Why reload the cheapest surplus round available? Because I want a heavier bullet. Aiming mostly for the 147gr 7.62 NATO pulls that seem to come from decomissioned thai ammo, but the AMAX 155gr is shooting fine too.
Quickload says H335 would be the best, but I've used 1680, N110 from vv, and Aliant Reloader-7. I also have BL-C(2) for my grendel which is pretty similar although that chamber shipped at 2.19 and I had to get a throat reamer then didn't check often enough and now I have a 2.7 chamber just like my buddy's 7.62x39.
My dream is to build a wildcat starting with 6.8 brass, a 50d neck and 7mm, 200gr Berger or Lapua projectiles.
Again, Quickload says that the SF033 used in 5.45 would be the best -- you know, if anybody sold combloc powder separate from the projectiles. Winchester 296 might have come in second, or I might have been thinking of the raptor loads.