I have another tray of workups for the 25 .
I'm exploring ;
Brass . After more digging I came up with 20 EW42 matched cases , a few WW and a few Super X. I loaded 5 ea with 12 gr Unique, plain base , and gas checked in the assorted cases .
Powder .
Throwing caution to the wind I started 1.5 gr below 120 jacketed data with the 125 gr cast and IMR 4831 with previous OAL . The idea being maybe this is just one of those barrel and bullet deals where it really wants to have a full snort and run wide open . Basically the load should pick up velocity where the Unique leaves off and about 8,000 psi less pressure with a longer push . The approximated velocity should be around 2400 to start into 2600 fps .

Herco data is like hens teeth . 300 gr data for 45 Colts is almost as bad .
Unique however runs from 6-7.0 for standard and up to 10.2 for Ruger/Contender up to about 25kpsi . The loads are primarily for that stupid 1-32 twist in the Rossi M92's . The SWC , 250-255 gr , in particular and to a lesser degree the 255-265 RNFPs don't return to subsonic well . I'm after a just barely sub sonic with enough heft to do what it needs to do . Anyway I started off with 7-8.5 gr of Herco that delivered round holes at 50 yd but probably only about 600 fps MV so I have this batch loaded 8.7 , 9.2 , and 9.6 gr mostly because thats where the measure hit . Typically what Herco data there is takes about another 1/2 gr over Unique for the same velocity in pistols ,it gains a little in longer barrels wo gaps . The Herco is slower and slightly bulkier . It should get me right into the window of 975-1025 fps .
If it works out I'll have to buy a 300 gr mould .