Rossi .454 Casull plinking load

[okthen]

I have a Rossi '92 in .454 Casull, and some Unique. I want to come up with a subsonic plinking load using Hornady Frontier Lead boolits that won't lead the bore. Should I use .452 or .454? Any advice will be most appreciated as I am new at this.
Thanks.

[missionary5155]

Greetings okthen and Welcome about !
I would use the .454 diameter and 7 grains of Unique. Hopefully your rifle´s throat area is not more than that.
That 7 grains of Unique is my favorite "quiet" load in all .41 + caliber pistol caliber lever guns. I use it in 41 mag, 44-40 and 45 Colt. Would be near the exact same in 454.

[RobS]

Go .454 as many Rossi 454 Casull bores have a .452 groove diameter, including mine. The chambers and throats are generous and will take .454-.455 sized SWC's with a .100 front drive band and .380 or a touch longer nose length so no issues with chambering of a round flap point.

You will play like hell trying to keep the brass case from swagging down on those soft bullets though. Having a case expander die to open up your brass case would greatly help in your reloading process. I would try a light load of Unique or similar in hopes that it puts enough pressures on the base of the bullet to allow it to obturate and fill the bore (assuming it is comming from the case undersized), but not put too much of an ars kicking that it skids the rifling.

The only way to know what is going on with bullet diameter once seated and crimped is to simply pull a bullet and measure the drive bands and in particular the very edge of the base band.

[Snyd]

Mine has a .452 bore and .454's chamber fine. Even the RCBS 45-405-fn which drops a 435gr .458 with a long nose. I sized them down to .454.

My plinkin loads are my 255 45 Colt 8 gr Unique or 275gr in 454 with 10. Maybe I'll have to try even lighter just for fun